Wednesday, March 17, 2010

Intermittent Fasting, Set-Point and Leptin

I ranted a little about diet approach, leptin and the set-point theory on

Figured it could make for a decent post here. I added some extras in the form of a short review on the effects of intermittent fasting on leptin.


Short background on leptin and set-point

Leptin is a master-hormone with downstream effects on other hormones related to metabolism (T3/T4, neuropeptide-Y, epinephrine, among many others).

In the long-term, leptin is regulated by total amount of fat mass. A drop in leptin affects the other hormones negatively and vice versa. Low leptin leads to an increase in hunger and a decrease in metabolic rate, much like high leptin leads to a decrease in hunger and an increase in metabolic rate.

Generally speaking, lean people have low levels of leptin while obese have high levels of leptin. However, in the latter case, leptin resistance develops. This is likely an effect of chronically elevated leptin, much like insulin resistance is an effect of chronically elevated insulin.

The set-point theory of body weight-regulation is intimately connected to leptin and has a strong genetic component to it. Naturally lean people maintain a low body fat set-point by being leptin-sensitive; they can maintain a low body fat percentage and function optimally even with low leptin. But most of us aren't so lucky, which is why getting really lean is typically a difficult task.

Dieting in the single digit body fat-range

Lyle McDonald paints a dark picture of life in the low body fat percentage-range. Yet I and my clients maintain a low body fat % without any of the often cited symptoms, such as anhedonia, low libido and a general sense of weakness. It's hard to argue against the literature on the topic, since it's substantial and shows that these side-effects indeed occur. However, it bears mentioning that the studies looking at leptin levels after dieting are limited in the sense that they often use conventional dieting strategies that entail a pronounced weekly calorie deficit for both men and women.

I too experienced the aforementioned side-effects in the past, That is, before I finally "got it right." What does that mean exactly?

Me at a skinny 165 lbs. Editorial work in Milan. My approach to dieting back then wasn't exactly ideal.

During my last cutting diet, that is the one that took me to 5.5% where I have hovered ever since, I did the following things right:

1. I lost the final pounds of fat very slowly and the weekly calorie deficit was subtle. The scale moved down as slow as one pound every other week. On the other hand, I barely felt like I was dieting and I maintained strength and muscle surprisingly well.

2. I was able to make a smooth transition into maintenance. I did not count the days until the diet ended, and I did not sit and plan a big refeed to celebrate when I was done. I didn't feel deprived, daydreaming about food.

3. I would do a extremely controlled and modest refeed 3x/week or 3x/8 day (on training days).

Now contrast this to what I did in the past, which caused me to feel miserable during the whole process and experience rebound weight gain:

1. I wanted to lose as fast as possible so I could work on muscle gaining. The weekly calorie deficit was fairly substantial given my already low body fat percentage - I was losing in the range of 1-1.5 lbs/week. I felt deprived and just wanted to get it over with. Strength and muscle loss was substantial.

Another one. From a shoot in M√ľnich. Weight around 165 lbs or so.

2. I would sit and plan my big refeed meal at the end of the diet. I would count every day like an inmate counting the days to his release from prison. And once I reached my goal, I would go bonkers, eat a bunch of crap, take several steps back and then go back to dieting in a feeble attempt to make up for my screwed up "refeed" (aka binge in my case).

3. I did no refeeds during the diet.

So what's the lesson here and how does it relate to the topic at hand?

Leptin: science versus real world

Leptin is controlled primarily by two things, which are

a) Short term: acute energy balance. A high calorie deficit causes leptin to drop lower than what can be explained by fat loss, and a caloric surplus raises leptin higher than what can be explained by fat gain.

b) Long term: total amount of fat mass. Fat cells are factories for leptin production. Not having many factories obviously impairs production and the aboslute amount of leptin in circulation.

If A can be manipulated via a subtle energy deficit and regular refeeds of the right macrocomposition (carb refeeds acutely increase leptin, while fat has no effect), this should prove beneficial to circulating leptin levels during the diet. It might prove fruitful to "trick" the last few pounds of fat off while venturing into the single digits. Another cyclical diet that has much in common with this strategy is The Ultimate Diet 2.0 though I'm in favor of more frequent, more modest, refeeds and no glycogen depletion outside what occurs with a low-moderate training volume.

