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

Why Fast? Part Seven – Q&A

By now, you should be caught up on all the benefits that fasting offers. By now, you’re likely either intrigued by the practice, strongly considering taking it up, or basking in the smug satisfaction that your longtime breakfast-skipping ways weren’t destroying your metabolism after all. But although I tried to cover just about everything I could in the last six posts of this fasting series (links at the bottom of this article), I apparently didn’t hit every angle, because I received a barrage of questions from readers via email and comments looking for clarifications, answers, and explanations. I can’t quite answer them all, but I did manage to put together a fairly representative selection of the most common and relevant ones, and today I’ll provide answers.

I would like to IF but I have osteopenia and am concerned about losing bone mass. I have been gluten/dairy free for three years and paleolithic for about 3 months. Would IF be good for me?

Your hesitance is understandable, as caloric restriction has long been associated with bone loss, likely due to the reduction in circulating IGF-1 (insulin like growth factor 1) levels. Since intermittent fasting does not appear to have the same effect on IGF-1 levels, however, I’d imagine it’s pretty safe for bone health. Just make sure you’re eating enough calories when you do eat (the IF rodents in the study did not reduce calories overall) and lift some heavy stuff now and then, and I think you’ll be good to go.

There was a study that found in utero IF had a negative effect on fetal skeletal development, but you’re not typing this question from the womb, right? If so, amazing!

Won’t IF induce the body to break down muscle to get amino acids for de novo gluconeogenesis?

Let me hammer this point home: Once you become a fat-burning and keto-adapted beast, most of your energy demands will be met by stored fat and ketones, so you won’t need to eat protein to spare muscle. If you are fat-adapted and keto-adapted, fasting (at least IF) is protein sparing. If you DO need to get some glucose for a hard workout, some will come from glycerol (from triglyceride) and some from de novo gluconeogenesis. But you won’t need much from muscle tissue because your glucose requirements have dropped, you are better at burning fats and ketones, and, presumably you are NOT doing a 2-hour blood-letting in the gym.

As I often say, this is NOT the case when you are a sugar-burner. Then you probably DO need some protein to stoke the gluconeogenesis process, and I’d suggest eating a protein-rich meal (see Meat) before you embark on your fast so your body will have plenty of dietary amino acids on which to draw for gluconeogenesis. Of course, this doesn’t apply to all you fat-burning readers out there. To you I say, don’t worry about muscle loss during IF.

Workout intensity? Should I just be a slug during the fast, normal activity (long, slow walks or bike rides), intense workouts? Intense workouts usually make me hungry shortly after.

Long walks are great while fasting. My favorite pastime is an early morning hike on an empty stomach. I typically fast for a couple hours after my resistance training to maximize growth hormone, but then again, these days I’m generally doing bodyweight exercises (sometimes supplemented with a weight vest). Most sources say to end your fast with a workout and eat afterwards. If intense workouts make you hungry, save them for the end of the fast. That way you can derive the benefits of a long fast, the benefits of a fasted workout, and the benefits of a massive feast after it all. Win win win.

Above all, I would stay as active as possible during the fast. Sitting around like a slug will only make you dwell on food, and the lack thereof in your body. Don’t do that unless you want to obsess over what you’re not eating. Walk, ride a bike, get some work done, do housework, read something. Just keep mind and body active.

I am on a regimented meal/medication plan. I am adopting the Primal lifestyle, but I need to make room to allow for the tasting of these products. Sure, the menu items I can handle, as I just really need to take a couple bites, and that is it. The problem comes from having to taste for quality of the other items, like sauces that an employee makes, for consistency sake. In each, I might only have to taste a teaspoon or two at most to correct for seasoning, but when you have 10 items to test, that adds up.

How would you manage something like this? Would you make the working hours like a fast or something, to account for the tasting?

How does a chef fit the Primal Protocol?

Sounds like a great job to me! Personally, I wouldn’t worry a whole lot about fasting, especially as you start a new job and acclimate to a new schedule. Plus you have a family, which can add even more stress (love you, kids). Intermittent fasting might heap another stressor onto your busy schedule, so keep that in mind.

If you’re dead set on it, though, there are two ways you can incorporate fasting into your schedule, as I see it. First option: don’t sweat the tastings. You’re only doing a teaspoon at a time (and you could probably cut that to half a teaspoon, am I right?), and since fasting is not controlled by an on/off switch, you won’t necessarily be “breaking” the fast. Just consider your work day your fasting period. You’ll be on your feet throughout the fast, so you’ll be staying active and your mind will be engaged with things other than food. Er, scratch that: you’ll be engaged with food, but not necessarily eating it.

