Why Fast? Part Six – Choosing a Method

Assuming you’ve been keeping up with the series, you should be saying to yourself “Hey, maybe this fasting thing would be a cool thing to try out, and it might even make me healthier/live longer/lean out/lose weight/etc.,” which is a sufficiently extensive list of benefits, don’t you think? I could probably go on theorizing and speculating about all the reasons why you should consider intermittent fasting, but I’d rather move on to the implementation. Thinking about fasting, reading about fasting, and reciting the benefits of fasting are all pointless if you don’t know how to go about doing it.

First, let’s go over the different variations of fasting. I’ll give a quick rundown. Each involves not eating for a period of time, unsurprisingly.

A couple other rules that apply to all the given methods:

  1. Sleeping hours (provided you don’t sleep-eat) count as fasting hours.
  2. Eat well regardless. While some fasting plans tout their adherents’ ability to eat crappy food and still lose weight, I’m not interested in fasting solely as a weight loss method.

Okay, on to the variations.


Martin Berkhan’s incredibly popular fasting protocol is slightly more involved than others, but still pretty simple:

  1. A daily 16 hour fast (Martin sometimes recommends 14 for women, who just seem to do better on shorter fasts) during which you eat nothing. Coffee, tea, and other non-caloric fluids are fine.
  2. A daily 8 hour (or 10 for women) eating window.
  3. Three days of weight training, ideally performed at the tail end of the fasting period. To improve performance and muscle protein synthesis, you have the option of consuming 10 grams of branched chain amino acids 10 minutes before the workout.
  4. Always eat high protein.
  5. On training days, eat more carbs and less fat.
  6. On rest days, eat more fat, fewer carbs, and slightly reduce calories.
  7. Most people begin their fast after dinner (say, 9 PM), workout in the afternoon (at around 12 PM), and break their fast immediately post-workout (at around 1 PM), but you can use any schedule you prefer.
  8. Your post-workout meal should have about 50% of your day’s caloric allotment (a real feast).

Who should try it?

Because it’s geared toward people interested in losing fat and putting on muscle and strength, Leangains presupposes that you will also be lifting heavy things several times a week, usually in the fasted state. Therefore, Leangains is best-suited for people who will be training on a regular basis. In fact, it’s probably the most meticulously-designed IF program.

People with steady schedules will have more success than people with erratic schedules. A huge part of Leangains is the hormonal entrainment induced by regular feeding times. Once you get locked into your routine, your hunger hormones will adapt to the schedule, and the fasting should get easier, or even effortless.

Eat Stop Eat

Put together by Brad Pilon, Eat Stop Eat is really basic:

  1. Once or twice a week, don’t eat for 24 hours.
  2. Start your fast in the morning, at lunch, or at dinner. It doesn’t matter as long as you don’t eat for 24 hours.
  3. Break your fast with a “normal-sized meal.” Don’t try to make up for the lost calories by feasting.
  4. Exercise regularly.

Who should try it?

People interesting in fasting for the therapeutic benefits (cancer protection, autophagy, life extension, etc.) would probably get a lot out of this method, as opposed to people interested in the body composition benefits.

Going a full 24 hours without food is a much tougher slog than going for 16 hours. In my experience, going lower-carb and higher-fat makes longer fasts easier, so I’d have to say a low-carb Primal eater would do better than most.

The Warrior Diet

Ori Hofmekler’s plan is based on the feast-and-fast concept:

  1. Eat one meal a day, at night, and make it a big one. A real feast. You have three or four hours to eat until full. So it’s basically 20/4 hours.
  2. You can occasionally snack on low-calorie raw fruit and vegetables during the day, but try to limit protein as much as possible until the feast.
  3. Exercise during the day, in a fasted state.

Who should try it?

People who have trouble sticking to a stricter fast will do better on the Warrior Diet, as it allows light eating during the time leading up to the feast, but I wonder if you’d be squandering some of the benefits by eating.

Alternate Day Fasting

Researchers often use this method in lab studies:

  1. Eat normally one day (last meal at, say, 9 PM Monday).
  2. Don’t eat the next day.
  3. Resume eating the day after that (at, say, 9 AM Wednesday).
  4. It works out to a 36-ish hour fast, although there’s plenty of wiggle room. You could eat at 10 PM Monday and break the fast at 6 AM Wednesday for a “mere” 32 hour fast.

Who should try it?

People who have no trouble going to bed hungry. With Leangains, Eat Stop Eat, and the Warrior Diet methods, you can always manage to get to bed with a full belly; with ADF, you will be going to bed on an empty stomach several times a week. That can be tough.

That said, the therapeutic benefits to serious conditions will most likely really be pronounced with this way of fasting. The casual 20-something Primal eater who lifts heavy things and enjoys going out with friends? Probably not ideal. The older Primal eater interested in generating some autophagy and maybe staving off neurodegeneration? It might just work out. And while I’m not able to tell a cancer patient undergoing chemotherapy what to do, I’d guess that the longer fasts will be more beneficial in that regard, too.

But my personal favorite way of implementing fasting?

Eat WHEN – When Hunger Ensues Naturally

I’m not going to put any bullet points here, because none are required. Instead, I’ll give a few scenarios:

I wake up bright and early on a Saturday morning. It’s about 65 degrees, the sun’s out, Buddha’s walking around with the leash in his mouth, and Red Rock Canyon is kinda calling my name. I’ve got my coffee already and I’m actually not all that hungry from dinner. You know what? I’ll go on that hike, skip breakfast, and really work up an appetite for lunch. Or not. If I’m hungry afterwards, I’ll eat. It’s a fast, but not really.

I hit the gym, put in a light workout, then swing by the beach for some sand sprints. I’m toast by the end and have to stagger back to my car, but I’m not hungry. Even when I get home and smell the grilled salmon, I have no desire for it. I might eat later that night, but only if my appetite returns. I’m fasting post-workout only because it doesn’t occur to me to eat, not because I’m following a plan.

I’m away on business, stuck on a layover that’s turned into a delay that’s turned into an overnighter. The only food available is a Kudos candy bar – I mean, healthy granola bar (they seriously still make these?) from the mini fridge, a greasy pizza joint on the corner across the street from the hotel, a Chinese takeout place next to the pizza joint, and a slew of fast food restaurants some ways down the road. It’s late, I’m tired, I had a Big Ass Salad before I left for LAX… you know what? I’m just going to skip the “meal.” I’ll figure out something at the airport in the morning (20 hour fast) or once I land (24 hour fast). And I’ll be okay either way.

That’s eating When Hunger Ensues Naturally.

This is the most natural, most effortless way of “fasting,” at least for me, because it allows a person to eat intuitively. Although most people will eventually acclimate to more regimented fasting schedules, and many may even need and thrive with that structure, I prefer a more fractal, loose, random pattern of “missing” (in quotations because I don’t feel like I’m missing anything, and that’s the whole point!) meals. I have no data on whether it’s as effective or more effective than the more popular methods, but I do know that I’ll often fast for 16 hours and eat for eight, or skip an entire day of eating, or sometimes (but very, very rarely) even approach a full 30 hours, and it seems likely that this random pattern of eating characterized the eating “schedules” of our ancestors.

In short, we’re all doing the same thing, chasing the same goals. We’re all skipping meals, reducing calories, staying active, and all the while we’re doing this without feeling miserable and restricted. It just so happens that because we’re efficient Primal fat-burning beasts, switching over to burning our own body fat reserves for energy during a fast is a natural, seamless transition. We often don’t even notice it. There’s no effort involved.

That’s the key: lack of stress. If any or all of these fasting methods stress you out, make you irritable, kill your performance, make you feel restricted, or reduce your ability to enjoy life, and these feelings persist beyond the first five fasts you attempt (when some adaptation difficulties are totally expected), you shouldn’t employ them. You should shelve fasting for a while and come back to it later, or never. It’s not a “requirement” or anything. It’s just a tool you can wield if your situation warrants it. In fact, this is the perfect opportunity to conduct an informal experiment of one. Try Leangains for a week or two, then throw in a full 24 hour fast once or twice a week for a bit, then try the WHEN method. Compare and contrast. How did you feel? How did you perform at work, at home, and in the gym? Take some waist measurements perhaps, or analyze your favorite barometer of body composition to see how the different fasting methods worked – or didn’t work – for you.

Now, I’d like to hear from you. What’s your favorite fasting method? Do you have one, or you just kinda go with the flow? Be sure to review the previous installments below and if you have any questions about any of the stuff I’ve covered in this series, leave them in the comment section and I’ll try to get them answered for you next week. Thanks for reading!

Here’s the entire series for easy reference:

Why Fast? Part One – Weight Loss

Why Fast? Part Two – Cancer

Why Fast? Part Three – Longevity

Why Fast? Part Four – Brain Health

Why Fast? Part Five – Exercise

Why Fast? Part Six – Choosing a Method

Why Fast? Part Seven – Q&A

Dear Mark: Women and Intermittent Fasting

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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242 thoughts on “Why Fast? Part Six – Choosing a Method”

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  1. Going with the flow and applying WHEN has me satisfied so that I doubt I’ll try another method anytime soon. Thanks for the info! Great series and I love the discussions that ensue.

    1. Same here. In the morning, I don’t eat until I have a appetite. Sometimes that is when I get up. On those mornings, I immediately have something like bacon and eggs, and maybe a little fruit. Then I may have only a snack e.g. some nuts between then and dinner. Or I might have a light salad for lunch. Other days I am not hungry until 11 or even noon.

      1. Same here. I do 16 hours when I feel like it. Not regularly though. Longer ones are not for me. And definitely no high sugar 50% of calories during one sitting AKA Leangains. Tried it and it brought back my cravings and expanded my belly – sixpack or not, a big belly is not a pleasant sight 🙂

        1. Yay to 16 hour fasts. This is just how my body likes it most of the time.

          Nay to one-day massive carb-ups. While they do make my muscles look more impressive afterwards, the horrible bloating on the day of just isn’t worth it.

      2. What if you need energy for a job? How do we know you’re telling the truth?

    2. HI, I tried to post but not sure if it worked. Have been IF for about two weeks. 14-16 hour fast each day. Wondering if it is okay to do if trying to get pregnant. Worried it might reduce my changes of conceiving??

      1. hi. i am a midwifery student and from what my teachers have told me it is very good to do a fast a few weeks before conceiving, then the weeks prior to conception its best to eat as much nourishing things as possible. once pregnant i don’t believe even a 12 hour fast would be a good idea.

    3. Mark Sisson is just talking out of his brain-dead ass. Fasting makes people weaker, it makes it difficult to think clearly, it makes people vulnerable to infectious diseases, and people at work will subject you to well-deserved ridicule. Sisson and his brainless, luddite, anti-religious, racist followers need some good, hard skull crackings in reality.

      1. You do realize people fast for religious reasons all the time right? Easter just passed and I fasted for the week. I ate occasionally, but to be honest I still had energy and though I had cravings, they eventually went away. PS: You need a hug. Not sure why you carry so much hate, but its not serving you. Life’s too short to spend it so angry

      2. I’m upset because it didn’t work for me and I am still obese so I criticize everyone and everything. I’m a deadbeat.

        1. If it didn’t work and you were really doing it right, I grow more concerned for your hormones and health. This works on almost all my patients except those with thyroid issues or other more severe problems. You may need to get checked.

        2. No, you’re upset because you’ve screwed up your endogenous endorphin production via some type of mind-altering chemical abuse. The road back is long and even more depressing. Good luck.

    4. I have been complete fasting for 3 days now . I started at 120.5 kilos now 116 kilos neat. I have been drinking lots of water and have had a cup of coffe or tea each day no sugar or sweetner. I dont feel hungry any more ,i have lost the bloated feel i had. Today i have plenty of energy and i am in a fairly high state of ketosis ( checked urine by keto strips). I did get a bit of a headace after the first 24 hrs as my body (liver) switched to burning fat instead of sugar. I will keep up my fast until the weight loss tapers off to less than 1/2 a kilo per day then i will slowly start to eat small amounts of pure protein (steak, bacon,eggs) . I am hoping to lose around 10 kilos in 10 days then i can slowly add vegeis etc and start to exerecise more. I should be able to ride my push bike without flattening the tyres by then. I will let you know how i go. By the way I started the fast first off my own acoord. I just felt it was something i needed to do. I then decide to check the web to see if there was any reason i should not be fasting, thats when i found this article.