If anecdotal reports mean something, this is my standard approach for clients and it's working well. I'm not an isolated case. For example, have a look at Andreaz in this post on maintaining low body fat. And we're no ectomorphs by any means. I grew up fat. Science dictates I wouldn't be able to stay this way (low body fat) without feeling completely miserable, but that's just not the case. The avatar pic was taken at the end of 2007, and I've stayed that way ever since. But I failed many times in the past. Only when I learned patience did I attain my goal.

Now, this little theory of mine, that fat needs to be lost very slowly in the single digit range, still leaves questions as it pertains to B, which is that leptin is ultimately controlled by total amount of fat mass.

Several years and 30 lbs later, I finally "got it right".

Low fat mass equals low leptin. Can leptin sensitivity increase if weight is maintained on a low body fat % for a prolonged period of time? Sadly, there are no studies to suggest that for the time being. Can it increase through other means? Well, exercise and fish oil seem to improve leptin transport, so there's that.

But what I think people really want to know is how intermittent fasting affects leptin levels and there's some interesting research on that topic.

Intermittent fasting and leptin

Generally speaking, studies show a neutral effect on average leptin levels during intermittent fasting. While the fasting period decreases circulating leptin, this is compensated by a big boost when refeeding. In comparison to conventional meal frequencies, intermittent fasting induces a "peak and valley"-pattern in leptin synthesis. Leptin secretion is thus entrained to the meal pattern and shifting meal timing causes a comparable shift in plasma leptin rhythm.

However, there are some interesting discrepancies here in that women actually show a big increase in mean leptin levels during intermittent fasting. This occurs even in the absence of weight gain which is all the more fascinating. In the quoted study, despite calorie intake being elevated in comparison to baseline intake, the women actually lost weight and lowered waist circumference and body fat percentage. Intermittent fasting was also shown to decrease neuropeptide-Y, a hormone that stimulates hunger. This could probably be explained by elevated leptin levels, but there was no linear correlation between the two in this case.

Similar effects have also been shown to occur in men. That is, fat loss occurred without any reduction in leptin - and these were fairly lean athletes to begin with.

Intermittent fasting may also be of benefit when dieting in the single digit range due to the effect of fasting on the fat mobilizing hormones epinephrine and norepinephrine. When you’re in the single digit body fat range, you’re likely to have low circulating levels of leptin. One of leptin’s downstream effects is on epinephrine and norepinephrine output. Low leptin equals impaired output of the aforementioned hormones. This is part of how leptin regulates metabolic rate. However, it seems that these hormones increase regardless during fasting. That is, leptin is not able to exert it’s usual power over these hormones. In this case, their increase cannot be mediated by leptin which allows fat mobilization to go on unabated during fasting.

That's it for now. There's plenty more on this topic, but I'll save that for some other time.


* Fat loss in the single digit body fat-range needs to be slow and tempered. In my experience, this allows for a smooth transition into maintenance and minimizes muscle loss. I also believe it might lessen the negative effect of dieting on leptin, which ultimately makes maintenance of low body fat achievable. I think most people diet too hard, which has a profoundly negative effect on leptin - and this is part of the reason why the weight gain rebound is so common in folks who finally manage to reach their goal (and then screw up everything by binging).

* Planned and regular refeeds should be in place. This affects leptin positively and allows for maintenance of muscle and strength. Even if your goal ultimately is fat loss, entering an anabolic phase with post-workout overfeeding will serve you well.

* Intermittent fasting seems to have interesting effects on leptin synthesis. Whether this has benefits for low body fat maintenance or circulating mean leptin levels is up for speculation for the time being.


For more on leptin and set-point, read this and this. I've also talked about the effects of our obesogenic environment on set-point and weight regulation in this post. Somewhat related to the topic at hand, I've also posted on strategies for maintaining low body fat.


Jon Fernandes said...

I have been wondering when you were going to write an article regarding leptin and IFing.

In about two weeks, I am going to be cutting with EOD refeeds but with a less drastic calorie deficient on off days. Going to keep carbs in everyday as well for thyroid reasons.

PSMF days are effective for fat loss but I end up crashing too soon. My mood and energy levels end up being all over the place as well lol.

Thanks for the information Martin.

- Jon

Pikku said...

Another awesome post. Keep up the good work Martin

Anonymous said...

Hi, Martin.

Outside of working with someone one-on-one, is there a resource or a combination of resources that you'd recommend to someone who wants to learn about properly setting up and individualizing re-feeds?

