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The Full Diet Break

Among others idea that I “formalized” in my Guide to Flexible Dieting was the idea of taking a break of 7-14 days during a diet where calories were brought to maintenance.   I didn’t invent the idea by any stretch, Dan Duchaine had been advocating that a decade before me.  But I like to think that I brought the idea to the mainstream.  That is an idea I call the full diet break.

What is A Full Diet Break?

Whenever I bring up this topic, I tend to get sort of confused looks from people.  What do you mean I’m supposed to take a break from my diet?

As I opined on the podcast, I have no idea if this is just an idea endemic to America (where we suffer from a long-history of a Puritan work ethic) or is just common to dieters but most people who are trying to lose weight or fat seem to feel that the key to success is to be as miserable as possible for as long as possible. While this certainly isn’t the only reason diets fail, I don’t think it helps.

This was actually a big part of the reason that I originally wrote A Guide to Flexible Dieting as there is a good bit of research (comparing rigid and flexible dieters) showing that people who are more flexible in their eating patterns are more successful in the long-term, showing less binge eating habits and weighing less.

And while that idea might seem contradictory given the other book I mentioned The Rapid Fat Loss Handbook, I’d only note that that book incorporates many of the flexible dieting principles anyhow.  But I’m getting off topic.

The idea of a full diet break, in short, is that it’s a period, typically 10-14 days where explicit dieting is stopped.    During this time, calories should be raised to roughly the estimated maintenance level although I typically like to adjust this downwards by about 5-10%.  Carbohydrates should be a minimum of 120-150 grams per day and training volume can be increased during this time as described here.

As I said above, I’m far from the first to recommend this. The first formal suggestion I remember of this came from an early mentor of mine, Dan Duchaine.  He routinely recommended 2 week periods at maintenance between periods of active contest dieting for a variety of reasons.  I’m sure others did as well.

Interestingly, research has finally caught up to both he and I, showing that this approach can help to avoid some of the metabolic adaptation that occurs while dieting.

I simply formalized the idea after reading a fascinating little paper on the topic.   This is what I wrote in A Guide to Flexible Dieting:

Before I continue, I want to tell you about one of the coolest studies I’ve seen in a while. I say cool mainly because of the fact that the scientists failed so miserably in their goal, while making an absolutely wonderful discovery.

For anybody who wants to look it up, the full reference is “Wing RR and RW Jeffrey. Prescribed ‘Breaks’ as a means to disrupt weight control efforts. Obes Res (2003) 11: 287-291.”

The study was set up to find out why people go off the dieting bandwagon. That is, the researchers wanted to determine what behavioral things happen when people go off of their diet for some period, and why they have trouble going back on.

So the subjects were first put on a typical diet meant to cause weight loss. Then the subjects were told to go off the diet for either 2 weeks or 6 weeks so that the researchers could see what happened when people fell off their diet but hard and started regaining weight.

Here’s what happened: not only did the subjects not regain very much weight, but they had almost no trouble going right back onto their diet when the 2 (or 6) weeks was over. So the scientists completely and utterly failed to reach their goal of studying what they wanted to study.

Basically, they made an almost accidental discovery which raised another set of questions:why didn’t the subjects regain a ton of weight and why did they have little problem returning to their diet?

That is, knowing that most people who go off of a diet for even a short period will balloon up, regaining weight rapidly, and fall off their diet, what made this study (or these subjects) different?

The basic issue seemed to come down to that of control. To understand this, let’s consider two different situations. First let’s say that you’re the typical rigid dieter hammering away on your perfect diet, no lapses, no mistakes. Suddenly something comes up that is out of your control.

A stressful period of life, the aforementioned vacation, whatever. Feeling out of control, you figure your diet is blown and the binge begins. Does this sound familiar at all?

But consider what happened in this study, the subjects were told by the researchers to go off their diet; in essence, the break was part of the diet. And they didn’t blow up, didn’t gain a ton of weight, and had no problem going right back onto the diet.

I suspect that that was the key difference and why the study failed so miserably: control.  Psychologically, feeling like the break is now under your control, or that it’s part of your overall plan, makes it far easier to not feel like the diet is completely blown and get back on the diet when things settle down.

