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The Long Term Delayed Fat Loss Effect

Over the many years I’ve been involved in the fat loss game, I’ve seen some weird stuff happen.  When I was in my 20’s and only thought I knew what I was talking about (as opposed to now when I’m simply usually sure I do), I had observed one of the things I’m going to talk about today but didn’t have any real clue why it happened.  With clients or whatever, the only answer I could give was “Because it does.” or “Magic!”.

Now, I have a bit more clue what’s going on, or at least what I think is going on so I’m going to share one of these with you (I’ll address others in future articles).  Today I want to talk about something that I like to call the LTDFLE,  an acronym that I genuinely hope you will use at every possible chance on forums to confuse people, and which will make sense shortly.

The Long-Term Delayed Fat Loss Effect (LTDFLE)

.Anyone who has had the headache-inducing misfortune of reading (or trying to read) Supertraining by Mel Siff and Yuri Verkoshansky may have a clue where I’m going with this section heading.

In that book, one topic that is discussed rather endlessly is the long-term delayed training effect (LTDTE), a phenomenon whereby strength/performance gains often show up considerably (e.g. 2-4 weeks) after the heavy training has been done.  This can actually be explained fairly simply through a two-model fitness/fatigue theory of adaptation but I’m getting way off track.

LTDFLE stands for Long-Term Delayed Fat Loss Effect (I’d note that I have also seen a LTDGE which is a Long-Term Delayed Growth Effect but that’s another topic for another article).

Basically, this is the phenomenon whereby fat loss continues to occur even after the diet has been ended and/or calories have been raised back towards/to maintenance or even above.

In the same way that fitness sometimes continues to increase after the period of heavy loading, it’s almost as if there is some type of fat loss inertia whereby the diet continues working even after the person ends it.

Now I’ve talked about the phenomenon of whooshes before, a situation where folks will stall on their diet and then, overnight, lose several pounds of weight. But that’s more of an acute thing that I think can clearly be related to water retention/the release of such that happens when people break their diets (deliberately or otherwise).

The LTDFLE is a bit different and can last from 4-7 days (on average).  During that time, and note that this only happens after fairly prolonged dieting, as calories are brought up, people continue to get visibly and measurably leaner.  Skinfolds continue to drop, other measurements will continue to change in the direction of a decreased body fat.

I’ve observed the LTDFLE in myself, in trainees/clients and it’s something that a lot of bodybuilders (depending on how nuts they go) experience in the first few days after a show.  After all that work, after all that effort, they end up looking their best 2-3 days after the post-contest binge has started.

In fact, there’s actually even a weird study from back in the late-90’s that saw this although the researchers had no clue what was actually going on (because nutrition researchers don’t read enough basic science/endocrinology).

In it, folks were dieted hard for 4 weeks and then progressively refed (raising calories over the 5th week towards maintenance).  Body weight kept going down in Week 5 despite the gradually increasing calories (as I recall, they didn’t measure body composition).

What Explains the LTDFLE?

Now, it seems fairly obvious that at least some of the LTDFLE is due to water retention and water balances, just as is the case with the short-term whooshes that can occur.

Although there is a great deal of variance, people often retain water (both under the skin and possibly within fat cells) when they are dieting hard and restricting calories and much of this is related to increases in the hormone cortisol (please note that water retention is profoundly more complicated than this).

Raising calories/carbohydrates and/or reducing training tends to shut down cortisol release.    Suddenly the body stops freaking out and water is dropped.  But I wouldn’t expect water loss to explain a full week of visual changes.  A day, maybe two, sure.  But not the 4-7 days that the LTDFLE typically runs.

An additional factor that is certainly involved, and especially with folks on low-carbohydrate diets who are doing a lot of training, is replenishing muscle glycogen.  As carbs are raised, the body starts sucking up carbs (this has an additional effect of pulling water into muscle which probably also accounts for water shifts), they fill out and start to look better.

This is assuredly a big part of why bodybuilders often look better 2 days after their show; instead of looking stringy and flat on stage, they get full and pumped.

If water is being dropped from the body at the same time, all the better from a visible standpoint.  Please note that muscle glycogen is only increased if the caloric increase comes from carbohydrates.  Pigging out on high-fat fare won’t get it done.

Of course, the increase in glycogen/water mediated lean body mass.  In premise this will lower bodyfat percentage but the effect will be miniscule.  It all helps of course but this small effect can’t begin to explain it.

But even with that, it does seem that actual fat is still being lost, skinfolds get measurably smaller and people look leaner (and depending on what’s done next.  Often the skinfolds stay down suggesting that it’s more than just a transient water shift magic trick).


