Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
15 Mar

Why Fast? Part One – Weight Loss

plate“When a person has nothing to eat, fasting is the smartest thing he could do.” – Herman Hesse, Siddhartha.

I like that quote. It’s making (non-caloric) lemonade out of lemons, and for all the transcendental insights contained in Hesse’s book, this line strikes me as a really cool, no-nonsense way to make the best out of a bad situation. No doubt about that. But how useful is it, really, to today’s readers? Very few of us ever have “nothing to eat.” On the contrary, food is ever at our beck and call, with very little effort required to obtain it. Actually, that’s not completely true. Processed junk and fast food is readily available, while the good stuff – fresh meat and veggies, actual, you know, food - requires prep work, cooking, time, and the doing of dishes. But the main point stands: we rarely go without.

That doesn’t mean the quote is useless. In fact, with a few slight modifications, it becomes extremely effective weight loss advice. Check out my version:

“When a person has had too much to eat, fasting is the smartest thing he could do.” – Mark Sisson, Mark’s Daily Apple.

If that sounds harsh or even unrealistic, consider the story of the Scotsman. Back in 1965, an obese Scotsman of 27 years and 456 pounds came to the Department of Medicine in Dundee, Scotland, with a problem. He needed to lose weight. A (1/8 of a) ton of it. The doctors suggested maybe not eating for a few days could help. It was just an offhand recommendation, but our Scotsman (known only as “AB”) really took to it. He stayed at the hospital for several days, taking only water and vitamin pills while undergoing observation to ensure nothing went wrong. When his time was up, he continued the fast back at home, returning to the hospital only for regular monitoring. After a week, he was down five pounds and feeling good. His vitals checked out, blood pressure was normal, and though he had lower blood sugar than most men, he didn’t seem particularly impaired by it. The experiment continued… for 382 days.

Yes, AB fasted for 382 days, drinking only water and taking vitamin, potassium, and sodium supplements. All told, he lost 276 pounds, reaching his target weight of 180 pounds and maintaining the bulk of his weight loss. Over the five following years of observation, AB regained just sixteen pounds, putting him in excellent, but underpopulated territory (at least 80% of dieters eventually regain all the lost weight). Other doctors paid attention. Maybe it was the fact that it was the 60s, and all sorts of crazy stuff was going on – rebellion in the air, good music being made, a war in Vietnam, Ken Kesey and his Merry Pranksters blazing across the U.S. in a beat-up school bus, spreading the good weird word, Kevin Arnold and a young Marilyn Manson coming of age in Anytown, USA – but for whatever reason, placing obese patients on extended and short-term fasts became relatively common practice.

But could this work for the average person looking to lose weight without submitting to constant medical observation?

Absolutely. Study after study shows that whatever you want to call the protocol – intermittent fasting, fasting, alternate day fasting, or alternate day caloric restriction – it works very well for weight loss. A few recent ones:

So, yes: it works. But does fasting work solely through caloric restriction, or is it doing something special?

That’s the real question. There’s no question that fasting causes weight loss through caloric restriction. Obviously, when you don’t eat anything, your body turns to its own stored energy reserves, reserves that take up physical space and have mass. Depletion of those energy stores reduces mass and thus weight. Total and absolute caloric restriction. That’s elementary stuff and the studies from the 1960s show that.

To dig a bit deeper, let’s look at how weight loss occurs during a fast. I’ll stick to research involving humans only (sorry, rodent personal trainers).

Secretion of growth hormone, one of the premier fat burning hormones, increases during a fast. In a five-day fasting protocol, men experienced increased GH secretion on day one and day five (the only two days where GH was measured). A later study showed that during two-day fasting sessions, growth hormone secretions increased in both frequency and intensity in men. They experienced more frequent GH bursts and each burst secreted a higher mass of GH. A more recent study found that 24-hour fasts increased GH by 1300% in women and almost 2000% in men.

Fasting decreases fasting insulin levels. The presence of insulin inhibits lipolysis, the release of stored triglycerides (body fat). Without lipolysis actually releasing stored body fat, it’s rather difficult to, well, burn that body fat for energy. During a fast, fasting insulin decreases and lipolysis increases. This insulin-blunting aspect of fasting quite literally allows the fast to be successful, because without the ability to access stored body fat for energy, making it through a period of zero caloric intake will be nigh impossible.