My brother is a trainer, and we were recently having a conversation, and he mentioned to me that he'd like to start becoming more proficient on setting up diets for clients. While I see a lot of various groups coming out with their own made-up nutritional certifications and plenty of so-called experts (read "folks who like to fancy themselves as being of your caliber but who aren't even within several thousand miles of your zip code", to put it politely.

While I understand that no one resource or even group of resources can transform a person into an instant expert, I'd be interested in hearing what might be on your short list for becoming very competent in this area (as well as any other steps you feel are key to developing into a very solid voice in this regard, if not an expert someday).

Any thoughts would be greatly appreciated, and thanks for letting me ramble a bit!

-Shen Liu

Ryker said...

Great post, Martin. Though one of the studies you cited ( seems to show that insulin levels go up on IF. I assume that's not a good thing, since you want to keep it down. How would you comment on that?

Martin Berkhan said...


Hard question to answer without listing numerous potential resources, but first of all I would recommend getting a solid and unbiased perspective of nutrition and exercise physiology. The texts you should be reading aint the ones you'll find on blogs and internet-sites/forums. Advanced Nutrition and Human Metabolism by Gropper and McArdle's Exercise Physiology are both good resources in this regard. As for more "layman"-like material, Lyle's books have plenty to offer.

Martin Berkhan said...


Insulin was only increased compared to the baseline period (pre-Ramadan), which can be explained by the simple fact that daily calorie intake increased during intermittent fasting (...and yet strangely, they lost body fat despite higher insulin and calorie intake).

John said...

So even with a high-intensity, low volume, low cardio training regimen, high carbohydrate meals are helpful/necessary in continuing to decrease or at least maintain an already low body fat...are the high carb meals necessary even if performance does not decrease?

Martin Berkhan said...

Necessary no, helpful yes.

Anonymous said...

Excellent read. Thanks.

Eric Komans said...

I had been dying to see some modeling pics ever since I read about your time modeling in your 'transformation' story.

The whole reason I'm trying to lose, myself, is for an acting career. I was curious to see what you had looked like when just getting rid of boydfat was the goal.

Thanks for the post overall, though! I love your writing.

Martin Berkhan said...

Thanks, Eric. I'm glad to hear you like my writing.

Got plenty more pics from back in those days. Might scan and add them later for shits and giggles. Funny thing is that I was generally considered "buff" (by my agencies and the other models) at that weight.

Sterling Purdy said...

ALWAYS good stuff Martin. It's interesting that leptin's response and attributes differ with IF. It seems yet another reason IF is so beneficial and would benefit those with diabetes even more, especially considering many are leptin resistance or approaching leptin resistance.

Manveet said...

Man were you skinny.

6'0 and 165lbs?


Martin Berkhan said...

Hah yeah. 6'1 actually. Skinny as a rail.

Thanks, Sterling.

Anonymous said...

Great post. Really interesting...thanks Martin!

Anton Kinnander said...

Interesting as always Martin.

- Anton

Mark said...

Hey Martin,
Great stuff as usual. I just wanted to verify what I thought you said in a comment from a prior blog post.
While fasting, I think you said that it is ok to add cream/milk to your morning coffee as long as you do not exceed 50 calories. This way you won't come out of the fast metabolically and you don't have to drink black coffee. Am I right in thinking this?

Martin Berkhan said...

Yes. The fasted state (low insulin) is not something you immediately exit or enter. Splash of milk/cream for your coffee will have such a minimal impact on insulin that it's no use making a big fuss out of it. I said 50 calories max to safeguard against people using boatloads of the stuff which is obviously not ok.

Matt Stone said...

Excellent presentation of your points Martin. I'm liking it. My experiences with low body fat percentage has certainly been negative. At 3-4% body fat I did some major damage to myself, and experienced all of the Lyle McDonald-esque symptoms.

I believe that insulin resistance is controlled primarily by leptin though. In my research I've been led to believe that having LOW functional leptin (either through leptin resistance or actual low leptin) causes insulin resistance, and raising insulin lowers insulin resistance. This is why, when underfeeding, it becomes increasingly easy to gain weight and post semi-starvation blood sugars soar much higher than pre-starvation levels. Likewise, weight loss is easier than ever after overfeeding and post overfeeding blood sugars are lower.