      1. Now on my 4th morning weighing in at 115.2 kg thats 5 kilos lighter in 4 days . Im feeling good not at all hungry, dont think i could run 5ks but im up to working around the yard and doing most of my usual routine. I have a doctors apointment this evening so i will have my blood sugar levels checked. I had full bloods taken the day before i started to fast including liver function etc. It will be interesting to see what changes if any occur when i finish fasting. I am seriously thinking of staying on the fast for around 30 days this will hopefully get my weight below 90 kg and put an end to my fatty liver.


  2. I have been doing essentially Eat Stop Eat (I call it starving Thursdays) for a couple of months now. I have to say that as long as my last meal before the fast and my first meal after the fast are mostly protein and fat, I hardly notice the circa 26 hour fast. And this form of fasting has really accelerated my excess body weight loss. (24 lbs in less than 3 months).

    1. Might want to try something different, I don’t think you can go through life never eating all you want.

  3. I just tried “Eat, Stop, Eat” yesterday and did okay. A few moments of hunger but mostly I felt really good and alive.

    I just started a powerlifting regimen, however, and I’m going to keep an eye on my strength gains. Has anyone had experience with actually gaining strength while doing this or another fasting program?

    1. It depends on your current level of strength. If you’re new to powerlifting, you can pretty much gain strength doing anything. Just the simple act of lifting a few heavy weights will make you stronger.

      If you’re an advanced lifter (i.e., someone who can squat/dead 400+ and bench 250+), you’ll probably find it hard to make strength gains when fasting.

      I don’t have any hard data on this, but I know several advanced lifters whose numbers plateaued or even dropped when implementing a fasting regimen. You pretty much have to eat lots of food to make strength gains when you get to that point.

      1. If you are at that point, is there really a reason to continue eating large quantities in order to gain strength?

        Isn’t the goal to be lean and healthy?

        1. Good point. How about the goal being: Lean, getting stronger, and being healthy?
          My fasts affect the workouts. The performance drops. Food is energy. Energy=good workout results. Fasts = subpar workouts for me. So, I eat a little prior to and after workouts, which keeps me going strong and shortens wod rcovery.

        2. “Isn’t the goal to be lean and healthy?”

          Really? What is “the” goal? Your goal is whatever the hell your goal is, not whatever you hope is the consensus goal.

        3. The goal for Brian seems to also include powerlifting, which means he wants to get really strong. Not everyone’s goals are exclusively about getting lean an healthy.

        4. I agree and disagree with David below. Energy does mean for good performance in your workout but a ‘poor performance workout’ doesn’t exclude results. I’ve found that my deads, squat and bench all went up doing fasted workouts. My workouts would suck in the morning but every couple of weeks I would do an evening benchmark workout and find my 1RM. Even though my fasted lifting was sub par in the moment it resulted in huge gains when fed.

    2. I have one meal a day four days a week (mostly because I enjoy eating my face off once a day), I’ve noticed both strength gains and strength losses during the years I’ve been doing this, and imo it’s not tied to how often you eat but to total caloric intake/outake.

      If you are running a caloric deficit then it doesn’t matter how frequently you eat, gaining strength is going to be very tough.

      Right now I’m trying to get leaner cause I’m running a lot, so naturally I’m losing strength … has nothing to do with how frequently I eat. If I was focusing on getting stronger I would try to consume an extra 500 calories with dinner.

      1. Thanks. I need to lose quite a bit of body fat. I’m trying to walk a fine line between gaining strength for fitness and losing fat for health and appearance. I don’t want to do too much of one at the expense of the other.

        Leangains may be a better option for me.

        1. The general consensus in the LG community is that LG is more suited to someone who has already gained strength on a program like Starting Strength or Strong Lifts and is now looking for body recomposition – i.e. dropping body fat levels to single figures.

          My own experience has been that a program like Starting Strength is really tough on LG so I have decided to just focus on strength and worry about fat later.

          Make the most of newb gains while you can. Don’t worry too much about body fat until you can deadlift 2x body weight, squat 1.5xBW and bench BW

          That said, you will still lose some body fat even without following LG if you’re lifting heavy and adding weight to the bar every workout as well as generally eating primal (with a few extra potatoes and milk)

          Let your body be the guide. If your lifts stall or you’re struggling to recover, add calories. If your lifts are fine but your pants are tighter around the waist drop some calories.

          Hope that helps.

        2. Leangains is for guys who want to look like Berkhan, like natural bodybuilders. If you just want to burn fat and get lean and stronger, follow Mark on this. His results are easily sustainable without much effort under any condition, while the results of a Leangains style training go away easily and quickly once you stop following the regime for a while for whatever reason.

        3. Brian, if you can share your current lifting PRs (squat, dead, bench), it will help. You might be able to fast and restrict calories while still making strength gains. It really depends on your current level of strength.

        4. I have found that it’s hard to “do it all” at once. I.e., pick one of the two goals – get strong, or get lean. That said, most of what Rippetoe posts will tell you that most folks over 20%, even if they are “eating for strength” can still lose body fat on the SS or an intermediate program – you’re going to burn off a lot of the calories you take in through lifting. It won’t get you down to single digit body fat, but you probably won’t stay above 25%, either.

          A lot of it, IMHO, comes back to WHAT you’re eating for strength. If you are sticking to a paleo/primal based, clean protein an veggies, intake while lifting lots of heavy things, then you’ll drop weight. If you’re on whole milk, GOMAD (which Rippetoe recommends for skinny kids trying to bulk up and gain strength) then, yeah, losing fat is going to be a bit harder.

          Brian, based on what you’ve wrote, I would suggest the Leangains. And, from what has been posted earlier – IF is kind of an “intermediate” step, to be taken after the paleo/primal way of eating is your new “norm.” I wouldn’t personally try IF with a person very new to primal/paleo.

    3. I feel that all my gains come from recovery from training hard and not the actual workout, per se. It took me a few weeks to get dialed in to train as hard as I was used to in an unfasted state but once I did the gains came.

      Recovery is really key to making gains. Replenish protein and other micro nutrients and get plenty of rest (sleep).

    4. I was following the fasted training protocol with 10 grams of BCAA pre-workout, Leangains style, because I was trying to make strength gains. My strength gains were steady with that, but they practically doubled after I ditched the BCAA pre-workout. Like 2% gains every week instead of 1%.

      Personally, I can get extra rep on everything, past the progression that I’ve planned, training completely fasted. A rep is fairly big considering I work with my 4-8 RM.

      Now, I train exclusively in the completely fasted state. I guess I’m that guy… It fit’s my schedule and I love it.

      In my experience, the strength gains fasted come easier compared to fed training. Everyone is a little different though.

      You’ll definitely see results.

    5. I’m doing 300+ deadlifts for reps and following the leangains scheme with a primal twist. It’s working great so far (4 months in).

    6. I also use a power lifting type program (and I guess that I’d qualify as one of those advanced lifters according to his classification) and I have been experimenting with ~16 hour fasts on my off days with no ill effects.. I’ve still been getting no new PR s and gaining muscle

    7. I realize I’m replying to an old post, but for the sake of others who may have the same question… I have had strength gains on heavy deadlifts, squats, and weighted dips while doing Warrior diet and also while doing leangains style IF. And im talking about week after week gains, not just occasional gains.

  4. Mark – Thanks for the whole series on IF it has been very informative. Personally, I follow Martin’s method. It’s just easier for me to stay in a routine plus once I got into it, my hunger did change. So even though I stick to it during the week, I find on the weekends I automatically stick to it without even thinking about it. Also, I much prefer to do my workouts in a fasted state. I’ve been sticking to this pretty well since the first of the the year and have managed to gain strength on my workouts and lose 14lbs of fat – I’m not overweight, just trying to get in better shape and this method seems to work even for a 43 year old female !!!

    1. Thanks for sharing this Tammy. I’ve been really interested in giving it a go with so much good information from Mark, but then I read the info about Women and fasting and it left me undecided.
      You’re posting has encouraged me to give it a go. Thanks.

  5. Mark,

    Great post, and perfect timing! I’ve been trying a few of these methods for the past few weeks, and still deciding which I like most, but I have a question on the LeanGains method. On the lifting / higher-carb days, would you follow the 250g – 300g carb guideline that you discussed in your carb refeed post? At 3 times per week, it seems like it might be overdoing it a little, no? Would you just slightly emphasize carbs over fats, but stick to 150g max as recommended in the the PB? What are your thoughts on this?

    Thanks so much Mark,


    1. I also was wondering about the amount of carbs to eat on training days if you are following the lean gains program.

      What’s your thoughts Mark?

    2. You don’t want to do a carb refeed with a lot of fat if fat loss is your goal. Go to my website and check out the article titled “Insulin Spikes” for the details on that.

      300 grams is usually good for a healthy man, and 200 for a healthy woman.

      I do a refeed once every 3 days, but I also only train once every 3 days.

      1. I don’t know man, 300g sounds awfully high for 3 days a week. I think I’m going to start out at ~200g carbs (mix of sweet potatoes, LOTS of cruciferous veggies, and only a little sugar from frozen cherries and blueberries) and see how that works out for me. I also plan on following Marks / Martin’s advice on keeping fat low – under 50g on lifting days. I just started today, so I guess we’ll see what develops over the next few weeks/months. Any more advice on the topic from anyone is welcome though =)

        1. You can see on my about me page that my physique has benefited nicely from 350 grams of carbs during refeeds.

          I usually workout on an 8 day week, so I workout 3 days and do 3 refeeds every 8 days. If I need extra rest I’ll push it to a 9 or even a 10 day week.

          I write in some detail, and give tips on carb refeeds on my website.

  6. i have been doing lean gains now for about a month, its been working well but i like the idea of it being 10/14 for women i am going to give that a go, although most of the time i am fasting 16 /8 anyway!

    thanks for this i am going to experiment as i like the idea of ustilising the natural need for food as a fast and a way of loosing fat

  7. After reading the first part of the why fast series I started fasting. I was doing a Brad Pilon style or alternate day type fast. Basically, on Sunday, Tuesday and Thursday I only eat supper. A normal sized supper not a big feast. This gives me around a 20 to 24 hour fast depending on when I ate supper the night before.

    This has worked for me and I have lost 2 to 3 pounds each week since. Now, I have been having two coffees with cream during my fasting days adding up to probably 75 to 100 cals spread over the day during my fast.

    I’m hoping even though I do that I still get some of the other benefits Mark has pointed out in his posts on the subject.

    Thanks for the interesting series of post Mark and for inspiring me to give it a try.

  8. Since switching to paleo, my kids (girls, 9 and 11) often skip breakfast and or lunch. It’s totally up to them. I just tell them to eat as much as they want if they’re hungry and not to eat if they are not hungry. When they say they’re not hungry I don’t make them eat.

    Back when they ate a normal breakfast and lunch, they would want a snack as soon as they got home from school. Now they have more energy and spend a lot less time eating. No lack of calories as they can eat a 1 pound New York steak with butter on top plus veggies grilled in tallow for dinner.

    1. Bravo to you! If more parents did this kind of “food parenting”….we would not be raising a generation of sick, overweight kids.

    2. I’ve noticed the same thing with my kids, ages 4 and 6. CW tells us that small children have small stomachs and “have” to eat every couple of hors, so like most kids in their preschool, they ate breakfast, then a snack, then lunch, then a snack (or two), then supper and another snack before bed. Cutting the grains and loading them up on more eggs and meat, they might not ask for breakfast until 3 or 4 hours after waking. Then lunch is closer to when they used to have an afternoon snack. Supper is later, too. Snacks are rarely even considered. And they are still as energetic as ever (or even more so), are sleeping better (finally!), and are in the 90th percentile for height and 50th for weight. They have grok-let six packs and muscular legs that I covet!

      1. We certainly allow our kids to “self-feed” on the weekends and as best as possible during the week. They are 5 and 2 years old. They tell us when they are hungry and we offer food then. We also have bacon left on the counter and they grab what they want when they feel like it.

        It’s worked well so far. It also means we don’t have battles at the dinner table about eating their food.

        1. You can have bacon left after cooking it?!

          I started with cooking half a package at a time. None left. Then I started making the whole package. None left. Last time I made bacon, I cooked two full packages and STILL none was left when I went back to the kitchen. My husband and kids seem to think that wild scavengers will invade the house and take it or something, so they are sure not to even leave a bacon bit-sized scrap left!

    3. My hat is off to you.

      That is a great thing you are doing for your kids, probably less of hassle for you as well. Your going to have some very healthy kids.