Fasting improves insulin sensitivity. 20-hour fasts were enough to improve insulin sensitivity in men.

Fasting increases the catecholamines, both adrenaline (epinephrine) and noradrenaline (norepinephrine). Both catecholamines increase resting energy expenditure during a fast, and guess where your fasting body finds the energy to expend? From body fat. Catecholamines activate hormone sensitive lipase present in adipose tissue, spurring the release of said fat. This makes intuitive sense, doesn’t it? If you’re hungry in the wild, you need to hunt (or gather, or fish, or somehow procure food) and you need energy to do it. The catecholamines help provide some of that energy while burning fat in the process.

Hmm, notice anything? All those mechanisms dealt with fat burning specifically. While there may be some weirdo out there who’s interested in reducing bone mineral density and muscle mass while maintaining fat tissue, I would wager that what most people mean by “weight loss” is “fat mass loss.” From the stuff I just linked, it looks like fasting burns fat, rather than just weight. But what about Conventional Wisdom which claims that fasting increases muscle wasting – maybe because your body will totally recognize the lethal nature of all that arterycloggingsaturated animal fat and choose to break down muscle instead? Is it true?

Let’s go to the research:

In one study, normal weight subjects ate just once a day without reducing overall caloric intake. Weight didn’t change, which isn’t really surprising, but body composition did change – and for the better. Body fat decreased and lean weight increased (in addition to a bunch of other beneficial changes) without an overall reduction in calories.

recent review of the relevant literature found that while fasting and caloric restriction are “equally as effective in decreasing body weight and fat mass,” fasting is “more effective for the retention of lean mass.”

Conventional Wisdom strikes out again.

In closing…

It appears that fasting “works” in several different ways:

1. It decreases caloric intake. In order to lose weight, you need a caloric deficit. That really isn’t in contention here, folks.

2. It increases fat oxidation while sparing lean mass. Since what we’re trying to do is lose fat (rather than just “weight”), the fact that fasting increases hormones that preferentially burn fat and decreases hormones that inhibit fat burning is extremely desirable.

3. It improves adherence. In most of the studies surveyed, participants found fasting to be an extremely tolerable way to diet, especially when compared to outright caloric restriction. Even AB, the fasting Scotsman, reported very little difficulty throughout his 382 day fast. If fasting is easier for you than trying to laboriously count calories, fasting is going to be the more effective weight – er, fat – loss method.

All in all, fasting is an effective way to lose body fat. It’s not the only way, and it isn’t “required” for Primal weight loss, but many in the community have found it to be very helpful and the literature backs them up. If you’re looking to jumpstart your fat loss, fasting may be just the ticket. To get some ideas, be sure to check out my post on various fasting methods.

In subsequent installments, I’ll highlight some of the other benefits of fasting. There are a ton, and new research is being released all the time, so I expect I’ll have a lot to discuss. Until then, I’d like to hear about your experiences with fasting for fat loss. Has it worked? Has it failed you? Let us know in the comment section!

Thanks for reading, everyone!

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

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. Um, to everyone pointing out the Marilyn Manson wasn’t really on the Wonder Years, you do realize Mark was joking right? I also feel compelled to point out that Kevin Arnold didn’t REALLY live in the 60’s either, seeing as he’s a CHARACTER. How did you let THAT get past you?

    John wrote on March 15th, 2012
  2. I have one meal a day, most days. It’s making a huge difference in strength gains, fat loss and mood stability. I also love not having to pack anything for lunch.

    knifegill wrote on March 15th, 2012
  3. I’ve always heard if you fast you put your body in starvation mode-so when you do eat it hoards those calories and converts them into fat (to store for the next potential fast). Is that true? What happens to the body after breaking the fast?

    Kay wrote on March 15th, 2012
    • I’ve also head this as well. I think Mark has covered this before, but I can’t find the article. I’m also very interested in what happens to the calories you consume after a fast.

      Cecilia wrote on March 16th, 2012
  4. It works! been applying intermitent fasting (one two hour window) 5 or six days per week for the last year. I am down 110 lbs and have more muscle then ever! I’m hardly ever hungry too! Nice post mark can’t wait to read part 2!