Do you understand what I’m getting at?  Tangentially, and this is discussed in the book, while many seem to flexibly diet sort of intuitively, many don’t seem able to do this.  For them I recommend what I confusingly call structured flexible dieting.

Basically, planning the timing of the strategies described in the book.  Basically, it puts the dieter in control of the diet, rather than the diet controlling the dieter.  Which is what I think a big part of the study described above was about.

So that’s what a full diet break is, the next topic to address is what the purpose is.

There are actually a number of good reasons to take a full diet break, both behavioral and physiological.  I want to look at both.

Physiological Reasons for The Full Diet Break

The physiological stuff is the stuff I talk about all the time here on the site, on the forum and elsewhere.  When folks diet and lose weight/fat, the body adjusts metabolic rate downwards.

While a majority of this is simply due to weighing less (smaller bodies burn fewer calories), there is also an adaptive component, a greater decrease in metabolic rate than would be predicted due to changes in things like leptin, insulin, thyroid hormones, etc.

By moving to roughly maintenance for a couple of weeks, many of those hormones are given time to recover.  Thyroid hormones come back up, as does leptin.  This is a big part of the reason for the recommendation to raise carbs to 100-150 grams per day as a minimum.

Thyroid hormones are distinctly sensitive to carbohydrate intake as are leptin levels (especially in the short-term).  Just raising calories but keeping the diet very low carb doesn’t accomplish everything hormonally I want the full diet break to do.

This is also the rationale behind the duration, thyroid hormones and the effects that they exert aren’t immediate.  It may take 7 days of eating at maintenance for thyroid levels to come back to normal, but you need at least another week to get many of their effects to max out.

So in answer to the question “Can I make the break shorter?”, the answer is “No.”  I know that everyone wants to GET LEAN NOW but unless you are a contest dieting bodybuilder or figure chick and there’s no real-time constraint, what’s the hurry?

There are other effects as well.  Hormones like testosterone often go down during dieting and female hormones can be whacked out too.  Cortisol generally goes up when you diet and raising calories and carbs helps shut that off for a bit.

I’d note in this regards that many find that, after a period of hard dieting, they often keep leaning out into the first week of a planned break.   As I discussed in the article Of Whooshes and Squishy Fat, some of it may simply be dropping water.

But some of it does seem to be true fat loss.  People keep bugging me for the mechanism and my current best-answer is “Magic!”.  At some point, I might throw out some of my theories on it.  Not today.

As well, for leaner individuals, even if they do everything ‘right’, there is often a loss of performance or muscle mass during a diet.  The two weeks with raised calories gives them the capacity to train a bit more and recover what they’ve lost before moving into the next stage of dieting.

Finally, the idea has been thrown out there that stabilizing at a given (reduced) body weight or body fat might give the body a better chance of accepting that new weight as “normal” and adjusting setpoint.  Frankly, I’ve never seen anything to support that in the literature.  It’d be lovely but I tend to doubt that’s how it works.  I’m just mentioning it for completeness.

As I mentioned above, recent research has shown that alternating periods of dieting with 2 week diet breaks helps to reduce the metabolic slowdown that would otherwise occur.   Such approaches may have other benefits for athletes as well.

Psychological Reasons for The Full Diet Break

There aren’t only physiological reasons for using the full diet break concept.  For many dieters (especially heavier, since the adaptation issues tend to be less) the benefits may be as much psychological or behavioral as anything else.

Frankly, this is something that I feel that many lean diet/obesity experts often can’t really comprehend, the types of psychological stress that dieting can engender for people with a lot of weight to lose.

Tangentially, since I’m just in that kind of mood, I see the same thing in a lot of the popular “Do body weight metabolic training to lose fat” manuals.  The exercise are always demonstrated by skinny fit people.  I want to see some of these coaches have an unfit individual at 300 pounds do a t-push up on 1-arm.  But I’m really off-topic now.  Training the obese beginner is its own topic.

