Monday, November 23, 2009

Questions & Answers

It's time for another Q&A session.

Intermittent fasting and women

Q: I'm a bit confused. Some people say I should do 16 hours of fasting, while others say that you now recommend 14 hours for women?

A: Females do 14 hrs fasting by default. The fast typically lasts 16 hrs, and is usually initiated in the evening. So in practical terms you might have your last meal some time between 8 and 10 pm in the evening and break the fast around noon on the next day.

But for women my default approach is to actually start off with 14 hrs and see how they do on that before eventually moving them to 16 hrs. When you look at the studies on gender and fasting, you tend to see that women may have slightly more adverse reactions to fasting than men, such as some degree of irritability and increased attention to food cues. 16 hrs is hardly prolonged fasting, but I like to play it safe, so that's why I have female clients fasting for a shorter time at the beginning.

Intermittent fasting at higher body fat percentages

Q: All the guys I've read that have tried this, are all lean, I mean, if you're that lean already, going on a keto diet would do exactly what intermittent fasting would do to YOU. Id like to see someone over 20% bodyfat share his experience.

A: Not at all. I have many clients with 20% body fat or more and they are doing great. Some of them are, for the first time in their lives, finding that they can show 100% adherance to a diet protocol.

I modify the caloric guidelines and macros depending on body fat %, as my first priority is always to lean people down if necessary. Besides that, I don't see how body fat would play into making or breaking an intermittent fasting diet.

There are many psychological sides to eating. I think smaller and more frequent meals throughout the day, even if they are low carb, may be a bad choice for some people; acting as a trigger for cravings or increased appetite, for example. A conventional high frequency "nibbling" approach is working against their weight loss efforts. It's often counterproductive.

But knowing that you can have a substantial meal after the fast makes dietary adherance very easy according to many of my clients. In my experience this is one great benefit to intermittent fasting that caters specifically to people with a higher body fat. They are big eaters, so they like to eat big. Intermittent fasting fills that need.

Intermittent fasting, mood and appetite suppression

Q: I remember you saying something about a minimum time for the fast ... like 12 hours ? After that point "stuff" started happening ?

A: Hours 8-12 are pretty neutral. Not noticing much. Sometimes I get a short hunger pang, which disappears rather quickly and is replaced by total absence of hunger.

Hours 12-16 I get a sense of focus and wellbeing. I feel inspired and involved in whatever I'm doing (usually working on consultations or writing articles). Call it wired if you will. The thought of food remains unappealing until the very last hour. Most people experience the same effects in the same time interval.

Intermittent fasting and regular meal patterns: mixing it up

Q: What's peoples experience with intermittent fasting on the week days and a "regular" diet on the weekend or something like that? I think that would fit my schedule perfectly, especially since i am much more active on the weekend and play sports/do cardio sometimes multiple times and very spread out.

A: Eating on regular intervals each day has it's benefits. Breaking the pattern may screw a bit with the ghrelin pulse. Ghrelin is a hunger hormone which rise in anticipation of a meal and is in tune with your day-to-day meal pattern. This is also part of why you can go for 16 hrs without getting hungry once you get used to it.

Practically, this might mean that it could be a bit harder to get back to fasting when you break the pattern (weekends). On the other hand, I've done it personally many times and I haven't experienced any problems at all. Fasting is still very easy after a day of more regularily spaced eating. It might take several days of a new meal pattern before a new ghrelin pulse pattern develops, so go ahead and try it.

On breaking the fast

Q: I break the fast with a large bowl of oatmeal and a whey shake, and have noticed I get a bit drowsy shortly after the meal. Any suggestions?

A: While I don't know the particular macros of your meal, I would wager it's fairly insulinogenic and provide a substantial glycemic load - and that may be the problem. Ditch the whey shake for whole food protein such as meat or eggs, and oats for something along the lines of veggies, beans and lentils (or other lower glycemic index foods with a decent amount of fiber). If you must, you can have your oats and whey post-workout instead.


popmusicmiguelangel said...

I Personally prefer to not eating a solid meal or a medium size meal pre workout, because just when i start to eat, i cant stop till im completely full, so i just take some whey or fat free cultivated milk that has 22protein-36carbs-4 fat.

jamie hale said...