    Brian wrote on March 15th, 2012
  5. People who want to lose weight commonly, and first of all, think about reducing the amount of food they eat. This may be quite a solution but not exactly the best there is. In fact, depending on the amount you reduce in your food intake, it may even be dangerous to one’s health. So how does one lose weight effectively and safely? Here are some points one should consider when trying to lose weight:

    http://www.tutstuff.com/pointers-on-losing-weight-safely/

    Nash wrote on March 15th, 2012
  6. Anyone reading this post do bulletproof coffee? I’ve started drinking coffee with unsalted butter, coconut oil, and cinnamon in the mornings as Dave Asprey (bulletproof exec) claims it will not ‘break’ your fast. Seems some others on here who have posted would disagree?

    Dan wrote on March 15th, 2012
    • I intend to try Bulletproof soon! It sounds great! I’ve already blended grass-fed butter into my coffee and it’s way thicker and richer than milk. Mmm!

      Erika wrote on March 15th, 2012
    • Yes! That butter coffee thing is the BEST nutritional tip I’ve ever found. On two 16 ounce mugs of butter coffee per day I can eat every 2 or 3 days whether I need to or not. NO fatigue or cravings for food of any kind because butter IS food, just a pure, concentrated fat type of macro nutrient.

      For each 16 ounce travel mug of coffee I add 2 tablespoon of unsalted butter at 100 calories per and 1 tablespoon of coconut oil at 110 calories per, so my total fat intake for 2 – 16 ounce travel mugs of coffee is around 620 calories, WAY below the 1800, 2200 or 2500 calorie intake that is taken for and preached as nutritional gospel by the FDA, mainstream medicine, carb addicted dieticians & nutritionists, etc.

      On the butter coffee I’m learning how to eat to live rather than the other way around, and with my current (temporary) mostly sedentary lifestyle I just don’t need much food anyway. I do make sure to take a full set of chelated multi vitamins and chelated multi minerals and my 2.6 grams Omega-6 evening primrose or organic FLORA brand sunflower oil balanced with 1.3 grams of Omega-3 flax for cellular nutrition, but otherwise no other food.

      What this type of butter fast amounts to is MACRO NUTRIENT restriction rather than calorie restriction, and that’s why I seem to be able to go long periods without any other foods. I’m still getting some calories but still FAR less than normal or average American intake levels.

      Remember that fats at 9 calories per gram have twice the caloric density than carbs and proteins, but produce around 6 TIMES more ATP energy at the cell level. A 6 carbon glucose molecule (from carbs) produces around 36 or 38 molecules of ATP, but due to metabolic inefficiencies there’s a loss to around 30 ATP’s per, whereas an 18 carbon fatty acid produces 147 units of ATP. LOTS of energy in fats, and it’s one more reason and proof that at a certain point calories don’t matter.

      I realized the best way to keep my body in fat burning mode is to never fall out of it by eating carbs that stop fat burning, Mark’s Carbohydrates Curve chart shows how many grams of carbs you can eat and still stay in a ketotic fat burning state. Just 4 or 5 ounces of carbs (100 grams) is all it takes to stop fat burning, so if you stay under that your body keeps burning fats, including the ones you eat, for energy.

      As a side note went to Denver last week & for some reason was hungry despite the 2 butter coffees, don’t know if it was the altitude or just a different attitude from the change of routine, but I ate twice a day for that week, including more carbs than usual. Felt like I was blowing up but when I checked my weight after I got home I was still at 205 where I was before I went, so no harm no foul, amazing.

      Your mileage may vary, but I HIGHLY recommend it, even if just to learn that your body can run on fats pretty much exclusively and it won’t kill you. Nice to know I can not only survive but flourish even in lean times with macro nutrient mastery.

      cancerclasses wrote on March 15th, 2012
      • Here’s a reference for that ATP info from UCLA:
        http://goo.gl/sxH3d

        cancerclasses wrote on March 15th, 2012
      • That butter coffee sounds great! I have the grass fed butter already and will pick up some good coconut oil today.