Another option is to fast on your off days. Assuming you get a day or two off, just do a full-on legitimate fast for one of them. It doesn’t have to be a full 24 hours or anything, but try to make it at least 16 or 18 hours without eating. Good luck!

Are you suggesting that it really is OK to skip breakfast?

Yes, I am. While epidemiology suggests that breakfast skippers are fatter and less healthy, that’s a correlation, not necessarily causation. It could just as easily be explained by the fact that people are more likely to skip breakfast because they’re overweight and want to lose weight. Or maybe because skipping breakfast is widely regarded as an unhealthy activity (like eating red meat), those who are already healthy are more likely to eat breakfast. See how it works? To date, there has never been research conclusively showing that skipping breakfast causes the metabolism to “slow down” or the skipper to gain more weight. In fact, the bulk of the evidence suggests that meal frequency and timing have no effect on weight gain or health (and it might even be the opposite, as my fasting series suggests).

What frequency do you recommend the average guy on Primal/paleo fast?

It depends entirely on the duration of your fasts. If you’re doing a Leangains-esque slightly compressed eating window, daily fasts are in order and even well-tolerated. If you’re doing longer fasts that stretch toward 24 hours and beyond, once a week is all you “need.” Two would be fine, as well, but any more often might make it difficult to obtain enough calories to prevent the negative effects we often see with chronic calorie restriction – muscle wasting, bone mineral density reduction, libido lowering, general malaise.

Can I drink coffee or tea during a fast? How about adding cream or coconut oil to it – will that take me out of the fasted state?

Coffee is actually beneficial for fat-burning, especially during a fast. One study found that an infusion of epinephrine – a hormone which coffee increases – during “starvation” enhanced its lipolytic and thermogenic effects. In other words, fat-burning and metabolism up-regulated in response to epinephrine (more so than usual). Epinephrine also lowers appetite, which can be extremely helpful for people trying to stave off hunger during a fast. Tea, and anything non-caloric, is also fine.

Adding a pure fat source won’t “take you out” of the fasted state, and it may take the edge off the hunger, but it will reduce the body fat you burn by a bit.

One should eat protein and carbs 30-60m post workout to build the muscles. Am I wrong?

If your sole intent is to get stronger, build muscle, and pack on weight – all fine, commendable goals – then, yes, you should eat some protein and carbs within an hour of working out. Of course, this is totally compatible with fasting. Just end your fast with a workout, and feast right after.

I play competitive sports 3d/week. Should one make sure to eat on the days one plays sports? Or is it more important to eat the day after?

Personally, I would eat on game days. It might be fun to try out a few fasted games, just to see how you perform, but the likely optimal way to integrate fasting into competition is to save the fasting days for your training days. By doing this, you’ll be “training low, playing high,” which should result in some beneficial adaptations after training and improved performance in the game (when you’re “high,” or fully replete with nutrients and calories).

Should fasting be considered when you try to GAIN weight?

Usually, no. But there are a couple special cases where fasting might help someone gain mass.

I’ve mentioned Leangains a number of times in the past several posts, and I’ll do it again. It’s right there in the name: “lean” and “gains.” Plenty of people have success gaining lean mass on the 16/8 Leangains IF plan. It’s slower gaining, but it minimizes and sometimes even eradicates fat gain. Of course, you also have to be sure to lift heavy weights and overfeed on training days (most find the two are a natural pairing, though).

I’ve also heard from people who used intermittent fasting to increase their appetite to the point where eating enough calories to gain weight was possible. The constant snacking was keeping them perpetually full, whereas a good solid 18-20 hour fast really ramped up their hunger and allowed them to eat an actual meal.

Can I take vitamins or supplements during a fast?

Sure, but absorption might be hampered without a meal to go along with it. Vitamin and mineral absorption is generally better in the presence of food, particularly fat. For instance, vitamin K2 is absorbed seven times greater when taken with a meal than without (PDF). I personally skip the supplements when I fast.

I’m actually posting this in a fasted state. It’s been about 20 hours since my last meal. Should I keep fasting till I hit the 48 hour mark? I’m not really hungry, but I’ve been doing the one meal a day thing for some time. Thoughts?