  9. I recently began IF’ing — usually 16 hours, but did a 24-hr. fast the other day and it was pretty good.

    1. I can’t shake the idea that I’m messing with my metabolism. I can’t eat huge meals so w/2 meals per day I worry my calories are too low. Thoughts? I don’t want to be fasting and also undereating.

    2. How do I know I’m burning fat vs. protein, once my initial glycogen stores are used up? People talk of being “fat adapted,” but I can’t tolerate huge quantities of fat. (I don’t process it well; slow-emptying stomach.) Does my body go straight from burning sugar to fat, or sugar to protein? I couldn’t remember.

    Thanks in advance!

    1. Research shows it takes days of not eating food to slow your metabolism, and even then it isn’t as drastic as we originally thought.

    2. I think that depends on if you are keto adapted or not. If you are IF’ing in a keto adapted state, the rules do change and you should not be in danger of soliciting the starvation response. I have personally never tried IF’ing without being keto adapted.
      Protein does not actually burn well as a fuel, so you will go, I believe, from burning sugar to having to convert proteins (and some fat) into sugar to burn, aka ‘gluconeogenesis’. Unless you can become keto (fat) adapted, your body will continue to burn the sugar that it makes. In the even that you are not taking in enough calories, your body can catabolize a significant amount of your stored protein in this way (aka, your muscles).

      Your body does not automatically switch from burning sugar to burning fat… there is a period of time in which it makes the conversion. You will start producing ketones within days of lowering your carbs, however, this does not mean that you are keto adapted… keto adaptation can take weeks to occur. In some people it can take months. I believe it depends of your metabolic state.

      Have you considered ways of optimizing your digestion so that your stomach empties as it should?

      1. How do you KNOW when you are keto adapted? Is it a sensation? Are you just intuiting it? Do you do some kind of test?

        1. I take a shot at an answer.

          First, your diet should have shifted you over given enough time – no grain, low carbs to more fats, protein. That could take a month? I guess longer if you haven’t really gone into the optimal carb zone on the chart Mark publishes.

          Second, upon doing a fast how do you feel? If you have a ‘Carb Flu’, wiffy, headaches – then you are not keyto adapted yet. No problem, because the fast will actually accelerate your switch to fat burning.

          Personally the only discomfort I have during a IF or even 3 day fasts is cold hands; and even that goes away with some mild exercise.

        2. Ruby,

          There are tests for ketosis. Ketostix are a test strip you submerge in urine. If it comes out a purple colour then you have a reasonable amount of ketones in your system. These are not the best for accuracy, but typically you are only looking for a guide, rather than trying to work out the exact mmol.
          The better test is your blood and you can get home test devices for this that will to a finger prick test. These are very accurate.
          The other method you can use is simply based on what you have eaten over a period of time. If you have had less then 50g of carbs everyday for a number of weeks, it is highly likely that you are in ketosis… But not guaranteed of course. If you have had say 10g of carbs per day for the same period the odds are greater.

      2. Interesting; thanks for the replies. I take digestive enzymes with meals to help with stomach emptying, but sometimes I just think I do better on a moderate (vs. high) fat diet.

        I haven’t been consistently “paleo” for very long, but I feel fine during fasts, so I’ve really no idea whether my body is using protein or fat for energy. Hm.

        1. Okay… on “ketosis” – I ordered a version of ketostix online… actually, something that’s supposed to test for a bunch of stuff… so we’ll see.

          I get a little frustrated when I see stuff like, “you just know.” No, you don’t just know. If you’ve never been in ketosis, how the heck would you know? “Carb Flu” is also a totally subjective thing. People who have been consuming allergenic type food their whole lives have been known feel instantly better when they quit wheat and dairy. So where is their “carb flu?” Most of us probably lived our pre-paleo version of life life in some version of “carb flu” by virtue of having crappy diets. “Carb flu” is as vague a description as saying, “you can feel ketosis.” I’d love some hard evidence on both of these states and if a urine or blood test is the only way to know for sure, then I can accept that.

          As for people talking about how many grams of carbs you eat… this is crazy talk. Sure, Mark talks about staying under a certain number of grams per day, but come on. Do you have a scale that you weigh everything on? No! The whole point is NOT to have to weigh food or count calories (which cavewomen didn’t do!) Foods don’t come in neatly packaged macro-nutrients. The concept of macro-nutrients is so totally over-simplified. Foods are combinations of nutrients. Almonds contain carbs, fats and protein. So… if you toss a couple nuts on a salad, add some bell pepper and maybe something else that’s not a PURE protein or fat, how can you really know if you’re eating less than 50 grams? Sure, one could just eat eggs and steak all day for a month to guarantee ketosis, but I don’t think Mark, Robb Wolf or any other paleo advocate promote this eating lifestyle as it’s a) boring b) untenable in the social sphere and c) there’s lots to be gained from mixing up your diet.

          And… the fact that protein converts via gluconeogenesis to glucose makes me wonder about the tenability of getting into ketosis on a “pure” protein and fat diet in the first place.

          Give me evidence, or give me… cake? Right now, cake sounds really effing good. Oh, right I must be in carb flu.

  10. great article.
    Is a TBS of butter/heavy cream in coffee considered breaking the fast? Seems to be a few different opinions on this in the paleosphere and curious to get your opinion.

  11. I do sort of a combination between the LeanGains and and Warrior Diet. I work out in the afternoon, and usually go straight to cooking dinner. I eat slowly until I’m full, and if I get hungry again before bed, there’s usually some leftovers. The only time I drink coffee is before a workout, but I don’t do any of the BCAA or other pre-workout supplements.

  12. I’m somewhere I suppose between the Eat Stop Eat style and the Warrior Diet. I fast currently two days of the week. Having my last meal sometime between 6-9pm and then not having anything until the same time except for usually a small snack at 4-5pm when I get home while cooking dinner.

    I run (usually HIIT/Sprints) on the fasting days around 1-2pm in the afternoon.

    I’d also say my main motivator at this point is weight loss rather than the other benefits.

    Also as a former fat guy who could set his clock with his stomach there is something strangely empowering about being able to skip eating for a day without hunger pains.

  13. I started IF about two years ago. I started with the WD method because it was the easiest and most natural for me. I loved the expressions on people’s faces when I had to explain to them my first meal of the day comes at sundown (no it’s not Ramadan and no I am not Muslim). In summertime here in MN that can come as late as 10p.

    Now I just eat WHEN. I do Crossfit and sometimes I do it fasted and sometimes I eat a small portion of protein beforehand. It just depends on my energy levels that day. I also am experimenting with post workout fasting for up to 3 hours after training. No sweat. I feel great and it is nice not having to plan meals all the time.

    The real benefit comes on those days when I am out and about all day long and have no need to stop and find calories. This bewilders most of my friends who cannot comprehend my “madness”.

    1. Hi,
      I am with you on the WHEN approach, my hubby and I employ it all the time, and it is working for him even though he isn’t completely with the program. After decades of the conventional approach, it’s so liberating to have such a disconnect with food. If my day is busy, I simply don’t waste time eating. If there is nothing that I can buy to eat, I simply don’t when I am traveling. There is no guilt, no problem, and it’s so easy. I do try and throw in a longer fast every week, but generally eat only 2 or 1 meal a day. After a huge period of no weightloss, I am finally slowly shifting some again.

  14. I have the same question as Adam.

    I drink black tea with a tablespoon or two of coconut cream and 1 tablespoon of coconut oil Will this break or hurt my fasting?

    Either way, I know its alot better then the 2-3 donuts and drive through breakfast I use to get.

    1. I don’t think it really matters at the end of the day. Are you achieving your goals, if yes then don’t fret the small stuff.

  15. Would you still recommend fasting for someone trying to put mass ON (or at the least, not lose any kind of weight or body fat). I know fasting doesn’t necessarily mean less food, but if I wanted to fast solely for the disease fighting reasons, would you recommend it still? What are some ways to ensure no mass is lost? Also, does having say cream in your coffee in the morning negate any fasting benefits? Any opinions are welcomed!

    1. Katie, read the LG’s website. As the name of the program is “LeanGains” you’ll see Martin’s recommendations for IF while retaining and even gaining mass. All it takes is a couple looks at his photos to realize he’s not losing mass. His basic premise is to eat a large post-workout meal and if you train in a fasted state to supplement with BCAA’s to help with protein synthesis.

      While he doesn’t recommend a Primal diet, there’s nothing to preclude it if you don’t mind getting a few extra healthy carbs here and there.

      As to your cream in coffee question – I’d say it’s not ideal, but if you use a small amount of heavy cream (say less than 20-30 cals worth) then it probably won’t have much affect.

    2. It is hard to gain weight, or eat enough, while eating whole foods and following a daily fasting protocol. Just keep your eating window big enough, so you can get enough food in.

  16. After trying EatStopEat and Martin’s method, I’ve come to the same conclusion as Mark – mix and match, and do what works with your life. I’ve settled on skipping lunch, with a some 24 to 36 hr fasts mixed in and had good results. It broke my weight loss plateau and I feel a lot better than constantly being in a fed state. But, a word of warning … Do it for at least a week, because the first week is BRUTAL. I know it’s different for everyone, but it was really, really hard for the first week, then like switch, it turned out to easy, like second nature.
    I also think you should not try IF if your diet is out of whack nutritionally. I’ve tried IF in both states and I think the hunger is different (worse) if you are nutritionally deprived.

  17. Great post. Really puts things into perspective. I’m a total Eat-Stop-Eat-er. (And I’m actually fasting right now)

  18. Since switching from a high carb, whole grain, and low fat diet, I have frequently found myself accidentally in the middle of an “eat when I’m hungry” fast. It feels great and I don’t waste time eating meals I don’t need. However, because I am very active, I have recently been trying the leangains approach. It seems to work well and my workouts don’t suffer, but I tend to think about the fast too often. I don’t want to stress about eating an hour early once in a while, so I’ll probably stick to eating when I’m hungry.

  19. I’ve loosely followed LG’s style, but have an erratic workout schedule so one day I might train fasted and the next not. This makes it a little more difficult to plan the post-workout meals, but I try to maintain an approximate 16/8 eating schedule, cutting off around 8 or 9 pm. Recently I purchased Eat Stop Eat, and have started incorporating 24 hour fasts once or twice a week, usually on my rest days (basically extending my 16 hour window to dinner). One thing I have done is taken Martin’s recommendation of BCAA’s prior to a fasted workout. He seems to have done his research and is adamant that the effect of BCAA’s pre-workout is crucial to protein synthesis and overweighs the effect of any negative effect to the fast.

    A couple of things I’ve noticed: Many of our hunger pains are psychological and can be solved by drinking more water, coffee, etc. Once you’ve become accustomed to fasting, you’ll know when you are really hungry and hunger pains will usually subside pretty quickly. Calories still count – just like in a completely Primal diet, calories will always count, so don’t gorge after a long fast. This defeats the purpose. Don’t go into a fast unprepared – if you’ve binged on sugar, alcohol, lack of sleep, etc the day before, a 24 fast is probably not your best bet. I usually don’t have a problem skipping breakfast, but would eat normally from lunch on then start a fast the next day. Similarly, don’t workout in a fasted state after an unhealthy binge session the day before.

    The great thing about IF to me is relatively easy fat loss while also not having to worry about so many meals. This saves time and money and frees you up for other things. I used to be one of those that ate a big breakfast each morning, brought enough food to work for 2-3 snacks plus lunch, and cooked dinner eat night. The only thing is I never was fully satisfied, and always felt “hungry.” Mostly this was because I was bored at work and couldn’t wait to have some more smoked almonds, or eat that big ass salad, but now I don’t have to worry about that. I pick a fasting period and stick with it usually. I don’t think at this point I could follow the WHEN method though, since I still get a lot of false hunger signals and would be eating all the time again. Now I can tell how hungry I really am because that same salad fills me up for hours after a 16 hour fast. Another huge bonus for IF for me is the ability to keep away from office sweets. Previously if I were eating throughout the day, I’d have a sweet because “just one won’t hurt” but then often I’d go on a binge. Now if I’m fasting, I don’t have the urge as much to cheat because psychologically I know I’m in the middle of a fast and don’t want to break it for some crappy donut or cupcake.

    1. Ditto. You just described me exactly. My eating window is a bit earlier in the day than is typical (because I want to avoid snacking at work where I’m surrounded by food) but I have no problem going to bed hungry and not eating breakfast until about 11 in the morning, regardless of when I wake up. I’ve never had that sort of freedom from food. Was a constant grazer, and was never satisfied by anything; I was always thinking about the next thing I was going to put in my mouth. Not anymore! I haven’t tried any 24 hour fasts but I think I’m going to start throwing one in between the 16/8 days. Can’t wait to see what impact it has.