        John wrote on March 20th, 2012
    • It won’t break your fast depending on what you are fasting for. If you are fasting for the ketogenic affects of fasting then fats added to your morning coffee or tea supports, not detracts from this. I think MCT oil is a better choice for producing ketones than coconut oil. You will notice a big difference if you use MCT oil.

      Mary Titus wrote on March 17th, 2012
  7. Please, please, please be careful before doing this. I generally wouldn’t recommend it if you’re young, especially young and active, easily stressed; and unless you’re overweight, I wouldn’t recommend it at all. I know this is the point of this post and that Mark has posted cautions about fasting before, but some people might just decide to recklessly jump into it ‘for the benefits’. The way I did.
    I feel better when I eat regularly; have a look at this: http://www.cheeseslave.com/how-intermittent-fasting-caused-my-insomnia-and-belly-fat/. I personally didn’t gain fat, but IF caused a myriad of problems for me – it wrecked my appetite (I am 5’10, very active, and 20 years old, and should have a healthy appetite), I think it’s messed with my thyroid and definitely made me stressed.

    Milla wrote on March 15th, 2012
    • WHat was your diet??? This is very important. Did your diet support fasting? Also, ketosis results in a lack of appettite because your body needs less food. I have been doing intermittent fasting for years and I have a healthy appetite. Not like the insane appetite I had 11 years ago but an appetitie that I can manage without overeating the wrong food. I also fasted many times naturally when I was in college and that scared me. I thought there was something wrong with me because I went 30 hours without eating…It is normal to go 20 hours without eating because our bodies are already built to go a long time wihtou food. We screw that up by eat 4-6 meals a day with snacks. THis not only contributes to obesity but also insulin/glucose instability.

      Mary Titus wrote on March 17th, 2012
  8. What actually counts as “fasting”? Can I drink green/herbal tea? Take multivitamins? Black tea with a bit of milk? Clean my teeth with toothpaste!?
    I’ve always though eating under, say, 50 calories in a day is as good as fasting (assuming those calories come from those similar to above, not food).

    James wrote on March 15th, 2012
    • I think that your 50 calorie rule is pretty close. I drink coffee (no cream or milk), tea, and lemon water during fasts, and had great results. I’ve heard of people using a bit of milk or cream in their coffee and still seeing good results. I would take a magnesium malate supplement as well, but I take any other vitamins with meals. During Ramadan, Muslims fast during the day and don’t take in ANY liquids. If you’re mainly fasting for health, and not religous or other reasons, water and tiny caloric intake is fine.

      John wrote on March 15th, 2012
  9. This may be a silly question, but is it a sign that I should avoid fasting if my stomach is growling?

    I’ve only been going Primal for just over a month now, so maybe my body hasn’t adjusted enough yet?

    I also have experienced days where it was easy or unintentional to skip a meal, and felt fine if not great! But today is not one of those days.

    Erika wrote on March 15th, 2012
    • Not silly at all. I’ve noticed hunger and some stomach growls during a fasting and continued to do it. It really is about intensity. If it’s just mild hunger, you can fast right through it. But if it’s GNAWING at you, you should break your fast. I think benefit of fasting is getting more in tune with your body. Break your fast early, but certainly try again if you want to. Also, you can start by skipping a meal, then two meals, then 12 hours, then 18 hours over a few weeks.

      John wrote on March 15th, 2012
    • Another thing I and some friends have noticed… fasting is much harder after a “cheat” day. Try eating 100% primal for a day or two before starting a fast, and it may be a lot easier.

      John wrote on March 15th, 2012
  10. My great grandfather who I met as a child fasted one day a week for religious reasons. He did not like bread or sweets of any kind. He was a dairy farmer and ate mostly raw whole fat milk, animal fat, meat and very little vegetables because he didn’t like them either. He died at the age of 106 years. In addition his brother in law followed the same diet and fathered a child at the age of 80. these are true stories from my family history. Now the family lives in the big city. Lots of stress, carbs and plenty of food. His great grandchildren all suffers from degenerative diseases. His great great grandchildren all are on meds for hyper active behavior, depression and bad behavior. This makes me think of Dr. Pottenger’s experiment with cats. I am the only family member interested in nutrition and paleo nutrition. I am also the only family member without illness or medication and I am going toward 80. I fast 2 days a week from sundown to sundown. I also trade options and equities to support myself and have money to donate to charity.