That's also why fructose, which doesn't raise insulin, is so fattening. Glucose raises leptin and lowers insulin resistance, which is probably why an extremely high carb/low fat diet lowers fasting insulin by "30-40% in 3 weeks" according to guys like Joel Furhman. His latest blog post today is of a man who lost 333 pounds on his diet. You could hardly say that carbs cause insulin resistance when his diet is roughly 75-80% carbohydrate.

Amen to carb refeeds by the way.

Lastly, I've always rolled my eyes at IF-ing. It's use in altering leptin, however, will keep my eyes wide-open from now on.

Keep up the good work Martin. I'll be paying attention.

Anonymous said...

"Low leptin leads to an increase in hunger and metabolic rate, much like high leptin leads to a decrease in hunger and increase in metabolic rate."

Think there's a word missing in there, otherwise you're saying that low and high leptin levels both lead to an increase in metabolic rate.

How would you define a "modest refeed"?

Anonymous said...

Martin -

You said:

"The fasted state (low insulin) is not something you immediately exit or enter."

Does that mean one would want to avoid BCAA supplementation during the fasted state due to the insulinogenic effect?


Martin Berkhan said...


'I believe that insulin resistance is controlled primarily by leptin though. In my research I've been led to believe that having LOW functional leptin (either through leptin resistance or actual low leptin) causes insulin resistance, and raising insulin lowers insulin resistance'

One would tend to think they develop in synergy, but I'm aware that there are some theories that leptin resistance occurs before insulin resistance.

OTOH, insulinogenesis causes leptin synthesis. Having had chronically high insulin is more or less a necessity for developing leptin resistance.

'That's also why fructose, which doesn't raise insulin, is so fattening. Glucose raises leptin and lowers insulin resistance'

That's true, fructose does not affect leptin in the same way as glucose. But this is hardly an issue in a non-retarded diet with whole foods. Unless you're drinking tons of soft drinks or eating refined shit daily you're in the safe zone.

'Lastly, I've always rolled my eyes at IF-ing. It's use in altering leptin, however, will keep my eyes wide-open from now on.'

I'm glad to hear it, Matt. Thanks.

Martin Berkhan said...


Yes, I missed a word (decrease). Corrected it. Modest refeed, well that depends.

Anon nr 2,

'Does that mean one would want to avoid BCAA supplementation during the fasted state due to the insulinogenic effect?'

Yes, unless it's taken before fasted training.

Read this

And this

Ryker said...


Thanks for answering my post. However, you said that insulin levels were "only" higher when compared to baseline. But wasn't baseline "normal" eating (e.g. no fasting). I namely thought that among the advantages of IF vs. such normal eating were lower insulin levels and better insulin sensitivity.

P.S.: I'm not trolling, I'm on IF, as well, but this seems to go against the grain of what I believed before.

Martin Berkhan said...


These results could partly be explained by the time the researchers took blood samples. Fasting venous samples were taken at 1:00-2:00 PM for measurement of serum levels of leptin,
insulin, glucose and lipids, and the time not change when Ramadan was initiated. Since a larger caloric load occurred in the evening vs baseline conditions it would also mean a later peak and drop in leptin and insulin vs baseline conditions.

Martin Berkhan said...

Another confounder is the calorie increase during Ramadan.

It would be interesting to do another study with a similar setup, but in this case

a) during equicaloric conditions

b) take fasting venous samples x hours after the last meal (x being constant for both conditions)

Wilmar said...

ah, so THAT's why you IF. great (and very important) post.

Anonymous said...

Thanks for sharing all this. Awesome post.

Anonymous said...

Interesting blog, motivating results! In your experience, how many refeed days a week is optimal, when the other days are hypocaloric lower carb days. I train whole body monday/thursday and these two days are refeed days, beeing high in carbs and calories. But are two enough?
The best

Martin Berkhan said...

Depends. Ask yourself how it's working first and foremost.

Marc said...

Martin, great post.

Are you able to shed some light on your 'modest' refeed. I'm interested as to how much over maintenance you'll shoot for, is it necessary to go over or is i just a case of basing most of the calories on carbs to influence leptin? My worry is going over may mess up the weeks deficit, leading you to spinning your wheels.

Nathaniel said...

Martin, I've read your blog from time to time but I've never commented before. I just want to say that this was an extremely helpful and informative post! Thank you!

Martin Berkhan said...