Anyhow, say that you are someone who is extremely overweight, perhaps you have 50-100 pound of weight to lose (or more).  Going by the standard recommendations of 1-2 pounds per week, that means that you are realistically looking at 25-50 weeks of dieting.  And let’s face it, no matter what diet you are on, that means some period of feeling hungry, deprived, etc.  There’s just no getting around it.

For people with more weight to lose, the time frames may even be extended beyond that.

Now, I want everyone to stop and think about that for a second, the amount of mental stress that that tends to create from the get-go.  Is it any wonder that some people never bother starting?

Breaking Long Dieting Periods Into Manageable Chunks

Put differently, if I told you that you had to be miserable and feel deprived and hungry for the next 1-2 years, would you bother?  Probably not.

But what if, instead of facing that huge mountain, you knew that you only had to go say, 10-12 weeks of dieting before getting a break for 2 weeks where you could eat relatively “normally” (note: this does NOT mean returning to your old eating habits) before starting the next phase of active weight loss?

Suddenly, that might seem a whole hell of a lot more doable.  And if you’re using the other concepts of free meals (relatively ‘normal’ non-diet meals eaten once or twice a week) and refeeds (periods of deliberate high-carbohydrate overfeeding) during the periods of active dieting, it may be that you’re never having to feel like you’re full-blown dieting for more than 4-5 days before you get a small break.

Recent diet approaches such as Intermittent Caloric Restriction (ICR) take this very approach, alternating hard dieting days with days of normal eating.  Even if they are no more effective than regular calorie restriction for fat loss, for many they may be more effective in terms of adherence.

Does that make sense?  We’ve moved from “You have to be hungry and miserable for the next 365 days straight” to “You will get a break of some sort from your diet at least once a week and perhaps more.”

Let me put this in a slightly different context: it would be a rare coach indeed who would expect their athletes to work at 100% 7 days/week, 4 weeks a month, 12 months a year.  Athletes have light days, perhaps one day off per week, perhaps every 4th week with reduced loading, they usually take 2 weeks completely off every year.  Sure, some of this is to allow physiological adaptation but some of it is psychological; you can’t maintain that intensity every day of your life without burning out.

Why should a dieter expect (or be expected) to do exactly that?

Anyhow, those are some of the psychological benefits behind the full-diet break. For people with extended periods of dieting ahead of them, in addition to any other benefits, it breaks the periods of active dieting into much more manageable chunks.

Instead of expecting these seemingly never-ending periods of extended dieting, there is at least some light at the end of the tunnel. That’s in addition to putting the control of when the breaks happen rather than having the person lose control because the break is forced upon them, they can plan it themselves.

On that note, one topic I go into in a bit of detail in A Guide to Flexible Dieting is whether the full break should be planned or unplanned.  In that context, one of the more powerful uses of the full diet break is that it can be used in situations (such as the holidays, or vacation) when someone knows that they won’t be able to really stick to their diet.

In those sorts of uncontrolled situations, I find that people tend to feel a real sense of loss of control and they can go off their diet never to return. The full diet break can simply be planned around those time periods and suddenly the control has been returned to the dieter.  They can do their best damage control knowing that, if anything, the 10-14 day period (or whatever) is finite and won’t do that much damage, returning to their diet when it’s over.

Summarizing The Full Diet Break

So that’s the basics of the full diet break. Of course there is more to it discussed in the book but I’m running long-again.  How often to take a break is a big issue and fundamentally depends on the person’s body fat.  Contrary to what most think, leaner individuals should take diet breaks MORE often than fatter because the adaptive aspects of dieting are greater.

Proving once again that I’m just retreading others who came before me, Dan Duchaine recommended 4 weeks of dieting before 2 weeks of raised calories and then 4 more weeks of dieting as part of a 10 week contest diet.  I’m a bit more flexible (get it) than that and I base the duration of the diet on initial body fat percentage.  Leaner individual might go 4-6 weeks before taking a full diet break, someone who is carrying more fat might go 12-16 weeks before they need or take a diet break.  Folks in the middle go somewhere in-between.