    Edward wrote on March 15th, 2012
    • This is outstanding and motivating!

      jbourneidentity wrote on May 4th, 2013
  11. Does anyone know if there are any repercussions with fasting during pregnancy?

    Brian wrote on March 15th, 2012
    • Just from the common sense perspective, the fetus should be fine but your body tissues have a good chance to be used tor the needs of pregnancy. I wouldn’t do it.

      Galina L. wrote on March 15th, 2012
      • I definately would recommend against it. Just think about Grockette. She probably nested, not hunting for long times with the guys (gathering fruits, probably). She probably get the better food too (at least I think Grock would save her the last porkchop, right? Or the fattier pieces).
        Also, the natural way of the female body during pregnancy is to get fatter. There’s no way around it, you’ll need the calories for nursing. The anatomic changes forces you to remain less active too. Women tend to nest. Men tend to protect their pregnant wifes.

        Ever seen pregnants lions in the discovery channel??

        Also, the fetus is a wonder of life and all, but behave like a freaking parasite, doesn’t it? Eating all the calcium in your bones and teeth and all. So I agree with Galina, everything the fetus need will come out from your body. Fat, sure; but also protein, minerals, your sanity…
        Pregnancy is NOT the time to lean out, period. Your biology makes you get fatter, because you need to get fatter. Like the analogy with polar bears hibernating that Taubes uses in his books.

        Reinado wrote on March 15th, 2012
    • Most recommend against it, and I tend to agree. If you miss a meal because you’re not hungry, I think that’s fine, but don’t try and fast through hunger during pregnancy.

      John wrote on March 15th, 2012
  12. The last few times I have tried to lose fat I have struggled, no matter how much exercise I got and how much I limited my carbs. I couldn’t understand why I had been so successful with low carb in the past (but fell off the wagon…never again!) and couldn’t have the same success this time around. What I realized, after finding this page and going 99% primal, is that I used to intermittently fast without thinking about it, and I had stopped doing that when my work hours became predictable and money wasn’t tight any more. I started IF about 2 weeks ago and the results have been nothing short of amazing! The best part is that everyone I talk to about it has been intrigued and supportive rather than conventionally wise…I guess I just run with a good crowd.

    Ed wrote on March 15th, 2012
  13. As if those ancestors of ours had a table full of food every day..man was lean and mighty because he DID NOT eat every meal, every day…and many times it was a longer period of time. many Animals who live through Winter climates are forced to fast or eat very little. THEY are tough. So be a GROK..Don’t eat all the time..ITS OK TO BE HUNGRY. Remember your stomach is only fist size. GO STARVE a bit..it wont hurt..it actually kicks some body fat consumption into gear…ITS COMMON SENSE>..GROK ON>>>

    Dave PAPA GROK Parsons wrote on March 15th, 2012
    • No, Grok definitely didn’t adhere to three-meals-a-day! It’s conventional brainwashing. Go Papa Grok!

      Hillside Gina wrote on March 15th, 2012
  14. Edward, I found your posting quite interesting. I, too, am near 80, have all my own teeth, have never had surgery, and have see a doctor once a year. I find old age quite enjoyable and hope you do, also. Best wishes, Anna

    Anna wrote on March 15th, 2012
  15. Really, there’s a lot to be said for proof reading. I think I meant to say “have seen a doctor once a year”. So all you young guys out there, cheer up, it’s all good.

    Anna wrote on March 15th, 2012
  16. Is it okay to practice IF while trying to conceive?

    shilpa wrote on March 15th, 2012
    • I’m not going to pretend to know any science about it, but that seems awful risky. You would certainly have to avoid the refined processed food (as you are probably already doing)and make sure you get enough direct sunlight (for proper D levels)so that you wouldn’t fall behind on the hormones that are so important for proper fetal development. If my wife wanted to IF during pregnancy, I would ask her to be satisfied with only eating proper food and let her body be what size it needs.
      What are you trying to do with your baby? Avoiding gestational diabetes is important, but if you and the baby are exhibiting satisfactory health already, you should have a healthy baby ceteris peribus. IFing won’t make a healthy baby into a child prodigy, so avoid the risk and be satisfied.