  20. Ok…so I really like the idea of WHEN fasting (I pretty much do it already anyway). But sometimes I’m truly hungry fairly often, even when I think I shouldn’t be (like on lower activity days). Anyone have this issue? Should I just eat…or wait it out until I’m hungrier, considering that I’m not expending much energy? Anyone feel like they have some insight for me? Thanks!

    1. I maintain a high appitite on my rest days because of the workout the day before. I have always been that way. I actually don’t eat as much on workout days because the workout kills my hunger, but the next day, look out. I think it takes time for some people to refuel the system after a good workout.

      Also try to drink more water and get out and walk, that will take care of the hunger too.

      1. i agee – remember that your body builds up/repairs AFTER you work out. you need to fuel that recovery with good food.

  21. I do better with an evening fast: breakfast 6 am, lunch at 11:30, bulletproof cocoa at 2 pm, only tea after.

    1. I have heard of bulletproof coffee but not cocoa. Would you share your recipe? It sounds good.

  22. Thanks for this series, Mark! It’s been great.

    I’m a fan of the Leangains protocol. I train 3 days a week (Squat/DL, Bench, Chins) generally in the morning around hour 10-12 of my fast – I then continue the fast to 16 hours. Ideally I’d be lifting closer to hour 16 but I work 7-4 and this is the best I can do without shifting my eating schedule to not include the standard dinner hour and I’m just not willing to do that for a few reasons.

    Even so, I’ve had great success using Martin’s recommendations. I definitely consider myself to be someone trying to put some weight back on after losing much more than anticipated following a standard Primal/Paleo life for the past 8 months or so. Not a bad result, just a shock that there was that much fat and that little muscle. After going from 215 to 165 in those 8 months I’m now just over 170 after about 3 months using the Leangains guide for IF and training.

    Tried the 24 hour fast a couple times. Didn’t mind it but prefer the 16/8 method much more. Found myself thinking too much about where I was at with the 24 hour method. In a good groove w/ 16/8 and have no intentions on changing it.

    1. We’re following a very similar eating/training/workout schedule and I’m wondering if you’ve been using BCAA’s as per Martin’s guidelines?

      1. Yes I am, Mario. Whenever I train in the morning during the week I follow Martin’s early morning fasted training protocol pretty closely. Usually 10g ~5:30, another 10g around 7:30, final 10g around 9:30 and lunch @ 11:30.

        Often I will have a workout on the weekend and I will wait to go in until I’m at 16 hours and will just do the 10g pre-workout, come home and eat.

  23. I have been loosely following LG’s, also (typically 17/7, skipping breakfast). I love the fact that I don’t have to “worry” about eating breakfast & am no longer longing for snacks in between meals. It has also helped with staying away from “treats” at the office. And, once 7pm hits, I know that my fasting period has started, so this has helped with late night snacking.

  24. I haven’t yet experimented with fasting. I typically eat breakfast/lunch/dinner and a late afternoon snack. This article reminded me that I’d like to increase the gap between dinner and breakfast – if I eat dinner a little earlier, I can come close to fasting, and might also be able to skip my pre-dinner snack.

    I like the idea of eating when hungry (isn’t that the purpose of eating afterall? :p) – and it goes hand in hand with mindful eating. Especially on weekends, when I can eat whenever, I try to remember to only eat when I’m actually hungry, rather than just because the clock says it’s mealtime.

  25. Today I will begin my yearly 2-week fast. I am very attuned to fasting and have near-miraculous results afterward…always. Wish me luck!

  26. I did ADF for a year. But I’m trying something different now. Mondays, Wednesdays and Fridays I eat one meal a day. This is a gigantic salad at around 6pm. I don’t eat any animal protein with it (just nuts, seeds, etc.) and I drink my coffees black. The rest of the days (except sometimes Saturdays, depending) I eat three meals and two snacks. All the meals have animal protein (grass-fed beef, elk, wild salmon, really good eggs, etc.) and I put heavy cream in my coffee. This gives me a 24 hour fast 3 days a week (sometimes on Saturday, too) and I’m finding it really easy. I’m thinking it’s simulating the days Grok couldn’t find anything to hunt. 🙂

  27. I have really enjoyed basically doing the Warrior Diet. I don’t eat anything all day, black coffee in the morning when I wake up. I work out around 3:30 or 4:00 and then its dinner and maybe a snack late night. But I have always wondered if I am doing it correct. Am I eating enough? When you say “feast”, what does that entail?
    Example: Coffee yesterday morning, nothing all day. No workout, and then had a large bowl of steamed shrimp and broccoli. Not a struggle to do but want to make sure that I am not hurting myself or setting myself up. Thanks for any help and support.

    1. I eat pretty much the same way (Warrior Diet) with the exception that I have daily my cup of coffee with extra cream in the morning before my workouts. I work out in the mornings (kettlebells and rowing) and I don’t eat till dinner. Been doing this since January and it has become like second nature.

      I’ve never really “feasted” as I’m just never really that hungry even with daily fasting. In addition, there is only so much meat and vegetables I can eat at one sitting, and I eat till I’m full. I feel extremely good so far, so whether I’m eating enough or not doesn’t make much of a difference to me. I’ve found something that is easy for me to do and and sustainable with the added benefit that I feel great everyday.


  28. Sleep and training schedules are important ingredients to success when implementing LeanGains.

    Not every plan/recipe works for everybody. We’re all wired differently and lead different lives.

  29. I do have a question if anyone can give me some advice. What do folks do about supplmental vitamins during their fasts? Take them as usual? Wait until they eat?

    1. I can’t take my vitamins because they give me a reeeally upset stomach without food, so I just skip them… except for vitamin D.

      1. in the summertime (depending on where you live, maybe all year..) you can get Vit. D by spending time outside with your skin showing!

        1. Not so much if you live in New England and work in an office. Even mid-day mid-summer, the angle of the sun isn’t great for getting your Vitamin D. And the sun’s too low in the mornings and evenings, when I’m out in the world during the week, to do me much good in terms of Vitamin D.

    2. Most vitamins & supps suggest to take with food, so I wait until a meal (I IF @17 hrs daily)

  30. I go with WHEN, because I am already naturally thin and worry about losing weight, so I eat when I am hungry. Even still, I typically go about 12 hours a day without eating, and every Saturday I don’t eat my first meal until around 2:30, 3 or sometimes 4 in the afternoon because I am usually not hungry before then.

  31. I tried to fast for 24hrs in January after going through a food overhaul during the holidays. I did it Eat Stop Eat style after a friend of mine recommended it. I was in a haze, couldn’t focus, felt sick and only made it to 22 hrs.
    After Mark’s IF series, I decided to try again since I’ve been eating Primal for about a month now. I have to say it was SO MUCH easier. I did not feel any effects of the fast and felt that I could go on longer.

  32. Mark,
    Thanks so much for this summary, perfect timing actually! I’ve been reading up on fasting methods since you first introduced the “Why Fast” series. I found that 16/8 is the most natural fasting period because I’m not really a breakfast kind of girl. However, I’m not eating a feast for dinner as described in Leangains because I can eat that must after working out and I’m not interested in becoming too muscular, just lean and toned.

  33. I pretty much eat when i’m hungry, like the last one. Sometimes that can be one meal a day, sometimes it can be three. Sometimes nothing until the next day. I’m rarely hungry in the mornings, anyway.

  34. I have been using Berkhans form of fasting since Jan 2. All i can say is i am blown away by the results. I have lost 35lbs, and i can confidently say it is almost purely bodyfat as my strength has gone up immensely. My deadlift went from 245lbs for 6 reps to 405lbs for 6 reps. Bench, squats and chins have all increased by quite a significant margin as well. Im sold, i will eat this way for the rest of my life. It really has changed my life.

    1. Hey Kyle,

      Congrats on the results man! Good for you! Hey so, earlier in the comments section of this post, I asked a question about grams of carb consumption on lifting days. Do you follow Mark’s refeed recommendations of 250-300g? Do you follow something else? Are you doing the LG approach within the Primal guidelines?

  35. I’ve started combining Alternate Day Fasting with the “Warrior Diet” eat once a day thing in a limited window. For one day I don’t eat (I might have heavy cream with my coffee and about 8oz of plain kefir or yogurt mixed with cream in the afternoon if I’m feeling really hungry but no solid food). The next day I only eat within a 6 hour window.

    The nice thing about only eating once a day is I don’t really have to count carbs as carefully. I still avoid grains, sugar, potatos etc, but it gives me a little more wiggle room.

    I can’t really do the eat when I’m hungry thing because if it was up to me I’d eat like 6 times a day. I have been Paleo for over a year and even with working out I have not been able to drop more than about 10 pounds. I started using IF to break that plateau and dropped 5 lbs in the first week. I have already dropped from 225 to 165 in the past 2 years! This last 30 lbs has got to be the most stubborn!!!!!

  36. Good results and feel awesome on this schedule: 2pm-8pm eat; coffee with coconut oil and grass fed butter on rising about 6am ish. 24 hour fast on Monday from Sunday dinner to Monday dinner and a “normal” Saturday to not stress out the kids!

    1. I do almost the exact same thing, including the 24-hour fast on Monday. The BP coffee tides me over until after lunch and tastes so good.

      However, I do wander whether BP fasting really does preserve all the fasting benefits. Who cares? Seems to work for me.

  37. Great series Mark! It has inspired me to jump into the realm of intermittent fasting. I’ve taken to the 24 hour fast. Eat a normal meal for dinner (by 8:00 Pm) then not again for 24 hours. Suprising how easy this is now that I have switched to Primal. I used to be a total carbaholic, couldn’t go more than 2-3 hours without eating something or I’d go hyper-glycemic.
    Thanks for all the information on your site, it’s really helped me to remain focused and committed.

  38. I prefer the 16 hour fast and eight hour eating window. I like being in the fed state less for less digestive stress and I also love training fasted. My sleep, workout performance, and digestion has all been improved from this style of fasting.

  39. I’ve had the most luck in skipping dinner, and not breaking fast until the next dinner or even breakfast. I feel like I sleep through the hungriest part of the fast, the 8-12 hour period. After that you can either eat or not, and your body doesn’t much care.

  40. I have been interested in fasting for a while now. I could use some advice…if some one could tell me the best type of fasting for weight loss while maintaining muscle as best as possible. The most important thing for me right now is the weight loss. I do have quite a bit of weight to lose and have no trouble fasting. Thank so much.

    1. My primary goal is fat loss, and I’ve got a long way to go before I get to it. The best method for me has been to get keto-adapted (very low carb) and then skip meals until I can’t anymore.

      Basically this equates to Eat Stop Eat – Once or twice a week I do dinner one night, then nothing at all until dinner the next night. (I do sometimes have coffee with cream during a fast, but only one and only sometimes; usually I just stick to black coffee or tea.) I get a kick out of the headspace I get into when fasting – it’s like exercise for your willpower, and it seriously boosts my confidence and sense of well-being. Ignoring the mild hunger pangs I usually get around 11:30am and again around 5:30 or 6pm and pushing through makes me feel strong and in control of myself. It also helps me distance myself from the intense guilt I used to feel whenever I ate anything; it’s very hard to feel guilty about eating when you’ve fasted for 24 hours. That’s helping me readjust my feelings about food even on non-fasting days.

      Long story short, as a long-time fat chick who’s finally found the right path, I like the 24-hour fasts for the emotional benefits as well as the physical ones.

      Physically, I always drop fat-pounds after a fast. Looking back over my journal, I’m doing pretty well at around 8 lbs down a month while maintaining my strength, energy and mobility. I don’t feel tired or sluggish during fasts, though like many others, my hands do get cold toward the end. And I find that even when I do get hungry on a fast, it’s only for a few minutes, and it’s easy to push it aside.

      I worked my way up to the 24 hour fasts by skipping breakfasts, and then later I started skipping lunch as well. It’s amazing how freeing it is not to have to be cooking or thinking about food, what to pack and what to bring, every single day. I’m working my way up to trying a 36 hour fast – but I think that’s going to be harder than the 24, so I’ll have to see how that goes.