Sure, give it a shot. I always say that pushing the limits is healthy from time to time. Plus, this will give you a good baseline. If you know you can fast for, say, 36 hours without doing too much damage or incurring too much stress, you’ll know your limits for the future. People have fasted for far longer and lived to tell the tale, and you seem to be reasonably experienced. Good luck.

Should pregnant or breastfeeding mothers do it?

Probably not. Whatever you do, listen to your hunger signaling. Don’t force yourself to adhere to an arbitrary fasting regimen just because it’s shown to confer all sorts of benefits in other, non-pregnant populations. While I wasn’t able to find any studies on breastfeeding and fasting, there are several on maternal fasting:

There have been studies on calorie restriction and lactation, and it looks like mild calorie restriction (coupled with exercise) has little impact on breastfeeding. If you’re going to do this, make sure your milk quality and quantity aren’t negatively affected. Keep the fasts short (12-ish hours) and infrequent, just to be safe. And, of course, consult your doctor prior to doing it.

Should I fast if I’m trying to get pregnant?

Generally, no. Fasting is a stressor, and if you’re already stressed out over something and cortisol is high (say, because you’re trying to get pregnant and finding it difficult), throwing a fast on top of that will likely compound the problem and make it harder to get pregnant. Cortisol is a potent inhibitor of fertility.

However, if you find that fasting improves your health, reduces your weight, enhances your metabolism, fixes your metabolic syndrome, which can all have negative effects on fertility, it will likely have a net benefit. If you intend on fasting, opt for the “WHEN” method rather than a regimented one, and keep your fasts pretty short. Fertility requires “plenty.” An extended fast does not exactly send that message to your body. A 12 hour fast every once in awhile should probably be the limit, and only if it’s improving other subjective and objective markers of health.

On the other hand, men who are trying to impregnate someone may find it helpful to fast.

Should kids do it?

Kids shouldn’t be put on a fasting regimen or anything like that, but they might forget to eat now and again, and that’s totally fine. As a kid, I often spent my summer days in a fasted state from early morning through early evening, simply because I was out running around, playing capture the flag, skipping rocks, and generally getting into trouble. It didn’t always occur to me to eat. I think I turned out okay.

Should seniors do it?

Seniors should absolutely try it. Although we’re talking elderly humans here, elderly rats derive a lot of beneficial neurological effects from intermittent fasting. I see no reason why older folks can’t also enjoy the neurological, life-extending, and health-promoting benefits of fasting, too. It might increase healthspan, stave off age-related cognitive decline, and improve quality of life.

Under what circumstances would you recommend that someone not fast?

High stress. Overtraining. Chronic lack of sleep. SAD dieting. And then there’s my previous take on the subject.

I’m thinking about giving IF a try and am wondering if you have any thoughts on how to track its effectiveness. Would you recommend a logbook? What should I be recording and looking for?

I think for many people looking to track the effectiveness of a given fasting protocol, a logbook can be extremely helpful. Think of it like a training log for your workouts. You can track:

  • Objective measures, like weight, body fat percentage, waistline, blood sugar, dress size, hours slept, plus markers of physical performance, like weight lifted, reps completed, distance run/walked/cycled/rowed. These are easy to track, as they come with numerical figures built-in.
  • Subjective measures, like mood, energy levels upon waking, energy levels halfway through the fast, energy levels during workouts, perceived performance during cognitive tasks. These are trickier to track, so you may want to assign numerical figures to them in order to quantify what is essentially a subjective measurement. Something as simple as rating your mood 1-10, with 1 being “very bad” and 10 being “very good,” should suffice.

And if you’re fasting for a specific health effect, say to boost the effectiveness of chemotherapy, you’ll definitely want to track those specific health markers.

Ultimately, what I hope this series has done is inspire you to self-experiment with fasting. I always maintain that fasting is not essential to Primal living, but it certainly seems to mesh well with it. Whatever you do or don’t do, I want to stress something: don’t stress out over this stuff. If you’re going to give it a shot, do so and do so intelligently – by tracking your progress, maybe even doing so formally – but don’t drive yourself crazy obsessing over the minutiae. Whatever you do, good luck!

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. Thanl you for the piece about trying to get pregnant. Fertility is an issue with me, on of the reasons for going primal recently. I was considering IF but now I will just listen to my hunger signals

    Primalmontana wrote on April 27th, 2012
  2. I’m doing an alternate day fast. I’m 42 and weight around 245. How mmany calories should I get on non-fasting days to avoid the negative effects?