      Joshua wrote on March 22nd, 2012
  17. Is it weird that reading this excellent post on the benefits of fasting has made me hungry??

    Ashley North wrote on March 15th, 2012
  18. I’m wondering about the impact of IF for those of us with compromised thyroids. I’ve read that calorie restriction can cause it to slow down even more. In my own experience, it does seem that my temp runs colder on days when I practice IF (purposefully or accidentally).

    I go through phases where I still practice it…mostly because the mental clarity IF provides is astounding! And think of all the extra time you have in a day when you’re not prepping and eating so often.

    As for the guy who lost all the weight — there’s gotta be some kind of “setpoint” where the body stops dropping, right? Back in my college days, I was anorexic (ate one meal per week). I never LOOKED it because my body just didn’t drop the weight. I imagine that if he’d kept starving himself, he would eventually stop losing weight.

    SmilingJudy wrote on March 15th, 2012
  19. This made me laugh. At myself. After 17 hours of not eating I get very painful stomach cramps

    William wrote on March 15th, 2012
  20. I’m excited to be reading about fasting. I run a small bushcraft/survival school in Maine, and fasting is part of our wilderness survival curriculum. Some of the research I read years ago left me with the understanding that fasting will extend the life of a survivor over eating minimally (ie. not meeting replacement caloric requirements). It’s a common myth that food is a priority in a short-term situation. I’m excited to be reading about it here.

    On a personal note, I fasted one day per week for a year, and have completed eight 7-day water fasts and one 11-day water fast. More intermittent these days.

    Tim Smith wrote on March 15th, 2012
  21. Fasting is definitely a superior way to lose fat.
    It’s also VERY easy to incorporate into an active lifestyle when done ‘right’.
    Nice post Mark.

    Clint wrote on March 15th, 2012
  22. Very inspiring stuff. I’m keen to try to help shift my baby weight. Commonsense (or maybe CW) makes me think I should wait to try IF till I finish breastfeeding?? My baby is only 10 weeks old and I’ll definately breastfeed him for at least 13months as I did my other 2 sons. Does anyone have experience with IF and milk supply? An aside: My supply is currently excellent due to primal fare! (With previous 2 babies I had very low supply on CW diet…was hard work!)

    Berry wrote on March 15th, 2012
    • CW say you could breastfeed until the baby is 6 months old and then quit. I’ll say… listen to your body! Watch bitches!!!

      Yes, I said bitches!! Female dogs naturally get to a point when they start biting their sons when they trying to breastfeed, because… well, I think they’re done with it. Do you feel you’re done with it? Probably not, since your baby is 10 months old! But the moment after the 6 months period (just to be sure) that you feel like “I’m done with this!” is probably the best moment to start to feed the baby the wonderful world of paleo foods. Just listen to your body (and hormones),you’ll know when the time is right!

      Reinado wrote on March 15th, 2012
      • Breastfeeding vs. food isn’t an all-or-nothing practice! The primal way to introduce foods would begin somewhere around the 6-9 month window, but food isn’t going to be a major source of nutrition until that baby is more than a year old. Human milk is more calorically dense and loaded with bioavailable nutrients than anything else.

        More moms see their fat stores mobilized after several months of breastfeeding than right away — give your body time to do what it knows how to do!

        bees on fire wrote on March 17th, 2012
        • Thanks for comments. I definately intend to introduce Primal fare around 6 months. Baby is only 10 weeks at the moment , not 10 months. Lets hope the baby fat will melt away by then :-)

          Berry wrote on March 18th, 2012
  23. Never tried this but very intrigued by the science behind it. Obviously not the best option for me at the moment since I’m not looking to lose weight. But still a very interesting read!

    Sarah @ The Healthy Diva wrote on March 15th, 2012
  24. My partner and I are debating the current health implications of IF when the soils that grow what we need to eat is deplete of nutrients. Is IF then, more harmful and would eating three squares daily and consistently but less volume, better for health?