      Hope this helps. 🙂

  41. I’ve been experimenting with fasting for about two months now. Here’s what I do: skip breakfast every day. Drink tea during the morning hours, water after that. Sometimes I have a cup of coffee with a small amount of heavy cream. Eat a small lunch. Eat a larger dinner. No snacking. Then on the weekends I only eat once per day and it’s at about 5:00 or 6:00. I lift heavy three times per week and go for short walks every day. I do some HIIT as well. This has worked quite well for me. In addition to better fat loss and body composition I have enjoyed increased energy, mental focus, and an excellent mood. I must be fat adapted because I rarely experience any hunger at all during my fasts.

  42. I got my feet wet with Art De Vany’s skip dinner once a week fast. which is very doable. then tried longer wait till really hungry style fasts.

  43. I’m doing Warrior diet for about 8 months now.
    Or something close to it, because I don’t really stress out about it and sometimes “cheat” (well, I actually do that about every Saturday when I visit my grandma!)
    I have no wish to change my eating habits because IF gives an incredible sense of freedom, with eating only when you want, not stressing about meals (or their absence)

  44. Firstly I’d like to say I’m primal in the UK and loving it! I sometimes do Eat WHEN, but lately I have been doing the EAT STOP EAT when I fast for 36-38 hours and I never feel hungry. I exercise regularly and hope it will help me to lose some weight.

  45. Last September/October I experimented with the Leangains method (mostly 16/8, sometimes 14/10, I’m a woman) for about 6 weeks. The fasting was the easy part, it was the scheduling that was hard! This was especially the case on weekends or with friends in town as it meant I had to adjust my feeding window, which I don’t like to do. Eventually, I abandoned the method because the scheduling was causing me a lot of stress.

    I’ve also experimented with a handful of 24hr fasts and find them to be pleasant, provided I don’t try to workout strenuously.

    Lately, I’ve done a 20 hour fast most Tuesdays (last food at 1pm, then only coffee/tea/water until 7a the following morning) because it’s more convenient to fast than eat thanks to my schedule on Tuesdays. This has worked better than any other type of fasting I’ve tried.

    For reference, I’ve been eating primal for over a year and have few to no problems with brain fog, dizziness, irritability, etc while fasting.

  46. I’m definitely a WHEN eater. My husband and our little boy are too. We don’t stick to eating schedules; we eat when we’re hungry and stop before we’re full. And I don’t eat between meals or after dinner. Often times I won’t eat from dinner (7:00 pm) until 10:00-11:00 the next morning. I feel great! And I am a pre-dawn runner/weightlifter and have no workout issues. WE LOVE PRIMAL!

  47. I occasionally fast 24 hours or one day (Eat Stop Eat). It has been easy from the start. Even the first time I only was a little hungry.

    I do get cold hands or even cold feet in winter at the end of the fast. One solution I found is to go for a long hike at the end. Does anyone have any other ideas how to combat cold hands while fasting?

  48. Have fasted 36 hours once a week for 1 year and 4 months now. On non-fasting days I observe a 16 hour fast … so in fact I am fasting 6-7 days a week. Now I understand why fasting is a part of every spiritual/religious tradition. Watch scientist Rupert Sheldrake on fasting: https://www.youtube.com/watch?v=m4L5QKsrGlY

  49. Hi guys, Ive been a lurker for awhile. I fully believe in Primal, but I have hit some bumps in the road. I was always in great shape, I am a medic who was in the process of joining the fire department. I badly hurt my back and I’m unable to do anything I used to. I can walk, but that is about it. I used to lift weights, bike, golf etc. I have gained 20 lbs over the last 1.5 yrs while off work. Both times I started primal, I saw immediate results. The issue is I am on a tight budget and fall off the wagon by eating bread and pasta cuz it is cheap. Any ideas on how to stay consistent due to my budget and keeping my food from getting boring? Thanks for listening.

    1. Ray, There are a lot of articles here on Mark’s Daily Apple and on PaleoHacks that can help you with being on a budget (fasting helps the budget also!).
      Have you looked into Tai Chi? The gentle movements might be an exercise you could do.
      Hang in there!

  50. I’ve adopted the Leangains 16/8 fasting method for months now and it works perfectly for me. I work 3-11pm so that frees up my mornings. I workout in a fasted state and I never feel tired or lightheaded or anything but energized and alert.

  51. Personally, I have used Eat Stop Eat for years and even recommend it to my weight loss clients. In the fitness industry it is well renowned as a highly effective weight loss tool. I feel that Leangains is great, except it caters to Meatheads. 🙂 Hope that doesn’t offend anyone.

    In addition to that, I have stopped eating breakfast if I’m not actually hungry and generally end up feeling like I could use something around 11 am.

  52. Ok, so what about all of us people with regualr day job hours? I mean, I can’t work out at noon or early afternoon – not gonna happen. I can work out/exercise after work 4-5ish or so. For me it is easy to skip breakfast, but I love lunch and dinner, so obviously I would not be working out fasted at all on this schedule. The only way I can see this working is for me to eat dinner and breakfast and not eat all day, and honestly, that is probably going to cause me stress… How do all these MDA readers get to work out during the day all the time???!!!

    1. I was thinking the same thing! How awesome would it be to have the time to work out at noon. In the sun. before lunch. outside. *sigh*

      I mostly just skip breakfast a few days a week. Some days I’m hungry in the morning, some days I’m not. Some days I’ll eat a late breakfast at 9:30 or 10, some days I’ll just start with lunch at 12 or 1.

    2. 9-5 job

      You choice is to work out before breakfast, or skip lunch, and then workout and then eat in the evening.

    3. On the LeanGains site he has different options depending on when you can workout. I work 9-5 so working out during the day is just not going to happen, so I follow the plan under the heading “two pre-workout meals”, which is the one he recommends for people who workout in the evening. You’re not working out in a fasted state, but it doesn’t really seem to matter.


    4. I don’t actually work out at all. That makes timing my work-outs extremely easy! =D

      Actually, I lie – I do sit on an exercise bike during Castle or Person of Interest or whatever I happen to be watching, a couple of times a week, and pedal at a random (but generally easy) pace. And I do have to walk about a quarter of a mile to and from my parking space to my office every week day, and do a good bit of moving around in the office at work.

      The only strength training I get is from picking up and hugging my cat, and he gets really skinny in the summers, so I doubt that counts. 🙂

  53. I am at the tale end of my first fast! Once I’ve eaten dinner, it will be about a 23 hour fast. Pre~Paleo, I never could have managed. I would have been cranky, shakey and had a major headache. Today, I’ve been fine! I did a ton of yard work and still feel great. This has made me very aware that I’ve probably been eating when I didn’t really need to. I will definitely be making this a regular occurance assuming I continue to feel great doing so. Thanks so much for all the great info!

  54. “Most people begin their fast after dinner (say, 9 PM), workout in the afternoon (at around 12 PM), and break their fast immediately post-workout (at around 1 PM), but you can use any schedule you prefer.”

    Yea, Most people with no jobs..

  55. I’ve done about three fasts, mostly after a big lunch makes me feel bloated and not eating til lunch the next day seems like a good idea.

    I’ve found that it works much better after my usual high fat/med protein/low carb meal. I tried it after my Sunday indulgence (sushi) this week, and I battled an empty, growling stomach for 24 hours. Yuck. That was too hard.

    After the first fast, I dropped 5 pounds that stayed dropped. The second two fasts haven’t had any weight losses. 🙁

  56. How does this work if you are a exclusively breast-feeding mama? Will milk production decrease? Would this just not be smart to do while bfing?

    1. I suspect the WHEN method should be idea. Eat when you’re hungry. Breastfeeding pulls a lot of calories and nutrients from the body, so I imagine you’ll have a higher baseline of hunger and the desire to eat more frequently while breast feeding than after weaning. But if you’re not hungry, I imagine it’s because your body is still nourished enough not to require more at that moment. Trust the wisdom of the body unless you have reason to suspect it is broken, or that the signaling mechanism (which is what hunger signals are) are out of whack for some reason.

  57. I know we shouldn’t fast when stressed, but seriously I think the fasting is helping me deal with stress, as I feel so nicely calm and content during.

    Discovered if I fast in the evening of a day when I’ve cheated a little and raised my blood sugar/insulin, fasting is hard work – I’m hungry constantly and feel a bit cold.

    If I’ve kept to primal principles and eaten properly, fasting in the evening is a breeze. No hunger, feel warm and sleep like a baby. I think there’s a lesson here!

    1. I have struggled with anxiety/OCD for years… have been off and on medication for it. Currently off and finding that fasting helps a TREMENDOUS amount. 22 years old and never really had weight problems but started a primal diet a year ago to try and help with my anxiety. I know that when in a fasted state I feel MUCH calmer.

      1. Don’t say that too loud!!!!

        The drug companies will have you knocked off!!!

        I agree, my mental state has been much more calm since Paleo and IF. Wish I new this when I was younger!

  58. I most closely combine Warrior and ADF. I eat the big meal in a small eating window of Warrior (minus any snacking in between) PLUS I only eat said big meal about every other day, like ADF.

    I find either alone is not enough fasting for me – eating daily in any sense isn’t fasting for my metabolism. Eating all day every other day isn’t enough fasting for my mtabolism. Eating in a small window, every other day, is JUST RIGHT. 🙂

    Note: I eat (in a small window) both Saturday and Sunday each week – I am always grateful for my fasting day on Monday, but by the weekend, I am ready for my back-to-back eating days, so I know I have found a good balance.

  59. Count me among those who hasn’t seen much success (body composition-wise) with any sort of fasting. I blame either lack of sleep (I average 7 hours a night), overcaffeination, or chronic anxiety. I’d guess that fasting goes well for those who already have a relaxing job, get enough sleep and are not hopped up on coffee. Stress on top of stress on top of stress is unhealthy.

  60. Warrior Diet has always worked best for me, I do some 24-36 hr fasts every few weeks but as a daily plan- Paleo and Warrior is a perfect fit.

  61. Eat Stop Eat (once a week) works perfectly for me. The fasting day is Tuesday (like today). As I am typing this I ate last night at approx 8pm, it is 6:40pm and I have not eaten anything yet (will do soon, Primal Meatloaf beckons)

  62. Great post thank you!

    I’ve just started experimenting with LeanGains type of fasting and have had no issues with it at all, which is amazing to me, as I’ve always been someone who “must” eat breakfast otherwise I would get cranky and feel sick from being hungry.

    I still feel hungry when fasting (I’ve only done about 3 so far I think), but I seem to get over it at some point and then don’t really think about food at all, which is great.

    I’ve been paleo since November, so I guess I must be pretty much fat-burning adapted now and I don’t get cranky or feel sick from hunger. It’s really good as well because now I know that if there is only crap food available, I can just not eat and I’ll be fine!

  63. As someone who tends to overeat in the evenings, I wonder if I could make Berkhan’s formula work simply by skipping dinner.

    I could eat breakfast at 7:30, eat lunch at noon and have a high-protein snack at 3 p.m. That would leave a 16-hour window between meals.

    Somehow, this almost sounds too easy. I would still be eating almost as much food as I do now, but just timing it slightly differently.

    My goal would be to lose body fat while adding some lean muscle. I would work out in the mornings — although I don’t know if I would be too hungry to do it before my first meal of the day. I also don’t know if I’d be too hungry at night to sleep well. (On the other hand, it might encourage me to go to bed earlier.)

    Any thoughts?

    1. Many people on LG who prefer to eat at night seem to simply have a late dinner. For me I had to get my snacking under control before I could fast comfortably.

      If you read Berkan’s website he does try to fit his program around the schedule that works for the client. A lot depends upon flexibility in the timing of workouts.

  64. I do the 14/10 style and its a breeze. If I DO have to eat breakfast early when I don’t feel hungry (like this morning when my out of town father was staying and I couldn’t face the “you’re not eating and looking after yourself speech”), I seem to set myself up for a much larger eating day, despite my breakfast being bacon and eggs. Any thoughts?

  65. I am very new, I just went low carb last week but I am now questioning my hunger every time it comes to the traditional meal times of breakfast, lunch and Dinner and so far this week I have skipped at least 1 of them, if not 2 with ease simply because I wasn’t actually hungry. This is so liberating, how many times have I been doing something and stopped everything in its tracks because it happened to be 1pm or 6pm.

  66. I’m having trouble finding the answer to this question:

    On Leangains, how long are you supposed to stay on it? I understand the word intermittent is built in but how long are you supposed to sustain the fast?

    Thanks, sorry if I missed the answer to this. I’m not exactly tech literate.

    1. The fast is 16 hours daily (14 for women). The way of eating can be done indefinitely. I will never eat another way other then IF.

      1. Thanks. I understood the daily part but I didn’t know how often or for how long (ie: days, weeks, months, etc). I was confused because it seems like the PB way is actually intermittent. Occasionally skipping meals, etc.