I’d note that I even think that contest dieters should use full diet breaks although this requires not only being lean enough when they start but also giving themselves sufficient time to include the break AND still have time to get lean enough.  Most dieters start too late and end up not being able to take a diet break but I believe that their diets would work better if they did.

Of course, there’s more information than this that I don’t have time to cover.  It’s all in the book and I’d only finish by saying that I wish more people would take full diet breaks.  It’s a concept that tends to be counterintuitive (how does going off a diet make it work better) but in my experience and with what the research says, it works.

People tend to fixate on short-term results (as noted above they want to BE LEAN NOW) but for most applications, long-term adherence is far more important.  In the big scheme of things, what is two weeks not losing fat if, not only does the break mean you lose fat MORE effectively (because you’ve normalized hormones) but you increase your odds of long-term success by not being so psychologically stressed all the time.

That’s what the full diet break is all about.

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22 thoughts on “The Full Diet Break

  1. Hey Lyle,
    What would your exercise recommendations be for someone during the full diet break? Should exercise increase, decrease, or stay the same? Is there a way to maximize the physiological benefits that are occurring due to the full diet break through exercise?

    I know that I would have to give my “permission” to my more compulsive dieting clients to exercise more to “make up” for the increase in calories, to even convince them to take the diet break.


  2. I really believe you are the most tuned in author regarding health and weight loss. You always leave me something important to ponder. I am grinding through a diet and the way you present your case makes real sense. Thank you.

  3. Lj: it would depend on what they were doing beforehand. For example, say they were an athlete leaning out who was training pretty close to the edge of what they should be for dieting. I might make the full diet break coincide with a deload for maximal recovery.

    But if someone were coming off of a very low volume of training (e.g. what’s in my rapid fat loss handbook), I would probably tend to increase volume/frequency. Some of it for damage control (give the extra calories somewhere to ‘go’), some of it for psychological reasons.

    In other contexts, I might keep training unchanged.

    What should NOT happen is that the increase in calories is fully compensated by an increase in activity. So they can’t add 500 cal/day and increase activity by 500 cal/day. becuse then the physiological functions are not met as they are still technically in a net energy deficit (to do any fixing of hormones or metabolic rate requires net caloric maintenance, that is intake = output.)

    Hope that makes sense.

    Mike: thanks.

  4. Lyle,

    You mentioned a study where people were underfed for 4 weeks before overfeeding for a week and still losing weight. Might you have that study around?


  5. Lyle
    What you mention here seems to have similarities with the ABCDE stratagy. I forget what the letters mean but it involves dieting for two weeks then eating well for 2 weeks.

    The idea is that when you begin to consume more food than required for maintainance the excess food is stored as glycogen muscle and fat. At first the dominant process is glycogen storage then muscle growth but by around 2 weeks that is more or less done and the dominant process is fat storage.

    The diet period is to reduce any fat stored and to create a hormonal environment for the body to respond to the overfeeding period. does this make sense?

    Thanks for another interesting post


  6. Martin: No. ABDCE was a staggeringly flawed concept that made people fat and weak and has pretty much nothing to do with what I’m talking about.

  7. Am J Clin Nutr. 1999 Sep;70(3):321-30.Click here to read Links

    Comment in:
    Am J Clin Nutr. 1999 Sep;70(3):305-6.

    Effect of prolonged moderate and severe energy restriction and refeeding on plasma leptin concentrations in obese women.
    Wisse BE, Campfield LA, Marliss EB, Morais JA, Tenenbaum R, Gougeon R.

    McGill Nutrition and Food Science Centre, Royal Victoria Hospital, Montréal, Canada.