Thanks. A modest refeed is just that. Modest. The specifics depend on various factors; training volume, training frequency, subjective reaction to refeeds, leanness, among other things. I won't delve into how many grams of carbs you personally require, but needless to say, since you should be doing them fairly frequently (i.e 3x/week on training days), you need to keep them tempered if your goal is fat loss.

Martin Berkhan said...


Thanks, glad to hear you liked it.

nondual said...

Isn't every post-workout meal - with it's higher carb content, basically a little 'mini-refeed'? Heck, even a lower carb non-workout day has you bulking your calories in a sense and 're-feeding'.

Or am I completely confused as to what you were saying?

Martin Berkhan said...

Nope, you're right.

Marc said...

Cool, thanks for the heads up Martin, I've only been doing them once a week.. Hitting maintanence or very slightly above (not taking into account calories burned doing weights that day) Is it normal to look softer on the carb increase? Could be my mind playing tricks on me :-P

Martin Berkhan said...

Depends on the carb load and what you ate. Some would say they appear a bit softer after the meal. Others say they look fuller and more vascular. The composition of the meal and individual tolerance to certain food items are two large confounders.

Generally speaking though, it's not strange that you look a tad bloated, compared to the fasted state, after having eaten a big meal. But it's a trivial matter since it goes away over night or later in the evening.

Marc said...

Would cereals like cheerios affect this more than say pasta or rice? but I guess it is a pretty trivial matter.

Martin Berkhan said...

Hard to say, Marc. I've yet to conduct an extensive study on that matter. But given that cheerios are consumed with milk, and dairy products may cause bloating in some, that's something to consider. On the other hand, some people notice bloating/water retention from wheat products. Like I said, individual tolerance is a big confounder.

m said...

Hmm that's very interesting, never thought of the milk, wheat too. I suffer from IBS so 95% of the time don't eat any complex carbs (just fruit, yogurt, green veggies) but on the refeed I base it all on cereals really as that's my weakness. Also with the milk I only ever consume that with my cheerios. Might be onto something here...

Haley said...

I've spent the last several days reading through the information on your blog and all I have to say is "wow". You have so much information available! Great job and THANK YOU for sharing it! I got caught up in the 6 meals a day "stuff", and IF has really opened my eyes that it doesn't have to be that complicated. Thanks again!

Nathaniel said...

Martin, I'm trying to summarize the significance of all this stuff. This is what I got from it; please correct me if I'm wrong.

These studies seem to suggest that IF, combined with adequate re-feeds, may be a way to induce fat loss in the body while avoiding the drop in leptin levels that typically accompany fat loss. Therefore, possibly an effective way to manipulate the body's set-point?

And it appears that carbohydrate-containing re-feeds are effective in boosting leptin, while fat was not? They did not study protein, though? I would be curious to know if protein has a similar effect to carbs.

Am I understanding this stuff right? Thanks Martin.

Martin Berkhan said...


You're welcome.


'Therefore, possibly an effective way to manipulate the body's set-point?'

That's very speculative. Relatively speaking there's not much research on IF and leptin. The available research either shows that average leptin is unchanged but that the pattern changes into a peak and valley-pattern (in contrast to a more even pattern as seen w conventional meal patterns). Then there's some research showing more interesting and peculiar effects as mentioned in the article.

Protein has a lesser effect on leptin. Greatest impact in order: carbs, protein, fat.

Z said...

Great post! I just stumbled across your blog recently so forgive me if this has been done already but have you laid out a detailed diet phase anywhere that goes over how you structure the macros/refeeds with IF and exercise? Something like how UD2.0 is done? I would guess this would be something one would have to pay for but i would be really interested. Thanks!


Martin Berkhan said...

No, I haven't. That's for the book.

Anonymous said...

Great article. You consistently deliver good, thought-provoking and original material. Keep it up.

David Shores DC said...


Is it necessary for your clients to weigh and measure your food?



Martin Berkhan said...

Yes. They need to know how much they're eating one way or another. So do you if you want optimal progress.

David Shores DC said...

Thanks Martin.

That's what I was afraid of! LOL

I choose to measure.

Anonymous said...

Hey Martin,

I was just wondering if you ever struggled with loose skin. Then again, you weren't that fat in the first place, so it couldn't have been that big of a problem.

Martin Berkhan said...

I struggled with loose skin after my first few diets, but it tightened up as the years passed.