  67. Ok, so I have to wonder if this is the same for men and women. If you think all evolution-ish, wouldn’t women be by the fires, close to home, making meals, gathering, etc., and not necessarily going for a long time between meals? Also, women would have been pregnant or breastfeeding pretty much their whole lives, so wouldn’t fasting make less sense? I get hungry less often now, and it definitely doesn’t bother me so much, but I can’t imagine going for 10 or 24 hours without eating, especially since I’m responsible for my two kids.

    1. Hi Christina,
      I have had the same thoughts as you. I’ve done Leangains twice now, once for several months and once for 6+ weeks, and it has made me very bingey both times. I have wondered if this is a woman thing as most of the people I know or have read who have tried it and liked it are men. In addition to making me want to binge, I haven’t seen any change in body composition and have usually gained a bit of weight, despite having lower calories. I really WANT to believe it works, especially since it seems to work so well for other people, but I seem to do better as a grazer with occasional long fasts thrown in rather than trying to do 14+ hour fasts every day. From the reading I have done, I have came to the same conclusions as you about women likely being back at base camp, picking berries and preparing taro root, eating more throughout the day, and more carbs/leaner protein than the men typically do. Now I am starting to experiment with that sort of eating, trying to cater to whatever my own genes are programmed to handle most effectively.

      Interested in hearing others’ thoughts on this!

  68. I’ve found Leangains pretty easy to adhere to and it’s the only regimen that has allowed me to get shredded. I’m not hungry and don’t have the struggle I do when trying a 24 hour fast. For the first time in my life (I’m 53) I have vascularity on my abs, thighs and the love handles have disappeared. When I logged long hours and big miles as a serious cyclist, I never got this lean. This isn’t something I’m trying. I’m going to continue to follow this protocol for the duration.

  69. One would ask, combining the Warrior diet with Primal eating? Kinda what I’m doing now except I am restricting my one meal a day. I am intrigued by this Warrior diet…

  70. If I’m not doing any sort of lifting, but using several sources of low-intensity workouts, will I still benefit most from the LeanGains model for fasting? I want to lose body fat and gain tone up, but I don’t want a ridiculous amount of muscle mass. Aside from being a complete newbie to lifting and jot knowing where to start, I just don’t get enough sleep/have enough time for regularly scheduled lifting. I walk everywhere I go, have work 50+ hours during which I’m always on my feet and moderately active, and do yoga 4 times per week.

    1. Sorry for all the typos, my phone really doesn’t like to cooperate on MDA for some reason!

  71. There’s a great article about fasting that is the cover story of this month’s or last month’s Harper’s magazine. The author fasts for twenty days, I think, goes into the history of fasting. Anyone try an epic fast like that?

  72. I would like to get to about 12%-13% body fat. I’m estimating around 20% right now. Is my goal reasonable if I do a 24 hour fast once or twice a week?

  73. A year ago I tried Eat Stop Eat for about a month. I found it surprisingly easy, but it wasn’t quite right for me.
    I then tried LG w/BCAA’S prior to workouts.
    I have the best workouts. I recently ran 9 miles beginning @hour 14 of a fast. It went great.
    After a year, my body is used to not eating for 16 hours. It works for me. Thanks Mark.

  74. Hello everybody!

    A friend of mine occasionally does a fast where she doesn’t eat anything solid for three days, but she will have some shots of a high-quality fish oil and drink buckets of chamomile and ginger teas.
    She calls it an “anti-inflammatory fast”

    It seems to work for her, but would the fish oil slow down the fast? Does anybody have any opinions or insight on whether or not this is an effective plan?

  75. Is this type of protocol suitable for a 15 year old? my daughter has seen me do it and wants to join in I’m not sure if its suitable when shes still growing?

  76. Is there a minimum numbers of hours where any of the benefits of fasting kick in? Sometimes I’ll go 9-10 hours with out eating, but does this “count” as fasting?

    1. Over 12 is probably the bare minimum. Personally I wouldn’t call it IF if the fast is less than 14 hours. I wouldn’t call a “juice fast” a fast either. But the parameters aren’t specific.
      A grown adult with a healthy metabolism should be able to comfortably complete a short fast. I first had to lose some weight and become LC adapted before I could comfortably fast.

  77. This is an excellent review of all the popular intermittent fasting methods.

    I’ve tried both the Eat-Stop-Eat and the Leangains approach, but eventually I gravitated towards eating breakfast again and I don’t really “fast” anymore.

    But I do often skip breakfast if I’m not hungry or don’t have the time to cook my eggs.

  78. I started doing fasts only 2 months ago, i cannot get over the difference in how i feel and look. It has made me feel so much better, more positive and my depression has gone. I just can’t believe how good i feel now. I have always struggled with food cravings even on when following a low carb high fat diet, i always ate way too much and way too often, i followed atkins diet but i was not losing the weight like i thought i should be, but since starting IF (intermittent fasting) the weight is falling off me, and for the first time in my 37 years of life, i am not hungry / starving all the time, i feel i am in control of my hunger and not the other way round, i really think this is the key to success, i have so much more energy, am happier, my body feels leaner (not bloated like before), my skin looks better but for me the most important benefit is the significant improvement in my mental health, i was suffering bouts of depression and it has eased so much, i can’t explain it but it has! I eat at 8pm / 9pm and then fast til 8 or 9 the next day, if i am hungry at say 5 / 6pm i just have a piece of fruit, i also allow myself decaf tea / coffee with milk during the day (i just have 1 caffeinated tea first thing in the morning as it wakes me up) but no more caffeine after that as it was keeping me awake at night, but now i sleep like a baby, much deeper and more peacefully. I admit the first 2 fasts were kind of hard but your body will get used to it and your cravings and hunger will decrease dramatically. Thanks for covering this Mark, i feel like a new person. Good luck everyone!

  79. Mark, my friend has scleroderma, do you think Intermittent Fasting could help with her condition? Also can u recommend food / supplements she should take for this condition? She is on medication and has check-ups regularly but i would just like to see if there is anything else she can do on top of this that might help her prolong her life, she is only 38 years old and has 2 young kids, so any advise u could give would be greatly appreciated.

  80. Not sure I agree with the idea of the branch chain amino acids whilst/before training. As amino acids cause a release in both insulin AND glucagon, I feel they are simply confusing the issue. In addition, it is another supplement. The beauty of eating a primal diet, whether or not one is fasting, is that supplementation, especially ‘sports’ supplements can be kept to a minimum, as whole foods are the key to success.

    If you are adapted to shunt energy substrates to the formation of ketone bodies, then the amino acid toll on the body of fasting is minimal.

  81. Questions for next week’s Q&A:

    How much fasting is too much? Can (or should) you do Eat Stop Eat, the Warrior Diet or Alternate Day Fasting continuously?

  82. I have been following the Leangains program for several months and it has been successful in many ways. Recently, the constant, daily deprivation began to get to me, so I have changed things up a bit and have been trying several of the methods you discussed. I fast for 16 hours 3 to 4 days per week and I fast for about 20 hours 1 day per week. On the other 2 or 3 days, I do not fast and I eat more substantially (more calories). On a typical day, I don’t take in alot of calories, but several days a week now, I load up on them. This new approach seems to be working well and allows me the few days each week to feel thoroughly satisifed…and that usually results in “wanting” to fast the following day.

  83. I’ve naturally followed the WHEN plan my entire life. Funny, though, I never thought of it as fasting. People around me have commented on how weird it is that I “forget to eat.” They have it so ingrained that you must eat three meals a day (plus some snacks), that they can’t fathom how I’d “forget” to eat lunch with them or that I might not eat much of anything over a weekend. I even had a group of work friends decide that they needed to protect me from myself and each take a turn reminding me to eat during the week to make sure I didn’t starve.

  84. I have a ridiculously hard time waiting until I am hungry to eat. I just ate an apple while reading this article, for example, because it’s my lunchtime and I know I’m not hungry enough to eat my Big Ass Salad, but I still feel this urge to eat something that just won’t go away. I guess it comes from years of boredom eating as a child followed by years of calorie-restricted diets that tell you to eat 5-6 times a day whether you’re hungry or not. Its such a habit to eat at lunchtime that thinking about it will drive me nuts until I eat something even if I’m not hungry.

    My fiance has been an intermittent faster most of his life, first by necessity (his parents didn’t stock the fridge with anything but “dinner food,” as in, “you can’t eat that, that’s for dinner” food) and now by choice (“I ate a huge dinner last night, so I’ll just skip lunch and not eat until dinner to balance it out”). He rarely eats breakfast. I used to think it was just because he was more attuned to his hunger, but he explained to me about a week ago that he does it on purpose.

  85. I like the idea of intuitive fasting, but I think a regimented approach is good at first, because a lot of people have conditioned themselves to be hungry all the time, and something like Leangains or ESE is useful to get your body to acclimate to not eating.

    I used a week of leangains to get comfortable with not eating in the morning, now I eat more instinctively.

  86. Thanks Don. My issue is that I dont intentionally fast, as i am a competitive triathlete, but was just wondering if those occasional 9-10 hour periods of no food helped in anyway

  87. I 24 hour fast on Monday, Wednesday and Friday. I go dinner to dinner since that’s the easiest thing for me to do with kids. (since they’re in school and still get to eat) I have been doing it for just over a month now and love it. i get hungry around 10 or 11 AM every time but it goes away after about 10-20 minutes. I have lost 5 pounds. I am doing this more for my general health versus weight loss. I am eating better foods and not overeating. Love it!

  88. I’m so glad to hear that fasting is good. All the workouts and eating plans I’ve tried and all the health info I’d gotten said to eat every 2-3 hours to keep metabolism up. I wasn’t alway hungry but ate anyway. I practice the eatWhen type fasting now and I feel so much better. Rarely have I been “starving” and if I am, I get full very quickly and will usually not be be hungry again for hours. The eat every 2-3 hours was consuming my day. I had reminders in my phone when it was time to eat. Now I only think of food when I’m hungry. Thanks for the info, Mark.

  89. I have been fasting using the eat when hungry method. I lost 12 pounds during my 21 day transformation, then plateaued. Started a 3 egg breakfast at 730am, coffee at 11 am, primal dinner at 6 to 7 pm on non workout days. Didn’t really plan it, but that’s how my body felt. Not forcing lunch b/c that was my pattern of eating made a big difference. Lost another 5 pounds in two weeks eliminating those calories when I wasn’t hungry.

    I also travel for business and found I have no problem finding a place to fry eggs in butter for me (or poach) for breakfast, as I am always hungry in the morning if I dont over eat the day earlier. And I have found quality restaurants in ever city that I go to for dinner. I found that limiting ingredients while eating out for a week straight is the best way to avoid hidden calories. Example: Grill salmon (with directions to use real butter instead of oil) and steamed veggies. No fancy sauces, etc.

  90. I seem to do best with a 14 hr fast Mon- Thurs when I work and then 16-17 hr fasting is easier when I’m home and more relaxed Fri-Sun. interesting that LG indicated slightly shorter fasts were easier for females because that is definitely how I feel on the days I work.

  91. my dad and i are both natural WHENers. i rarely wake up hungry and when i’m busy my body really doesn’t require fuel in the way of food…i forget to eat some days when i’m busy at work. is this my body’s way of keeping me in an alert, fasted state when i need it? maybe.

  92. i have noticed that my kids are never hungry when they are outside playing with their friends, but when they are stuck in the house all i hear is i’m hungry, i’m thirsty…. definitely think exercise and keeping busy helps to suppress the appetite, with child obesity at an all time high i think kids really do need to get out more, stay active and busy and eat less, hunger is not always a bad thing

  93. I just started experimenting with fasting recently, replacing breakfast with coffee and a little coconut milk.

    Today I completed my first 22 hour fast eating a huge primal dinner at around 6pm. Nothing but coffee/CC for breakfast and lunch. I felt completely fine with few real hunger pangs and found the major hurdle was the mental effort required to ignore my ingrained meal times.

    As I want to repeat the fast tomorrow I ate a huge amaount even though I wasnt really hungry, probably the equivalent of 2.5 meals.

    I’m wondering if you IFers out there usually eat a huge refeed meal or a regular sized one.

    1. I eat a regular sized meal after a fast – mostly because I want to avoid the impulse to binge eat, which is not necessarily an issue for everyone. I’ve noticed that I’m likely to have a snack sometime the next day that I wouldn’t ordinarily eat, but it’s still not entirely replacing the missing meals. I’ve heard other people say they have huge meals after a fast, so apparently there’s a lot of variation.