    BACKGROUND: Plasma leptin in humans is subject to both long- and short-term regulation; it correlates with indexes of body fat that can only change slowly. However, short-term fasting causes large and rapid decreases. OBJECTIVE: We tested the interactions between energy intake and fat loss on plasma leptin during prolonged moderate and severe energy restriction, with a view to understanding mechanisms of control. DESIGN: Postabsorptive leptin was measured with an enzyme-linked immunosorbent assay specific for the human peptide in 21 obese women aged 41 +/- 3 y (weight: 102 +/- 4 kg; 48 +/- 1% body fat) after 1 wk of a weight-maintaining diet and then weekly for 4 wk during a total fast (group 1); a 1.9-MJ/d all-protein, very-low-energy diet (VLED) (group 2); or a low-energy, balanced-deficit diet (BDD) providing 50% of maintenance energy (group 3). In groups 1 and 2, leptin was also measured after 1 wk of refeeding with a diet equivalent to the BDD. RESULTS: Mean leptin decreased markedly by up to 66% (P < 0.001) at week 1 of energy restriction and then gradually thereafter. The change in leptin per kilogram fat mass correlated with that in glucose concentrations [r = 0.538 (P = 0.012) at week 1 and r = 0.447 (P = 0.042) at week 4] but not with that in fat mass. During refeeding postfasting, leptin increased (P = 0.008), despite an ongoing loss of fat mass and correlated positively with changes in resting energy expenditure. At times with comparable cumulative energy restriction and fat loss between diets, the percentage change in leptin paralleled that in glucose. CONCLUSIONS: In obesity, changes in energy intake over days to weeks are a primary modulator of plasma leptin concentrations that are related to the change in glycemia and are able to override the regulatory influence of fat mass.

  8. Thanks for this article. I stumbled on this approach some time ago and have been able to lose almost 50 pounds by taking breaks when I feel I need it. Nice to see that there is science to back up my (somewhat accidental) success.

    I wish more people who have many pounds to lose could have this information. It is truly overwhelming to lose large amounts of weight, and your approach is so sensible and accessible. I’m becoming a personal trainer myself and I will definitely guide folks to your material.

    Thanks again.

  9. Lyle,

    The following question is somewhat related to a conversation I was recently having with a neighbor of mine. He’s a devoted gym rat, but a few months ago he sustained back injuries when a car blindsided him on the road. During the early phase of recovery he kept calories up to help with the whole process, however as the months went on, he began to steadily reduce intake because he wanted to keep his bodyfat levels in check. Currently his daily intake is rather low for a male, but he is also not currently engaged in any notable physical activity yet.

    He commented on feeling like his testosterone was in the toilet and how he was feeling a high level of mental stress lately. So my question is this…..while caloric restriction is likely no aid in such cases, is it possible that the high level of mental stress could be the main culprit behind how he is feeling as opposed to the caloric restriction?

    Initially I though it might be the current restrictive intake, but he’s been at this level for a few months, and he says that feeling like someone shut off the testosterone coincided with the things that were mental triggers for episodes of stress. And while his intake is below 2000 kcal/day the nutrient density of what he does consume is quite high.

  10. Jack: Both are involved. Stress in general can do nasty things to hormones but caloric restriction doesn’t help. Nor does the body heal well in a deficit. If he’s returning from an injury, he shouldn’t be dieting in the first place.

  11. Lyle,

    Would a moderate increase in caloric intake via fat and protein be effective in restoring normal hormone levels or are carbohydrates necessary?


  12. Lyle,

    Sorry – saw you answered the question already in the article.


  13. I ran straight through. See a few people who succeed with breaks, but a lot more who it throws them off stride. Better for the vast majority to rock on program. Through aniversieries, holidays, travel, etc. (There are simply too many “excuses” for any to be special…and yes I include funerals and alien landings in there…and dates and any of that crap). Oh…and no booze either. It’s just mentally easier to rock at 100% and not have to go on/off of the groove.

  14. And once you settle into being on program it is not “miserable”. It is habitual.

  15. Some thing people who have never suffered from overeating issues can’t seem to grasp is telling a person with a food addiction that they can have free days or telling them to take a break from their diet is like telling a cocaine addict trying to get sober that they can have all the coke they want on Sundays or to help them stay sober to go on a week long bender. How does that make any sense? If you have eating issues there are some foods you should never eat again because they are trigger foods and people who are serious about losing weight need to accept this. I think weight loss programs who say you never have to give up what you love do this to hook people in because people don’t want to be told they can never have a cheeseburger again or a slice of pizza and they will avoid those programs. People need to learn to love healthy food instead of creating programs that promise a cheeseburger for all their hard work eating all those yucky vegetables.