    Please comment…thanks

    B-) wrote on March 15th, 2012
  25. I’m intrigued by the idea of fasting, but in my experience (some very unhealthy attempts to lose weight in high school) sometimes after not eating enough, I would actually faint. I have low blood pressure so I’m prone to fainting often (about 5-6 times a year!) and usually I like to keep almonds in my bag and never really skip meals. So would IF be possible for someone like me?

    Inessa wrote on March 15th, 2012
  26. I’ve been doing PB for just the past 2 weeks now. Lost 6 lbs and can feel my muscles start to build up. I’ve actually done IF (accidentally) twice now. Fasted for 19 hours one day, 16 hours another before having a really good primal meal! I had no hunger pangs, just kept drinking water, coffee, black tea. Amazing. I’m hypoglycemic also, so I wasn’t sure how well I’d do, but I feel great!

    Lise wrote on March 15th, 2012
  27. I love your timing, Mark! Just embarking on a 3 day fast/retreat starting NOW.

    I got very lean last year doing intermittent fasting (18/6) and it is SO much easier than counting calories.

    Sondra Rose wrote on March 15th, 2012
  28. I run 8/16 right now, but break it with a pretty small lunch; 3 cups chopped vegetables with some olive oil/balsamic (1:1).

    Have been meaning to try extending from 16 to 24. Only have to postpone the vegetables.

    Hunger really hasn’t been an issue. Interested to see how I respond to fasted resistance training.

    Jim B wrote on March 15th, 2012
    • weight training while fasting enhances the production of growth hormone. Don’t ruin that with carbohydrates and don’t eat for an hour following weight training. You will produce healthier muscles and you will be able to maintain that muscle easily.

      Mary Titus wrote on March 15th, 2012
  29. Great timing on this article for me. I’m having the hardest time getting rid of that last bit of belly fat. I think I’m going to use this as inspiration to do a fast. Thanks Mark!

    Clint W wrote on March 15th, 2012
  30. I started playing around with Fasting aka The Warrior Diet at the same time I dove head first into Paleo- both made tough. I never worry about a missed meal and eat pretty damn good when I do

    pjnoir wrote on March 15th, 2012
  31. A healthy fast hurts no one. You can’t fast properly without a good healthy meal. A person with anorexia has no business trying to fast because they will do it incorrectly. A person who has a healthy psyche and understands how the body works can indeed fast and improve their health. Back in the day people did not have a corner grocery store, Mickie Dees, freezer or microwave. They ate in a manner that provided the nourishment needed to get them through several “foodless” days. They were not interested in making a fashion statement. They were interested in survival. Survival is a healthy stated to be in. It makes you understand what you need to eat, YET, in the days of “civilization” we can enjoy this ideal, survival. We can enjoy it more because we don’t have to hunt or gather. Everything is right at our fingertips and all we need is common sense. If you lack common sense then survival is out of reach.

    Mary Titus wrote on March 15th, 2012
  32. I was a little nervous about starting an Intermittent Fast because I thought the hunger would really be a distraction and unbearably uncomfortable. But from what I read, I thought it deserved an honest try. I jumped in to see if I could go a few days. It’s been 2 weeks now and I am really enjoying it. IF is so black and white, so easily defined which is perfect for the way I am. It’s not a lot of rules in between to sort out. I fast 19 hours a day from 8:00 PM til 3:00 PM the next day. During my eating phase I have 2 meals. During the fast, I am more focused and calm, not obsessing over lunch or snacks like I used to. I don’t have brain fog and fatigue during the day. I used to want a 20 minute nap in the afternoon, but not anymore. I am very excited to see where IF takes me as I have about 50 pounds to lose.

    Darren wrote on March 15th, 2012
  33. I’m confused about the benefits of fasting vs. the myth of “eat less, move more.” Low-carb advocates say that our feedback systems will use various mechanisms to conserve energy when we eat less, e.g., increase our appetite, slow down metabolism. Then Mark presents evidence to the contrary. How can both arguments be right?

    jake3_14 wrote on March 15th, 2012
    • “Low-carb advocates say that our feedback systems will use various mechanisms to conserve energy when we eat less”… I’m talking out of my ass here, but I think that would happen ONLY if you don’t have any energy storaged for the fasted times… Like if you open your wallet and see you got like a 100 dollars of fat (in 1 dollar’s bills), would you go into slowing down your money expendage because you got no 10’s???
      The whole idea of “Oh OK, I got lots of fat to burn, so now I’m fasting and I’m going to lose muscle instead” sounds so very wrong. Fat is there to support you when calories are low.