So beyond the above explanations, what’s really going on?   I suspect that at least some of it is related to the hormone leptin and all of the effects it has on bodyweight regulation.  As I’ve discussed in various books as well as when discussing the full diet break, leptin levels increase fairly rapidly when carbohydrates are increased.  Even 5 hours of over-feeding carbs can raise leptin.

With even a few days of eating more calories/carbs, leptin will go up.  And while many of the effects of leptin aren’t immediate (which is part of why I recommend 10-14 days for a full diet break), some of them might be.  Leptin is part of what regulates cortisol levels for example (leptin inhibits cortisol release) so at the very least, increasing leptin would help to reduce water retention.

But some work has also shown a direct effect of leptin on fat cells in terms of lipolysis. Leptin also promotes fat oxidation in skeletal muscle and elsewhere, perhaps the increase in leptin is directly stimulating actual fat loss.  Of course, that explanation is predicated on leptin going up/having a greater impact on things than the excess of calories coming in has on fat gain.

Related to that are thyroid hormone kinetics.  On a diet, conversion of the relatively inactive T4 to the more active T3 goes down in the liver and this rebounds fairly quickly when calories (and especially carbohydrates) are raised.

This is why I recommend a minimum of 100-150 grams of carbohydrates per day when people take a diet break.  That’s how many carbohydrates it takes to normalize the conversion of T4 to T3 in the liver.  Improving T3 levels will also help to renormalize metabolic rate.  As well, leptin is involved in the control of thyroid stimulating hormone (TSH) so increasing leptin may also be driving thyroid output.

Now, T3 has both short-term and long-term effects on metabolism with most of the long-term effects being related to changes in gene expression; those take time to maximally occur (at least 14 days).  But T3 can also be degraded to T2 which has immediate metabolic effects on energy expenditure and it seems possible that increases in T3 and subsequent breakdown to T2 might be raising metabolic rate enough to not only offset the increased calories but also to generate extra fat loss.  That might explain part of the LTDFLE as well.

Other Delayed Effects

I mentioned gene expression above, this is just a nerd term referring to changes in which genes are turned “on”or “off” (simplistically speaking) in various cells.  And gene expression changes in response to dieting, caloric intake, activity, etc.

While some changes happen pretty quickly others take longer. It’s not an instantaneous process.  Many have observed that often a diet takes a solid week or so to start “working” and this may be related to slower changes in gene expression when someone moves from an above maintenance caloric intake to a below maintenance caloric intake.

And the same may be working in reverse, the body is still effectively in a “fat burning mode” for some period of time after calories are raised.  Along with any direct effects of leptin and/or thyroid on lipolysis/fat oxidation/metabolic rate and the shifts in water balance, the situation is still simply this: people often keep getting leaner in the first week off their diet (again, this assumes that they don’t go totally nuts with food intake).

I’d note in this regards that my own Ultimate Diet 2.0 actually takes advantage of this to get a short-term sidestep of the energy balance equation: for about 24 hours following the 4 hard days of dieting/glycogen depletion, even in the face of massive carbohydrate intake, the body preferentially stores the incoming carbs as glycogen while using fatty acids for fuel (part of why fat intake has to be kept low during the carb-load).  Folks may be at literally double maintenance caloric intake and still be losing fat.  Magic?  No, just good science.  And maybe a little magic.

Summing Up the LTDFLE

.And that’s the oddity that is the LTDFLE: that magic period where, despite raising calories, you keep leaning out and losing fat.  It’s only about 7 days at the longest and can be shorter if people go really nuts with their food intake.

This is especially true if a lot of high-fat foods are consumed for extended periods.  Empirically, making the LTDFLE work the best seems to involve raising carbohydrate intake moreso than dietary fat.  In that vein, in the short-term (2-3 days), leptin levels are only responsive to increasing dietary carbohydrate intake, not fat.

So that’s the LTDFLE, an oddity of fat loss that tends to occur after fairly prolonged dieting when calories are raised.  It’s not universal and doesn’t always happen but when it does, enjoy it.

Before I finish, let me make one thing very clear which is that the LTDFLE only occurs after fairly prolonged actual dieting (which can still contain free meals and refeeds as discussed in A Guide to Flexible Dieting).  Don’t think that you’re going to get the magic effect of the LTDFLE by half-assing it for a couple of weeks and then raising calories and voila.

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16 thoughts on “The Long Term Delayed Fat Loss Effect

  1. cool article Lyle. I always liked you hypothetical/theoretical stuff the best.