      Also, I’ve found it MUCH easier to skip dinner than breakfast, so I begin fasts after lunch rather than after dinner. Just goes to show that everyone is different and you have to find your own way.

  94. Though I’ve been travelling for 4 months and basically following WHEN, for over a year I was doing leangains pretty much every day with the occasional longer fast on rest days when it felt right.

    So, 20-24 hours maybe once every 10 days, and 15-16 hours almost every day. I ate breakfast sometimes too, but only if I was super hungry in the morning.

    Also – I didn’t bother with either the BCAA’s preworkout or a low fat day with the carb refeeds on training days, and still got to a low-enough bf% (probably 8%), while deadlifting 365 lbs, squatting 345 lbs, benching 210 lbs, and chinning with 55lbs attached. I weigh(ed) 170 lbs. Just gotta make those meals COUNT. Rest days were fairly low carb (maybe 50-80 g).

    1. I should also make the point that I’m a young-ish guy (27) and I’ve never been overweight or had to dramatically repair my metabolism (once I ditched overtraining, anyway), and I have zero problems smashing 2000+ calories in one sitting if I want to.

  95. Hi, I’m not sure if someone has asked this but I just started IF a few weeks ago. Doing a 14-16 hour fast each day. I got to wondering though if it is okay if trying to get pregnant? Not sure if it might reduce my chances or help.


    1. Fasting either has no impact or a somewhat negative impact on fertility, depending on how it is done. If you are not well nourished with quality food, like your standard primal blueprint diet, then the fasting could cause some hormonal issues for you. But if you are healthy when beginning fasting and not too deep in an overall calorie deficit, you shouldn’t have any issues.

      I, myself, ann doing minimally 16/8 fasts almost every day of the week, with a few longer ones thrown in there, and am TTC our fourth baby. No issues yet that I can tell, but as I am sure you’ve found the literature on fasting for females (especially those not focused on strength gains) is somewhat spotty.

      1. Thanks. I think I am pretty healthy. Just want to make sure I have the best chance possible. And am impatient! Trying for 5 months but I hear that is not long complared to some.

        1. The waiting can be SO hard! You may consider slightly increasing your carbs as that promotes fertility, too, but mostly it is a matter of hormones and timing.

          Good luck to you!

  96. I so prefer eating WHEN. Before I got bit by a deer tick (and ended up on food-dependent medication) and was about 3 weeks into the PB, I started to skip breakfast and, for the first time in my life, did not suffer ill-effects of missing “the most important meal of the day.”

    Not only am I looking forward to the end of this antibiotics cycle, and getting it OUT of my otherwise clean system, I am looking forward to being able to eat WHEN again, and not because the pills will rip apart my stomach.

    Thanks for the article, and reinforcing the idea of eating when HUNGRY.

    1. I have had “the most important meal of the day” about 40 times in the last 30 years.

      Trust me on this one? It ain’t.

      On top of that, I violate the CW and eat a really big meal just before hitting the sack.

      It has not had terrible repercussions on my health.

      Oh, and it looks a lot like Ori’s plan.


  97. I would love to try the leangains program but my schedule wont allow me to workout in a fasted state. Has anybody tried or have any thoughts on breaking the 16 hour fast into two 8 hour fasts with an 8 hour eating window in between?

  98. I started out following Lean Gains, but it turned into WHEN. 16/8 is my usual schedule, but it will deviate on rest days (often 24 hour fast), weekends (end up hanging out with some friends and eating earlier, so only 12 hours possibly), and work trips (I’m busy so I don’t think about food for an entire day–30+ hours).

    Works for me! I think we should do what is natural and convenient for us.

  99. I practice the Warrior Diet. Best diet if you want to be lean and mean. I highly recommend it!

  100. I like doing 3-day fasts, nothing but water. I always feel amazing afterward!

  101. Dear Mark

    I have read all 5 of your articles on fasting. Thank you for all the great information.

    But it wasn’t until I read this one that I really understood what IF was.

    Holy COW! I have been doing a cross between Ori’s Warrior plan and “eat when hungry” for the past 30 years!

    And you know what? It doesn’t bother me at all!

    So many people look at me like I’ve got a 3rd eye when I tell them what horrible things I do to my stomach (lol). I’ve been told so many times about the importance of eating regularly that I have lost count.

    My reply? I eat when I am hungy. And if I am really hungry, I eat a lot. Nowadays, it is mostly beef and raw vegetables. Trust me, I am well satiated.

    And I am willing to bet that it is “primal” too? I bet our ancestors didn’t eat regularly either…

  102. Hi Mark,

    I am struggling to find an IF method that works for me. I am focussed on losing fat and the leangains method seems to fit naturally with when I get hungry (afternoon) and when I seem to handle having little/no food (morning). However, how can this fit in with a usual working schedule? If I cannot work out until around 7:30pm after work, should I shift the entire fasting period?
    Also, I can’t find anywhere how many IF days versus rest days you are supposed to have in a typical week.


  103. I’ve been eating 90%-95% primal since January of this year, after working my way into it over the preceding three months. Then in March started IFing for 8 hrs, then 16, and now I’m up to 24 hrs twice a week, which is basically Eat-Stop-Eat. It’s been great. I’ve gone from 183lbs Sept. 1st, 2011 to 166 lbs as of this morning.BF% from 23 to 14.

    I feel fantastic! Have more than enough energy to work, exercise, and enjoy myself. I’m sleeping better, no more acid reflux, and as mkessler17 wrote, I’m much calmer and less prone to getting stressed at my job. Add in to that the very simple, yet effective Primal Blueprint Fitness plan and I’m stronger, faster, and fitter then I’ve been in 20 years. Can’t complain about that at all!

  104. I’ve been doing the leangains/warrior diet approach for 2 years while working in construction & doing all sorts of physical work for 11 hours a day. Wouldn’t have it any other way now when it comes to eating.. and if I feel hungry.. I eat. If I wasn’t doing so much physical work, I would definitely be fasting for longer & eating & lifting bigger!

  105. I used to do Alternate Day fasting about 30 years ago. I was young and wanted to lose fat so I just decided not to eat on Monday, Wed & Fri. It was difficult at first but I quickly acclimated to it, and even went 3 days once, just for yuks. It was very effective for fat loss.

    What helped me is that whatever I craved on a fast day I promised myself that I would have the very next day. I soon found that I couldn’t eat everything that I craved the previous day, hahahaa, but I made sure to treat myself to whatever I wanted on eating days and it worked for me.

    Best wishes to everyone who tries fasting!

  106. I took a long break from reading LC/Paleo blogs, and it was quite a treat to come back and find this series on fasting. Thank you, Mark!

    My fasting schedule has evolved into 16/8 five days a week, a “cheat day” on Thursday when I can eat anything I want with no restrictions, and a 40-hour fast from Friday midnight to Saturday at 4 PM.

    I’ve never been a breakfast eater. I drink black coffee in the mornings, then water throughout the day until I finally feel real hunger (usually not until after 6 PM). My evening meal isn’t exactly the Warrior Diet “feast”–it’s what has always been a normal-sized dinner for me, and that’s usually more than adequate. Occasionally I might eat a small snack later, just before the window closes at midnight, but usually I don’t.

    My Thursday “cheat days” happen to be my busiest day of the week, when I have the least free time during the day to eat. I can eat whatever I like from the moment I get out of bed until midnight, but I have to squeeze it in around a very busy schedule (and I won’t eat in the car or at my desk, which narrows it further). So even though I might eat things such as pizza, cake, ice cream, candy, or bread, I still end up eating far less food on Thursdays than I used to eat in my SAD days.

    If I wanted to binge on junk food on Thursday evenings, I could (and I’ve given myself free rein to do just that) but usually I’m tired and already feeling sort of yucky from whatever wheat/sugar junk I ate earlier in the day, so I almost never actually do it. I usually make a veggie omelet or put leftover meat on a small salad because it’s the easiest option, and that’s dinner.

    On Fridays, I wake up feeling the effects of whatever crapfood I ate the day before, and I’m more than happy to fast. It’s a relief, and however yucky I feel upon waking I feel eager and even grateful for the fast. By mid-afternoon, any residual cruddy feeling from Thursday’s indulgences is long gone, and it’s smooth sailing. I sometimes extend the fast into Sunday if genuine hunger hasn’t yet kicked back in. And then I go right back into my usual 16/8 schedule.

    Eventually, I won’t need the cheat day. As time goes by, I let more Thursdays pass with only one small indulgence, or without eating any junk at all. But it’s been useful as a way of dealing with cravings–if I crave something on Monday, I know I can have it on Thursday, so I anticipate eating it then. I think about how great it will be to have it. And then Thursday rolls around and more often than not I don’t want it after all!

    Psychologically, giving myself a “yes, but later” option works far better than “no.” Like a lot of women, I’ve been in a lifelong battle with food, seeing my own body as an adversary, and this IF/indulge/fast schedule has really helped me get over a lot of negative ideas about my body. I don’t feel like I’m locked in a hopeless battle against myself, food, and fat anymore, and it’s a tremendous relief.

    Physically, fasting has finally started to shift some very stubborn belly fat that just would. not. go. After I lost most of my soft “flub,” I still had a firm, dense mound of abdominal fat that seemed determined to stay, no matter what. And now, slowly but surely, it’s going. I still look 5-6 months pregnant, but the belly is definitely smaller than it was. Also, I am no longer stiff in the mornings, my knees don’t hurt at all anymore, and at 45 my skin looks far better than it did a decade ago. I also haven’t had any allergy symptoms so far this spring, which just amazes me–not having to pop antihistamines, or buy extra boxes of Kleenex? Awesome.

  107. Fasting with bone broth seems a sensible choice for some of us. I’m already thin so like some of you didn’t want to lose too much weight. I recently did a 72 hr. fast and benefited from it. The last 24 hrs or so I also ate some of the gelatin and fat from the bones I made the broth from and that felt very nourishing and helped sustain me. A weekly 24 hr fast seems like a good thing to try.

  108. I’ve been a primal eater for 10 months now. I thought it would be a safe time to start IF’ing now that most SAD symptoms are gone (IBS, acne & mood swings the major ones). I’ve been doing the 14/10 method for 2 weeks, most days. I am pleased with the results and find it easily fits my schedule. However, when I do break my fast, after that first meal (usually around 12 or 1pm), my stomach goes crazy making gas. It’s embarrasing because I am in meetings and/or sitting at a cubical. My meals aren’t larger whilst fasting. Infact I want less food than when I was eating 3 square meals with snacks. The food hasen’t changed – meat, eggs, lettuce, veggies, sometimes tubers. has anyone else experienced the same problem? Any tips to avoid it?

  109. I have successfully lost weight and regained health through Doug Kaufmann’s Phase one diet. I fine tuned this diet through Mark’s primal blueprint. Now, I stick to the primal blueprint while following the Warrior’s diet’s eating schedule. I rarely get hungry now until after 3 or 4 pm and this seems to work for me.Since I have implemented the Warrior’s diet sometime last November, many people have commented on how great I look. I still have a few pounds to go but overall I have lost 105 pounds and counting, over ten inches off my waste and I am no longer troubled by asthma, allergies, apnea, bipolar, congestive heart failure and gal stone’s. Thank You Mark and continue to preach the gospel of healthy living. 😀

  110. I most closely follow the leangains approach by fasting overnight…but I was wondering about eating higher carb/low fat on training days and how necessary it is?

    I am on a GAPs/anti-candida diet which is very high fat and fairly low carb (I eat lots of greens/veggies and carrots, no fruits or sweet potatoes, etc.) but I weight train twice a week trying to add bulk mainly to my glutes. I find it difficult to eat low fat and possibly even counterproductive to the candida cleanse. Can I just do a high carb post-workout, or does it have to be a full day? About how many grams would you consider low fat?

  111. So, I’m on day 2 of IF and day 2 of PB. So far so good. Yesterday I did a 16/8, but I’m thinking that since I’m a women, would it be better that I do a 14/10? Also, I work shift work (7am-7pm or 7pm-7am). The best IF schedule for me would be something like (14/10 split): IF from 11pm to 1pm or(16/8): IF from 11pm to 3pm. Would this be okay??

    1. Also, I’ve noticed I started to breakout. Normal?? I’m assuming it’s my body getting rid of toxins…. Anyone else notice this when stopping CW?