Moritz said...

very interesting read...

if you don't mind, i'd like to ask a question though:

do you know the reason why on some days you feel crappy in regard to mood, energy levels and focus while fasting, while others go just smoothly?

i personally can't see any reason, since my diet, workouts and sleep are just fine and those would have been my usual suspects haha

thanks in advance,


Martin Berkhan said...

Negative stress, procrastination or bordedom.

Matt said...

Your blog is the best fitness related read I had for a very long time. Awesome stuff!

I'm 20 years old, always been lean but rather scrawny. I've reached very low BF% in high school when I slightly cut the carbs (not consciously, I just ramped up the protein so I was constantly full) and started doing bodyweight exercises (handstand pushups are awesome!). At the time I had a clear cut six pack and visible veins on my abdominal wall even when fully relaxed. But I ended up slightly scrawnier than before, which wasn't my goal at all.

Now I'm somewhat loose with my diet, I eat 4-6 meals a day (fairly large ones). I only counted my cals once just to see where I was at on an average day and they were around the 3000 mark. Since I'd like to put on some muscle, before finding this blog I was about to start a classic bulk with a see-food diet (see food eat food), but now I might give IF a shot.

My height now is 179 cm and my weight is 67 kg. Here's a pic I took yesterday:
I never measured my BF% but it's definitely higher now than it ever was before.

I'd like to ask you something though. You mentioned that you and most of your clients used to be a little on the heavy side. What I want to know is, have you had any experience working with someone who is predominantly ecto and has little or no trouble keeping BF percentages low, but has a hard time gaining muscle? If so, how well does your approach to IF and cyclic calorie dieting work for them?

Sorry for the long comment.
Looking forward to more interesting stuff from you.

- Matt

Martin Berkhan said...


'What I want to know is, have you had any experience working with someone who is predominantly ecto and has little or no trouble keeping BF percentages low, but has a hard time gaining muscle? If so, how well does your approach to IF and cyclic calorie dieting work for them?'

It works very well if they can handle the food. If they can't, the problem is easily solved by including more easily digestable foods and liquids in the feeding window.

Chino said...

Hi Martin. The more I read about IF (specifically from your protocol) the more tempted I get to try it. I am very much anticipating the release of your book. I just read through your 'wrapping up 2007' post recently and I'd like to ask you a few questions.
1. At some point in time I became insulin resistant, this is when I packed on a lot of unwanted weight. I really like how IF does not try and avoid specific food groups, but I am worried about my insulin sensitivity, how will this and implementation of IF affect me?
2. What's a rough value that you set for your IF cut in terms of percentage?
I really see myself in you after reading your 2007 wrap up post except you started off heavy while I was actually the opposite where I was a stick all my life, so for some reason I just packed it and have worked hard since in getting where I am now (which resembles your 'The modeling days: age 19-22'). You have been an inspiration and want to take that next step in converting my 'now' to your 'now'. Thank you.

Martin Berkhan said...

1. Your insulin sensitivity will improve as you a) lose fat and b) embark on IF.

2. There's a reason I don't talk about specific macro percentages since a) it depends and b) I'm saving the nitty gritty details for the book. I've given rough outlines of how carbs, fat and protein is cycled in the interviews so go read them.

Thanks for the kind words.

Chino said...

Hi Martin, appreciate your response. I've got a rough idea but I'll reread the interviews. I'm just afraid of stepping into the IF world but I will. In the meantime, my last skinfold (professional) showed me at 6.9% bodyfat but the problem is that I was in a state of depletion due to long term SKD. I don't want to avoid food groups anymore and want to be relaxed as to stop the excessive cal/macronutrient counting, IF seems to be the perfect solution. Also, I'd like to be below 7% without being depleted. I'm currently fighting (a winning I might add) battle with my own demon, which is the monster appetite I have when I touch carbs. I've been on SKD for about 8 months with heavy training and have the occassional (every 2 months or so) refeed but a refeed keeping fat high to stay in ketosis. I've been relaxed about my diet in the past two weeks (another battle won against another demon of mine) by going back to CKD with a Sat/Sun carbup/refeed and I'm now should be roughly at 9-10% bodyfat which is ideally my non-depleted state. For the first time since returning to CKD I've been wanting to eat 'clean' foods, the past two refeeds I gorged myself but that was the tactic itself which worked and after the second one I actually stopped craving for crappy foods and started wanting to eat cleanly. So I'm slowly prepping myself up for IF. It was also 2 months of maintaining 7% bf that I started experiencing extreme cravings, something I've never gone through in the more disciplined dieting 8 months prior. Thanks again Marin, keep up the good work.