      Reinado wrote on March 15th, 2012
      • Okay, lets say everyone was a hanter-gatherer. You have no concept of medical research or nuthin’ but you do know that you can stand up under bad weather, famine, drought etc, if you kept your protein intake as high as possible. By keeping your fat intake high, you will also keep ketosis high. Ketosis exists to provide energy and maintainence to our cells during famine. Hydration is also maintained even on a reduced intake of fluids because, if there’s famine then no doubt, water will be very scarce. This is why we have no appetite or even feel less thirsty when in ketosis.Fat will be burned because of ketosis…It will be used as energy and whatever else the body needs for it function optimally.

        Mary Titus wrote on March 15th, 2012
  34. I was never much of a dieter, but I was quite overweight. I decided enough was enough so started fasting 16-hours a day, with 8 hour eating windows. I also greatly up’d my Tea drinking and started eating a lot of the healthy super meat, Kangaroo Meat.

    Fast forward 6 months, I’m down almost 50 pounds and have shown no signs of regaining weight.

    Fasting is the dieting of the future.

    Skippy wrote on March 15th, 2012
  35. For all of you who IF, do you still eat the same amount of calories in a day (assuming it’s less than a 24 hour fast)? Do you try to cram a ton of cals into your eating window, or just have normal sized meals?

    Alyssa wrote on March 15th, 2012
    • I try to cram a ton of protein and fats in the eating window(three meals). I listen to my body. I stop if it doesn’t feel right. Eggs are harder to metabolize for me.

      Reinado wrote on March 15th, 2012
  36. I do not restrict my caloric intake but I do not count calories…I make every meal, which is usually once a day, a meal of champions. Today I had leftover pork roast, collard greens, pumpkin walnut casserole and a sliced avocado.I used butter and coconut oil. I tell ya, it was delicious.I had one serving of everything. I did not overeat. But I did clear my plate so that I could make it through another fast…That’s exactly the way Grok would have done it.

    Mary Titus wrote on March 15th, 2012
    • Recipe for pumpkin walnut casserole, please! Sounds yummy.

      lulu wrote on March 17th, 2012
  37. O.K. The last time I seriously fasted was before Vatican II reported out. I’m convinced based on your writing that it can help me. I’ve been trying to stay Paleo/Primal but cheat a good deal. I’m going to try it because:

    1. I think it will make me eat really great quality Paleo food on the non-fasting days.

    2. It will save me time in the kitchen.

    3. It will save me money.

    4. I’m not overly active now, so it’s not like I have to cut back on my activity level.

    5. It will help me lose the “last ten”.

    I’ll be in touch!

    Cindy wrote on March 15th, 2012
  38. i like to think i’m a bit of an old hand at fasting since i’ve been doing it for a month every year since i was a kid :)

    it’s approximately a 12 hour window from dawn to dusk, pretty manageable once you get the hang of it. you do cut a lot of body fat when u’re fasting so it’s a good option for those who have hit a plateau and need to get just that little bit more off.

    naz wrote on March 15th, 2012
  39. I was fasting once, for a week, but not in fat loss purpose. I was trying to cleanse myself.
    The experience was good, I enjoyed sauna once and really felt benefits from it. I was ‘eating’ vegetable soups 3x a day and was doing enema (if that’s how you use the word in a sentence;) in the morning. I can tell you thet this was my favourite part of fasting – emptying my colon. It sounds weird, maybe, but it’s true. :)
    I am thinking on doing it again, the same way I did it before, I just have to gain some courage. I definately would say that it contributes to fat loss, if you go back to eating solid foods gradually (not like I did, on a picnic :P). When I’m fasting the next time, I’ll make sure not to repeat the same mistake again. ;)

    masage wrote on March 16th, 2012
  40. The study on obese patients linked here actually had them consuming 25% of calories on fast days, so it wasn’t a simple eat-don’t eat. They would have been counting calories presumably.

    Katherine wrote on March 16th, 2012

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