"Hours 12-16 I get a sense of focus and wellbeing."

At about hr 16 i get a similar feeling, and hunger disappears.On a couple of occassions I have fasted for 30 hrs plus, and felt no hunger and experienced increases in cognitive functioning and performance. But i was drinking a fair amount of caffeine while fasting, which probably made a huge difference.

jamie hale

Anonymous said...

wow what a coincidence i experience the same thing! i get super productive during the fast like very sharp and focused. i wonder why though??

Anonymous said...

I read its because fight-or-flight hormones that boost your metabolism and thinking ability. I think Martin wrote it somewhere. I dont know but Im also much sharper mentally during the fast. Good time to study.

Anonymous said...


This question is in regards to the question about the potential for IFing during the week and "regular" eating on the weekends and even a small possibility of interference with ghrelin pulse patterns.

Do you find that certain people are able to be so discipline/robotic in terms of how they approach food intake that even with a somewhat varied pattern of feedings on a regularly (even daily basis) they are able to deal with hunger caused by ghrelin pulses and go with whatever eating pattern is the best fit on that day?

I am not sure if I articulated this very well, but I find that while my daily intake is always roughly the same in terms of kcals and macros, the patterns in which I consume it can be rather haphazard depending upon that day's schedule. I often feel like I am on auto-pilot and can override just about any degree I am apt to experience under relatively "normal" circumstances.

Just curious if you have deal with a number of people who never seem to let hunger get to them.


Martin Berkhan said...


Sure. Tends to be busy people tied up in work. So the question remains whether it's because they're so wrapped up in whatever they're doing, or whether it's because they have an edge when it comes to ignoring hunger signals etc.

When you're busy, and when the work you're doing is challenging and stimulating at the same time, time passes quickly. You easily forget to eat even if there is a true physiological need (as signaled by ghrelin).

Martin Berkhan said...


'i get super productive during the fast like very sharp and focused. i wonder why though??'

From another post -

The fasting aspect of the diet has several positive effects on lipolysis, partly mediated by catecholamines and growth hormone release during the fast. Besides acting as an appetite suppressant, the catecholamines provides a stimulatory effect. You will most likely feel like you have more energy and focus than usual. In this state any other stimulants, like caffeine for example, also has a more potent effect in comparison to being consumed on a full stomach.

Martin Berkhan said...

I should add that it's norepinephrine in particular that enhances focus/mental sharpness.

Anonymous said...

hey thanks for answering martin! great site

Grok said...

Hour 20 is by far my favorite. I feel almost superhuman during that hour.

I've been at this for a while, so less than 18 hours I don't even call them fasts anymore. Those are skipped meals in my logs.

Anonymous said...

I'm trying to figure something out. Would I be okay avoiding a pre-workout meal if I'm only doing about 700 Cals worth of LSD energy expenditure work as my workout? My first/pre-workout meal is at around 3:00 PM and is about 300 Cals (1 apple, 1 schoop whey, 1 cup milk).

Martin Berkhan said...

LSD-workouts must be quite a trip.

On a more serious note, I don't know what you mean.

Jon Fernandes said...

"Hours 12-16 I get a sense of focus and wellbeing. I feel inspired and involved in whatever I'm doing"

Martin, you so right. because of this effect i get from fasting, i have so much more motivation in my life to move on with my health career.

I would also like to thank you for introducing to all of us this nutritional program. IF has fixed a lot of health issues i was having. two biggest ones being:

1. Hypoglycemia - IFing has made me super-carb sensitive. i feel so much more better on carbs now. i can actually enjoy food again.

2. Legarthy/asthenia - IF has made me feel so much more alive its ridiculous. For some reason now, everyday to me an exciting adventure. I have been so much more motivated to help people. i enjoy doing it from the heart. Who knew IF can change a person throughout. I feel so much more positive about life now.

Thank you Martin. You are one of the few people who have changed my life.

P.S. - i would like to do direct consulting with you soon. i will send you an e-mail when i am ready.

Martin Berkhan said...

Hey Jon,

thanks for the kind words and the feedback on my approach. I'm glad to see it's been working so well for you. Lots of people have seen the same improvements wrt insulin sensitivity btw.