Anonymous said...

Hello Martin,

I'm thinking about the refeed days. Can I have 2 refeeds/week on my workout days and lower the calories the rest 5 days?

Example: losing fat 0,5kg/week= 2350kcal/day

5 days of 2000cal
2 days of 3350cal
Total cal of the week: 16700/7= intersection is 2385cal/day.

Will my diet take damage if I go such a low as 2000cal 5 times a week?

Thanks in advance.

Martin Berkhan said...

I don't know a thing about you, so I can't give you a definitive answer on that.

Anonymous said...

Thanks for your answer. I will just bug you one more time.

I'll reword it:

2 days of 500cal surplus of my maintance level(on training days on sunday and thursday)

5 days of -850cal cut of my maintance level(rest days)

That means monday, tuesday and wednesday all are restdays which mean 3 days in a row with -850cal cut of my maintance level each day intill my workout day on thursday, when I refeed.

Will such a big calorie cut -850 of my maintance level 3 days in a row harm my diet in any way before I refeed again on thursday? (monday,tuesday and wednesday)

I mean -850 cal cut of my maintance level is pretty big and doing that 3 days in a row before I refeed maybe isn't that optimal for keeping muscle and strength?

Or maybe it's better to have 3 refeed days/week, then it's only two days in a row with such a big calorie cut from my maintance level.

I hope I made it clear what I mean.

This would make everything clear for me.


Martin Berkhan said...

You still left out vital information, such as body fat percentage, so I can't give you a definitive answer. Nor is comments a place where I give out personal consultations or tell people how they should eat and train. I have clients for that.

That being said, your setup does not look bad and may work just fine.

Anonymous said...

Everybody seems to encourage us to eat 5-6 meals a day, but when I get hunger pangs I know this is the fasting time when my body is tapping into my fat stores, its as simple as that for me. You suggest that diet coke is OK during the fasting phase but I would amend this, despite the fact it is sugar free I have always found it still boosts insulin levels, and this has never helped me towards losing fat.

Martin Berkhan said...

'You suggest that diet coke is OK during the fasting phase but I would amend this, despite the fact it is sugar free I have always found it still boosts insulin levels, and this has never helped me towards losing fat.'

Bullshit. But I'm sure you believe yourself to be a special and unique little flower that get an insulin response from diet coke.

Despite all evidence pointing to the contrary.

Sonny said...

Martin, I've the same regards as Jon Fernandes posted on 3/17/10.

My goal currently is drop BF & retain strength in the gym.

Was wondering, if this approach is hazardous (not recommended).
1. Eat near psmf (RFL syle) on off days (rest or job).
2. Eat -500 calories from maintenance on training days.

Figure it might create deficit of 5500 = 1.5 lb a week.

Martin Berkhan said...

I wouldn't say it's "hazardous".

Leigh said...

Hi Martin,

Anxiously awaiting your book. I am especially interested in the potential to change the set point as I also was at my fattest as a teenager.

I am going to try IF with a protocol similar to Lyle's flexible approach.

I am curious about one thing: because of my schedule and desire to lose fat (currently at about 30%), I am running for 30 min in the morning and lifting or doing a crossfit workout in the evening. I am assuming that there is no need for the BCAAs in the morning? That would only be for lifting?

Also, does anything abut your protocol change for fatter people? (You and most of our clients seem to be going for single digit BF, I would be happy at 15%)

Martin Berkhan said...

I would recommend BCAAs before all types of anaerobic activity and long duration aerobic activity. Got an article coming up on that topic, so stay tuned for guidelines.

The basics don't change that much for higher body fat percentages. Depending on the individual I moderate the carb load post-workout and total carb amount on training days. Fatter = less carbs than leaner individuals.

Tarvo said...

Hi Martin,

I just started doing IF. What's a good way to find out my maintenance calories? I used to do a lot of cardio and according to the online calculators my maintenance should be 3500 calories. I have now dropped most of the cardio and I have no idea how many calories I should eat. My hunger is the same as before.

I'm around 15% bodyfat and want to drop lower and then start gaining (without gaining back the fat).

Anonymous said...

Hey Martin. Can you say something about IF and gaining lean mass?