    Dave wrote on April 27th, 2012
  3. “Adding a pure fat source won’t “take you out” of the fasted state, and it may take the edge off the hunger, but it will reduce the body fat you burn by a bit.”

    Can you define ‘a bit’? Would adding heavy whipping cream really stunt my efforts if I give IF a try? I mention this only because I really can’t stand black coffee and adding cream does make my coffee more palatable.

    Tim wrote on April 30th, 2012
  4. Tim, good question. There are many views. Since a major benefit of fasting is rock-bottom insulin levels and fat is the only food to not stimulate insulin, I think adding some cream is not going to be an issue. sure, you are supplying calories, but I’ve noticed a small amount of grass-fed butter makes fasting “easier” for me, while having nothing is much harder. I don’t think a small amount of heavy cream is going to affect you negatively, just don’t use milk, half-half or something else that could cause a rise in insulin. However, you are burning less stored bodyfat if you are adding calories, but you are still burning fat. As other’s mentioned, it’s not a pure fast and anything added (such as the antioxidants in coffee) may turn off certain autophagy processes, but if its between not doing it and doing it, add the cream, especially if you are doing it frequently like LeanGain, Fast-5. You could also go read up on Bulletproof fasting at which includes adding fat to coffee.

    David wrote on May 3rd, 2012
  5. Greetings, I aim to detox my system and one large goal is to rid myself of as much excess weight as possible. I’m 29, 5’5′ and 165lbs- I should weigh around 130lbs. I maintain a generally healthy lifestyle and have even been vegan. This being said, maybe I was just not patient enough with the process, or rather, I hit a plateau which makes me look to fasting. I am determined get rid of this load and am ready to fast until my end objectives are reached. This being said, I want to know of any benefits and disadvantages to “phase fasting” (I just coined a new term). By phase fasting, I mean breaking the process of massive weight reduction into parts, i.e. 1 week-month of fruit/veg smoothies, next week-month raw juices, followed by a week-41 days of only water. I figure that this will allow the body to adjust to the process and as well as mentally prepare one’s self to abstain from food all together during the final phase. This makes total sense to me, but I havent heard this style discussed. THANKS FOR SHARING YOUR OPINIONS and FACTS!

    Raina wrote on July 1st, 2012
  6. I’m currently doing the 16/8 IF and i feel amazing! strength is still up and fat is melting off! My work schedule is from 3am to anywhere from 1-3pm, I normally workout after, but keep in mind that i start my fast around 7pm the night before. I’ve been doing the 2 small meals before. I am trying to preserve muscle yet burn fat, is this a good way to go about it? any suggestions would be awesome !!

    Oscar wrote on July 4th, 2012
  7. I have been living primal for about 2 ½ months. I’m not sure if I’m completely fat-adapted yet but my weight loss has hit a plateau. I’ve been reading up on IF and have done one 24 hour fast. I felt fine. I think it’s more mind over matter. I read about the 16/8 method and I kind of like that idea over the 24 hour. I’ve been doing the 16/8 for about a week now. I never workout in a fasted state because I break the fast at 1 pm and my last meal is no later than 9 pm. I am not a morning person. Since going primal, getting up in the mornings is easier but I still don’t have the energy to workout in the mornings. I notice that I’m not eating as much when doing the 16/8. I think I feel like I’m eating too fast or too much just because it’s for a shorter period of time then the norm. I would like to know if there is a specific amount of calories I should make sure I’m consuming everyday so I don’t do more harm than good to my body. Thanks for the help!

    JenSmith wrote on July 10th, 2012
  8. Hey I got a question, since its summer im doing the IF, but I got a problem. I decided to make my window from 3pm-9pm but because its summer ive been waking up late, on my way to fixing that. But my question is if I sleep most of the time when im supposed to be fasting such us sleeping until 1pm, will my IF be useless if I was running on the 3pm-9pm window. I know its kinda of a dumb question considering you arnt doing much while asleep but just wanted to clarify. Im really glad you introduced the IF, think its a great idea, really similar to Ramadan for us Muslims. Thanks.