Eddie said...

Hi Martin,

Thankyou for sharing this information. Just a quick question I hope you can clarify for me regarding calories when adding mass. On workout days you recommend to eat more than maintenance calories, and on non workout days to stick to maintenance/below maintenance by cutting down on carbohydrates. As there will still be an overall suprlus in regards to calorie intake can this still lead to a loss in bodyfat?

Your help is greatly appreciated.

Martin Berkhan said...

It can, yes. By definition, you'll need to go below maintenance on rest days for that to occur. Well, theoretically if you were to add only lean body mass, body fat percentage would go down. But obviously, such results would need some time to manifest.

Raidho said...

Hi Martin, great post and information as usual. What are your take on bodyweight exercises done fasting? I'm looking for some variation in my morning LISS workouts, and adding some easy bodyweight exercises (pushups, lunges, squats, stability-ball exercises, assisted chins, dips and rows) would be great since I love doing them. My question is, are they low-intensity enough?
Keep it crackin'!

Martin Berkhan said...

Unless you're doing considerable damage to the muscle fibers by going to failure on weighted dips, chins or pushups, you will be fine. I'm also assuming you're not working out long enough to cause substantial muscle glycogen depletion.

Raidho said...

No, I'll just go with my own bodyweight, just to get some blood running and lubricating the joints without raising HR to much. I just want to wake up the muscles and get in contact with my whole body. Great to hear, thanks for your advice!

clifton said...

I like coconut cream in my you think this is an deal breaker for the fasting? Also, I'm going to try for a couple weeks of doing coconut oil in the a.m. with my morning tea....I like all the health benefits of coconut oil....and think that it may help to get the fat burning engine going even greater during the fast? whaddya think...or is that just reaching?

clifton said...

BTW...both my roommate and I had dramatic below the belly button fat loss in 3 weeks of following the 16-18 hour fast, with one 24 hr fast a week.

Martin Berkhan said...


Max 50 kcal in the fasted state.

"and think that it may help to get the fat burning engine going even greater during the fast? whaddya think...or is that just reaching?"

Not "reaching", just plain out wrong.

Anonymous said...

Hi Mark.. I havent seen too much on your blog for women. Do the same guidelines appy to us? as far as workouts? i have been fasting for about 4 months now and have plateaued. i also am a crossfitter. do you think i need to start lifting really heavy like you suggest? to failure? Thanks for being so ripped.

G said...

Hi Martin,

I'm a 32 year old women, and I have been plateauing for couple weeks now after loosing about 20 lbs and 4 % body fat in 5 months by increasing my protein intake and cutting way down on sugar. I find your information very interesting, and did my first 14 hours fast this morning. But I don't find much for women on your site. In the long run, I understand that this is a lot about calories. Is there a way I could figure out what it should be on days I fast?

Cheryl said...

Thanks so much for this site and all the information - I have been doing the 14-16 hour fast the last few days and I am finally noticing a drop in weight, plus I do seem to be clearer in the mornings. Its mostly the psychology of it that is difficult - I am so used to popping out of bed, brushing my teeth, and then making myself breakfast.

Kevin Brandthout said...

Hi Martin,

I am following your fastened training protocol but I just noticed I'm actually taking twice the BCAA you recommend.

I take 10g of neutral (NSI brand) BCAA before my workout and drink 10g of Purple Wraath during my workout.
Should I scratch one of them or is this fine?


My name is Martin Berkhan and I work as a nutritional consultant, magazine writer and personal trainer.

Welcome to the Internet's leading resource on intermittent fasting and all things related.

FeedBurner FeedCount

Google Friend Connect

Join Me on Twitter


Follow Me on Facebook

Recommended Reading

Lame Title, Good Book

Recommended Reading

Intermittent Fasting for Fat Loss

Recommended Reading

Covers All Bases

Recommended Reading

Awesome Recipes for The Paleo Diet
Recipes for the Paleo Diet - Two Cookbooks - 120 Recipes Each!>

Recommended Reading

Fat Loss Made Easy

Great Interval Timer

+1 If You Think Leangains is Awesome