  16. In moderation, why is a cheeseburger or slice of pizza ‘unhealthy’? If I use low fat cheese and 4% beef, why is a cheeseburger bad for me? What if I use lower fat cheese on a boboli shell with chicken breast and veggies? Is that unhealthy? Sounds like you’re projecting a bit with this one. Perhaps you can’t control your eating and you think everyone should be like you.

    That said, in a Guide to Flexible Dieting, I talk about the issue of trigger foods.

  17. Lyle,

    I love the idea of diet breaks. All the points you made in your article have been spot on for me. As for the analogy of telling a cocaine addict to binge to help with their habit makes no sense whatsoever!

    I personally love staying strict on my diet and then rewarding myself (within reason) with a break. As previously mentioned, you are in control of the diet, not the other way around as is often the case.

    Preach on Lyle, preach on.

    Forever a fan,


  18. Just a comment on the study mentioned in the article:

    I agree with the control aspect, and that dieting in “smaller chunks” can be more effective. I think that accountability could be playing a role here too. If the participants knew that they were going to be measured after the break, they may have been less likely to binge.

    I love my chocolate and manage to incorporate it into my diet – as long as I don’t go over my macro-nutrient targets. And if I sometimes go over a bit, it’s not the end of the world.

  19. I read this article 2 months ago, shortly after restarting my long-stalled diet, and decided to schedule in a diet break. I lost 25 pounds in 3 months, and now I’m one week in to a two-week break. My body feels like it’s on vacation, and looking forward to the break helped me stay on track during moments of weakness!

    I still have the food diary I kept during my first run at the diet. It spans a 16-month period during which I managed to lose 60 pounds — 42 lbs in the first 5 months; a mere 18 lbs in the following year. As I look back at the old data, it’s clear that my body was desperate for a break, but I still tried to trudge on…
    – The 10th week was my first bad week, but appears to be “just an exception”
    – By the 15th week, diet velocity was reduced for good
    – Weeks 23 and 24 were actually a slight calorie surplus. I was still trying to diet, but was losing the will.

    Things got progressively worse after that, until I gave up entirely. This time around, with regularly scheduled breaks, I’m hoping to finish the job!

    I really appreciate your no-bullshit and primary-literature-driven approaches to diet and exercise, Lyle. Thanks so much for putting all this excellent info on the web!

  20. I thought it might interest you to know that I have been able to maintain something very close to an ideal body weight with a full diet break once a week. I eat what I want, no restrictions, and the following day return to the low carb, low fat, low calorie diet that keeps me lean and healthy. Works for me! BTW, I continue to exercise on my days off the diet…

  21. Fantastic… Psychological and hormonal aspects of dieting are so overlooked. I will be little exagerating now (iam not on ketogenic more like zone diet with well enough carbs) but i often feel a bit letargic, grumpy, anxious, agressive, zoned out (hormonal) and my mind is playing all sorts of tricks on me to get back to tasty comfort food (psychological). After 2 weeks on calorie counting diet i feel like iam some kind of weird, nerd, alien worm reading all nutrition labels, measuring every food and feeling stressed and generally deprived of joys of life (food) with low sex drive among all the happy people around me giving jack sh#t about their extra kilos eating chocolate filled croissants, drinking creamy Starbucks capuccinos and enjoying italian pasta and cakes… just having a good time generally 🙂 its really psychologically terror on some days trying to convince yourself you are actually doing good for yourself with the grey diet glasses on and many miles to go ahead…

    Also i giggled when you exactly mentioned my frequent mental image when i see some excercise videos of lean athletic people trying to sell excercise programs or TV marketing plastic gizmos to overweight people who can barelly crawl down their TV couch… the idea of them doing burpees is hilarious and very sad at the same time…

  22. Sharon, I hear you. I know people like this and am one myself. Lyle, I don’t think she was implying everyone should be like her or food addictive people. But for people with over-eating disorders from addictive natures, I think it’s a slightly different situation.

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