    Maziad Al-Abdul Wahid wrote on July 11th, 2012
  9. Hey I got a question, since its summer im doing the IF, but I got a problem. I decided to make my window from 3pm-9pm but because its summer ive been waking up late, on my way to fixing that. But my question is if I sleep most of the time when im supposed to be fasting such us sleeping until 1pm, will my IF be useless if I was running on the 3pm-9pm window. I know its kinda a dumb question considering you arnt doing much while asleep but just wanted to clarify. Im really glad you introduced the IF, think its a great idea, really similar to Ramadan for us Muslims. Thanks.

    Maziad Al-Abdul Wahid wrote on July 11th, 2012
  10. Just wanted to add some info for women who are fasting and trying to get pregnant. I had always had trouble getting pregnant. It took me a year and a half to get pg with my first. Before getting pg with a second I wanted to get in shape first. I had been trying to lose weight and was not preventing pregnancy for 5 months. It wasn’t until I started intermittent fasting that I got pregnant. I had been IFing for a month, and it happened right away. I felt a little guilty, like I had been depriving my baby for those couple of weeks, but it certainly did not prevent my pregnancy.

    Kristal wrote on July 17th, 2012
  11. is it ok if i jog or walk on treadmill for about 30 min in the morning and then do high intensity weight lifting from 12 to 1 and eat three meals from 1 to 9 ????

    how does this sound ? and can i maintain the same intensity at the gym or should i lower it down ?????

    prasanna wrote on July 28th, 2012
  12. Is there a danger that intermittent fasting would cause your body to go into starvation mode?

    Thank you

    eddy staes wrote on August 7th, 2012
  13. I have a bit of a quick question- i’ve always been using the carb cycling and keto method of dieting and after reading up on IF, i’m going to give it a shot, but i’m a little stuck with nutrients.

    All the calorie calculators online show some sort of measurement in grammes, then the calorie equivalent. Trouble is, this doesnt really tie up with a lot of foods.

    For instance, a tin of tuna is 30g protein, but calorie wise is only 130 calories. I understand I need to be in a slight deficit to lose weight, but i’m wondering how I keep up the nutrient balance if I cant get the amount of calories I need from my protein sources without introducing lots of fat.

    How does this work?

    If for instance, I have 5 pieces of wholemeal, a tin of tuna and an apple, thats only about 430 calories, yet I should be getting around 530 to keep on track. The carb/protein balance is correct for my weight, yet I am still low on calories. Should I just be adding in the remainder as fat, like a handful of nuts or something?

    I want to try and make this as easy as possible and i’m struggling!

    Great website btw, lots of good info :-)

    Alex wrote on August 10th, 2012
  14. Hi i have been doing 24 hour fast and i find it really weird that i am able to get through my fasting days just fine i go through the 24 hours and if i wanted can probably get up to 36 hours, but on non fasting days when i wake up at 7 ish and eat breakfast between 8:30-10:45 i will be ravenously hungry and craving everything the rest of the day and end up eating more.

    Tara wrote on October 9th, 2012
  15. I’ve been fasting for a full week with 24 hour increments and feel fantastic. I’m actually down a number of lbs and have no plans to stop. The day time hours can be challenging, but I’ll usually have a cup of vanilla nut (decaf) tea mixed with a couple of tablespoons of apple cider vinegar (0 calories) and some ground cinnamon. No sweetener. Tastes like a hot cup of apple cider to me. Delicious. I also take a number of multivitamins and omega 3 capsules. I usually chug water all the way till dinner time, 1 hour time limit for dinner (usually vegetables, protein and one or two fruits) and then Bob’s yer uncle.
    Water until bed time. Not having food in the morning is incredibly liberating.
    I’m finally off of the roller coaster ride of insulin spikes and cravings. I do hope this is a lifestyle that I can stick to.

    Marie wrote on January 23rd, 2013
  16. I loved this series on IF. I’ve been curious about it since watching eat, fast, and live longer. I’m not really overweight, never have been. In reading this though I realized that I have been using IF on my own and just never knew that it had a name. Most days I would not eat from say 1am until 7pm or so. If I felt weak or nauseous before evening I would eat something, but I didnt often need to. I also tend to not eat alot of meat, but love veggies and fruits. I do like carbs and potatoes but even those I dont eat much of. My real weakness is sugar. Soda, coffee, tea…if it isn’t sweet, I don’t drink it. oh and milk, not sure if milk is good or bad, but I love it. should this way of life affect me positively? If so, how?

    Hannah wrote on April 4th, 2013

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