  112. i am thinking of doing the lean gaines approach. my question is monday through thursday i can’t work out because of my schedule so i usually work out friday saturday and sunday. is this still an effective method if i fast from say 11pm til 1pm the next day? thanks for your help!

  113. Hello,

    I’m going to ask a stupid question. How critical are fasted workouts to the success of any intermittent fasting protocols? I am looking particularly at the lean gains protocol, where you do 16/8.

    I work fairly early at 6:30am and no gym opens early enough so I end up working out at 4:30pm instead. Day job is 6:30 to 3:30pm. I was thinking if I could follow 16/8 and just break my fast at noon with a very light lunch (~30%) and then hit the gym at 4:30pm, and have the rest of my daily caloric needs after working out at ~ 7pm.

    Again, I’m just curious if this is even advised as every IF protocol works out fasted (or near fasted with BCAAs).


  114. Aw, this was a very nice post. In thought I want to put in writing like this additionally – taking time and precise effort to make a very good article… but what can I say… I procrastinate alot and by no means seem to get something done.

  115. Quick rundown in hopes for perspectives on what’s NOT working with IF thus far…

    Jan-Oct 2010: gastrointestinal issues prompt eating amendments to no carbs, no soda/juices, only lean meats, veggies. Initially forced to eat only when able, then increasing to two solid meals/day. Breakfast on & off – usually something small like tea & yogurt.

    Oct 2010-April/May 2011: engagement, wedding planning, P90X, walking @ work (after lunch) – look great, feel great! Eating three meals, some light snacking.

    May-Nov 2011: Less working out, light weights, still walking @ work, maintaining clean eating habits, increasing wedding stress…weight loss then fairly immediate gain (tho minimal 1-2 lbs). Eating irregular, typically lunch a sure bet.

    Nov 2011-Dec 2011: Wedding/honeymoon/holidays left little room for exercise time. Little to no walking.

    Jan 2012: Adopted two puppies – walking & playing in yard w/ them. Still walking at work after lunch, tho less frequently.
    Back to lunch & dinner, intermittent b-fast of tea & yogurt.

    Feb 2012-Present:
    Experienced 12 lb. weight gain & feel miserable about self-image.
    Still eating clean throughout week – allowing for “cheats” on weekends.

    About 3 weeks, experimenting w/ IF from 8:30pm-noon with little success per weight loss (just able to get more done at work, lol!).
    Still walking at work after lunch.

    Trying to portion out snacks like nuts & berries to ensure not overeating. Incorporating fruits as snacks (no juices though). Most meals are protein & veggies, sweet taters here & there.

    Attempts at light work outs but often feel COMPLETELY exhausted & drained at end of work day. (We’re up at 5:30am w/ pups, getting ready for day & 35-minute drive to work, get home around 6pm.)

    Dunno if maybe I’m just eating too much (even if “clean”) for lunch & dinner w/ some snacking versus the amount of exercise I’m (NOT) doing?
    Attempts at IF with the idea of cutting out a meal would be beneficial, but no changes thus far.

    Will feel a bit silly if the answer seems apparent to everyone else but me…but that’s how we learn! Open to helpful thoughts.

  116. Sorry, should have noted that it hasn’t all been IF. Some eat-when & some IF.

  117. I just wanted to say THANK YOU for describing your erratic fasting! I started PB a few months ago, however, I keep my carbs very low, even some vegetables rub me the wrong way! When I started skipping meals, I didn’t think it was a big deal, but when I went several days of eating one meal, or going a day and a half without eating, I started getting worried that my lack of hunger was illness! I am very glad to hear that I can truly eat only when I am hungry, and not be wasting my muscles away.

  118. can you get the benefits of IF without doing IF?
    according to John Kiefer, author of the ebook Carb Backloading, you can.
    on his website he has a three part article on IF, which explains how to do it correctly. kiefer’s CBL protocol is definitely a notch up from Berkhan’s Leangains

  119. hi there,

    the only way to do the first fasting option would be like:

    Start fasting – 9.30 PM
    Start eating – 11.30 AM

    Since I have a day job in the office, I am not able to do my sports right at the end after my fasting period. (because I am at the office)

    Would that effect the benefits of my fasting? I want to lose body fat and create a lean muscled (not too much) body.



  120. Hi, I’ve been reading a bunch of your blog posts on the recommendation of a co-worker, and I have two questions on the current topic..
    1) I’ve been eating too many carbs the last few months; how long should I take to get fat adapted before starting IF?
    2) has there been much work toward sorting out which sex-based differences are hormonal or physiological and which are more related to body size and composition (there hasn’t that I’m aware of, but perhaps someone else knows)? As a 5’11” female mesomorph, I sometimes don’t know whether to follow the women’s version or the men’s version of some regimens.


  121. I tried doing two 24 fasts per week with good results but I found the last 4 hours to be tough. Since then, I have switched to three 18 hour fasts, which I find to be more agreeable. Combined with a wheat free diet and three workouts a week, I feel great and am seeing my abs emerge even though I’m 54.

  122. I am a firm believer in Fasting it is the healthiest thing I’ve ever done. I have been on liquid fast for 77 days and 100, but the most negative for me is post fast weight gain has been very depressing for both fast for me gaining more than I lost. Mark what is the best way to maintain the weight loose once you reach your goal, to keep off, I’m very frustrated about it. Thanks for you answer.

    1. Me too. I eventually concluded that I am a carb-addict. I lose track of my caloric intake with breads, pastas, potatoes etc. I am rarely full and crave it more and more. Two years ago I discovered Paleo and that changed things dramatically.
      Unfortunately, addicts who associate with addicts have a much higher chance of sliding back into old bad habits which I have done twice and put on a lot of weight until my knees and ankles are hurting.
      Now I am slowly converting those around me to paleo and it’s making life a lot easier.
      Bottom line: stay away from carbs… Forever.

  123. What if you don’t workout? I have the occasional long walk but hate the gym.i just eat when Im hungry. Weight has plateaued. What to do next?

  124. I like fasting completely with tea and water for 6 days and then eating with liberty on the 7th. I’ve done many 40-day fasts and found them easy physically ( no hunger) but difficult socially (awkward moments when everyone is eating and I am not, having to listen to everyone’s opinion, they’re concern that I am a whacko etc). By eating on Fridays or Saturdays I can host dinner-parties, go out to restaurants etc and it’s stress-free.

  125. I’ll chime in here to say that I started the 16hr fasting approach a week ago after reading this blog. I’m 5’10” and 265lbs. I’ll be very solid at 210. Was 296 as of last March. Always did lots of exercise, from powerlifting to sprint triathlons, so I was a fit fat guy. Still am but thankfully eat primal for 8mos and its very easy for me now.

    I only started thinking about this fasting approach after regaining from my low of 260. Was snacking at night on almond butter and cream. Calories add up!

    The 16hr fast works wonderfully for me. And I find my breaking the fast meals are picture perfect. Always salad and then some steak or seafood if eating out. I do 8pm to noon and it works great for me. I’m finding that I’m very alert and not dying at all. I was binging the first two days bait which concerned me but I monitored it. The subsequent 5 days, I’ve hit a groove and would estimate I’m eating 350-500 cals less each day. I’ve lost a pound and a half since starting.

    I track my weight each day and previously counted cals. I don’t feel I need to count cals with this approach. I just make sure I eat a delish lunch, berries for dessert and no snack then a filling low carb dinner of the same cals as I used to eat. I’m probably taking in 2750cals and my BMR plus daily exercise is close to 3500.

    Will keep you posted. My interim goal weight is 250, and I work out with 500lbs on dead lift, for example, and swim, surf, and walk the golf course and jump rope as my various activities.

  126. Hi, I’ve started the Lean Gains 16 hour fast today and I have some questions that I hope someone could help me answer. My main goal is to lose weight and fat.

    I’m exercising 3X a week (from 7:30 AM to 8:00 AM) and every day I have my first meal at around 09:00 AM. I have lunch around 12:30 PM and a Snack around 4:30 PM

    My daily 16 hour fast is from 5:00 PM to 9:00 AM the next morning every day. I know this isn’t exactly the schedule of Leangains but it’s the one I feel most comfortable with given my work / family schedule.

    Does this schedule look ok for my goal?

    Is it really necessary to consume BCAA’s? Can I substitute BCAA’s with Whey Protein?

    Thank you,


  127. I am playing around with fasting. I can’t manage 24 hours about the best I’ve been able to do is limit my eating to a 10 to 11 hour window and fast for the other 13 to 14 hours. I’ve been doing this all week and I’m down a few pounds and seem to be leaner (though could be my imagination.

    My quesiton, is this cycle of fasting really going to show results? Or do I not bother if I can’t go for 24 hours or get down to an 8 hour window?

  128. How does alcohol fit into the fast? How does it, or does it effect metabolism? Say I’m not eating after 8 pm, only drinking fluids, does alcohol hinder benefits?

    1. It really doesn’t. Not only is it high in calories (which defeats the purpose), it is also burned before fat. Not to mention the toxicity would be that much more powerful in an unfed state with nothing to ameliorate the effects. Just go without. If you can’t go without for such a short period, your local AA might be interested in meeting you.

  129. Aceste etape sunt foarte importante in crearea unui site, sau daca acesta este deja creat trebuie facute in cayul in care doriti un succes garantat pentru afacerea pe care o detineti. Astfel dupa cum va puteti da seama acest mod de a promova produsele si serviciile este foarte la moda si totodata foarte eficient, si rezultatele vor fi vizibile si durabile in timp.

  130. is there too long to fast? I only eat after work already but I tend to eat too much. if my last meal on Sunday night is at 6pm, fast all day the next day, eat the next day only after work it would make it about a 46 hr fast with a 2 hour eating window. do the fast Monday Wednesday and Friday. would that be too much?

  131. i heard an interview of a brain cancer MD (forget his name) on Jimmy Moore.

    he advocates like 5 days fast once year for brain health.
    (his fast is minimal calorie like 10% of normal calories since NO food for so long is very hard)

    i usually do 16 hr/day.


  132. Hey Mark!

    Quick thought / question.

    I like the idea of intermittent fasting and have just given it a try this week. I’m trying to follow the leangains guide and I’m feeling pretty good, no hunger issues. My main concern is trying to get enough protein in during that 8 hour period. I know you’ve discussed getting around .7/lb of lean mass, which puts me around 185 grams / daily. In your opinion if I eat 100 grams of protein, will my body actually be able to use it all? I’ve been led to believe that I can only absorb and utilize around 40-50 grams per meal / every couple hours.. If that is indeed the case, daily intermittent fasting will keep me from getting ample amounts of protein in. What are your thoughts? Thank you for your time. – dave

  133. Your programme is absolutely brilliant! I do not really need to loose weight but I feel so good doing the 16 hour fast. I don’t like exercise (i am just too lazy). I have been doing it for months now and it has become second nature. Small breakfast, regular 3 course lunch and small snack at 4 o’clock teatime. I am NEVER hungry! Bless you – and I am living proof that it does work!!!

  134. I’ve been playing with this a bit lately and actually enjoy the freedom it gives me to eat when I want and not eat breakfast just because I should. Two meals a day with a possible snack in the middle is working for me as far as how I feel. I do have one question though: I usually put collagen in my coffee or tea in the morning which does have protein in it. Is that considered breaking the fast? I use it mostly as a supplement but I also think it might help keep hunger at bay, although I’m not positive on that and it’s not why I add it.
    Thanks for any thoughts on this.

  135. im a type two diabetic not on insulin. I’ve been 16:8 or 18:6 for quite a while. I’ve recently worked up to doing a consecutive 72 hour fast once a week. I’ve been struggling ringer in enough calories eating 16:8 on my feasting day. I think I’m going tonseitch to 14:10 on my feast days. I also am trying to eat earlier in the day because my blood sugar is lower. I’m doing this not just for weight loss bit to lower my insulin and blood sugars.

  136. Hi, love your website. I am trying an alternating fast 2 days fast, 3 days eat “normally” and then again 2 days fast. It is surprisingly easy to fast. On fast days I eat maybe 2 hard boiled eggs and an apple. If I have a serious craving then I eat another apple. I also have coffee, black with skim milk and of course water.

    About 7 years ago I quit smoking and had a lot of ups and downs with my weight. If you have the will-power to stop tobacco then you have the will-power to fast.

  137. Thanks so much for these great articles Marc!
    I’m actually at true North health clinic in Santa Rosa doing a two week water fast right now. I thought I would read up on the tremendous benefits of fasting and your articles nailed it.
    Just google true North in Santa Rosa fasting and he will come up. Keep up the great work!