There is much information about dieting with IF but I didn´t find anything about gaining mass.

John Cowell said...

Dear Martin,

I was wondering if you had any experience in implementing your system with endurance athletes? Is it possible to do or is it best to use IF to get the athlete to the desired body composition and then switch to a more "typical" protocol? Any input would be greatly appreciated.



John Cowell said...


I'm interested to hear your thoughts on how to implement IF with endurance athletes.



Anonymous said...

What a refeed of yours is like?

Anonymous said...

Hello Martin!

If you once have been fat in your life (I mean really fat). And then getting lean. Will that mean it's harder to put on more muscles, because you've once been fat? Meaning that when you're overeating again, the most of it will store as fat because you now have bigger/more fat cells from the times you were fat. This sounds like a myth to me and I just wonder if you have any proves about this?

I've been wondering about this for a long time and I want to be convinced about this "fact" from a proper source.

Would be really happy if you had any answers about this.

Thanks in advance!

Kenny said...

Hi Martin,

I just learned about IF yesterday and I would like to say that I've learned alot from the blogs and topics.. Thank you! I plan to start next Monday I need to food shop lol there a specific type of scale you use to weigh ?

Anonymous said...

in one of your posts you said no bcaa in the fasted state unless its before training. What is the reason for this? Wouldnt bcaa help preserve muscle?

Anonymous said...

From what I understand, leptin resistance isn't just a compensatory mechanism for increased leptin in circulation but can be induced directly by excessive fructose consumption. Additionally, systemic inflammation can also cause noise/desensitization at the leptin receptor, namely in the hypothalamus where it regulates bodyweight, the magic "set point", satiety/appetite and metabolism. Chronic excess overeating of foods that stimulate leptin (refined carbs stimulate most leptin release per cal) and foods that cause systemic inflammation i.e. oxidized veggie oils (PUFA's), low protein diets, will lead to weight gain and leptin resistance, fueling more weight gain and leptin resistance etc.

I believe in IF but this is also why a Paleo diet seems to work fine for obese people, it gets rid of inflammatory foods such as refined carbs/veggie oils/high fructose and adds quality fats/vegs to the diet. IF + weightlifting to boost muscle/bone/ that's the real fucking deal, Martin.

Byron Richards is a pretty knowledgeable clinical nutritionist on leptin. he has online talks + several books on leptin and its practicality

Anonymous said...


Do you have a book out? If not, you should write one.

Gene said...

Question to the group, I have been on the IF diet about 2 weeks now, took a little while. How are you structuring your meals during the feeding period.

My routine is to workout at 600 am, start eating at 12 until about 8pm.

Are you still eating 1-2g protein per lb of wt and such each day? Are you eating just 3 meals or more. I find it hard to get all my calories and ~300g protein from only three meals a day. What are you doing?


Gene said...

Question to anyone, I have been on the IF diet about 2 weeks now, took a little while. Wondering how are you structuring your meals during the feeding period?

My routine is to workout at 600 am, start eating at 12 until about 8pm.

Are you still eating 1-2g protein per lb of wt and such? Are you eating just 3 meals or more. I find it hard to get all my cals and ~300g of protein from only three meals a day.


Anonymous said...

I seen this in a 2009 study I was reading at and remembered this post and support your belief that weight shouldn't be lost quickly.

"It appears, therefore, that leptin-responsive neurons implement rather complex mechanisms of controlling their own sensitivity to leptin. But what is the physiological and evolutionary function of this? Interestingly it has been suggested that leptin resistance may be a mechanism of helping to detect energy flux (the rate of energy expenditure) rather than the current energy stores alone. The determination of energy flux is a more accurate indicator of the true energy balance and the future energy requirements of an organism. For example an organism may still be in negative energy balance despite having high energy/fat stores during pregnancy, illness, or intensive exercise. A system which dampens leptin responses in high energy states is more sensitive to negative energy flux as it is less likely to be potentially disastrously overwhelmed by strong anorexic signals."

review on customized fat loss said...

wow those are really crazy transformations. But i noticed you have a REALLY low body fat percentages throughout, which is key to looking good! (although having decent muscle mass is good too)

Herman said...

Hi Martin,
Can you help me? After eating a high protein meal from breaking the fast- I am feeling tired, hot, and have a lost of energy.

Thank you,

Chrismagic said...

Thoughts on this study?

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