  2. I’m a little curious what would happen if one was to do a low calorie day followed by a high calorie day cycle.

  3. It’s good to see Lyle’s take on a very confusing situation to the scientifically inclined. I’ve personally seen people who are accurately logging their calories, measuring the exercise caloric deficit through the bodybugg and for 3 weeks straight there is 0 movement on the scale….WTF? I was like “where the hell is this energy expenditure going?”

    I had one friend who was creating a 7,000 calorie deficit each week who was plateauing. She was trying to get the last 5 or 6 pounds off of a pretty lean body (for her genetics) and was just stuck. She was already eating so few calories that I couldn’t play with her deficit ratio of intake/exercise. Now, looking back, she was having 0 refeeds because at the time (7 years ago) I simply though that the advantages of “free days” or structured re-feeds were purely psychological and this chick had the dedication and fortitude to push through it.

    Then some trainer at her gym, (who honestly knew nothing, he was one of those trainers who just spouted out the popular dogma of the time and made everyone do forced reps) told her that she needed to eat every 2 hours to “fix her metabolism” ugh. She asked me about it and I laughed and said try eating 5 or 6 times a day while staying around 1200 calories (this was .08 times her bw at this point). But she did it anyway and logged her food.

    7 days later she was down…..6 pounds!!! WTF! I looked at her logs and she ended up eating like 2000 calories a day a freaking increase in 5,600 calories over the previous week….and..she..lost..weight. Her training logs showed stable strength and endurance so it wasn’t from doing more work. It made this shit head trainer look like a genius and it made me look like some schmuck. I’m still not over it obviously lol.

    But even after this article, I still can’t figure this shit out. Ok I guess it could have been 6 pounds of water weight, but this chick didn’t look bloated, if that’s even a reliable indication of water retention. It CANT be from an increase in work because she measured all her sets/reps and cardio machine settings and time. It seriously can’t be from an increased metabolism either, even if somehow she had a whopping 30% decrease in her RMR and she magically returned it to normal that still wouldn’t account for a 7 pounds weight loss. Not that that would ever happen. From that moment on she ate 1800 to 2000 calories a day (an addition of 600 to 800 calorie a day) continued to do her massive amounts of cardio and she reliably continued to lose 1 to 1.5 pounds a week.

    So now I’m wondering if sometimes (and Lyle alluded to this at the end of this article) you can go too low on the caloric intake and/or too much expenditure via exercise sufficient to cause weight stalls in the susceptible. But is it really situation where it is mostly water weight that’s being retained and fat is continue being burned? In a situation like my example sure it can because it was a 2 or 3 week stall with a massive weight drop and no one could burn 6 pounds of fat in 7 days in her metabolic situation. But then you hear stories about the people on the biggest loser who find that increasing caloric intake maintains their weight loss and this is in a chronic setting. You also her about this in peoples P90X logs. The trend I see (and again Lyle mentioned this) is heavy aerobic exercise with a major caloric deficit. I personally haven’t seen as many stalls when people are getting most of their deficit via extreme caloric restriction.

    But in the end, I still can’t let my mind accept that increasing calories=more fat loss.

  4. As noted in the article, I’ll be addressing why too much activity + too much deficit causes problems or at least can cause problems in some people. And what I think is going on.

    And the sooner you accept the sometimes less is more, the better off you and your clients will be. More is not always better. In fact, in many situations, it’s far far worse. This is true of all types of training as well as dieting.

  5. Thanks for the response Lyle. You know I just assumed that the whole less is more (in terms of caloric intake) was purely to the benefit of adherence and preventing psychological crashes and physiological overtraining. I new that less is more when it comes to weight training (compared to constant training to failure and drop sets, etc NOT training frequency necessarily). I used to think, create the biggest deficit that the client could stand and wouldn’t majorly impact training and you’re good to go; it’s all math at that point. But it’s these dammed stalls that just confused the hell out of me. There are nuances here and, as you mentioned, there is a huge difference between someone starting a diet and someone who has been dieting for months.

    What I’m struggling with is not the diet breaks and re-feeds for short term stalls, it’s the thought that slightly reducing the daily deficit will create sustained and weekly loses versus a large daily deficit. But like you said…science, moderation and maybe a bit of magic.

    Thanks for the advice.

  6. In one sense, though, doesit matter whether you get 1-1.5 lbs/week for 4 weeks or 4-6 at the end of 4 weeks? The end result is the same, assuming the person doesn’t give up in that time frame for a ‘lack of results’.

    Of course that assumes that the person does the things needed to bring on the LTDFLE (and usually folks will counter a lack of results with HARDER dieting and training which usually only compounds the problem).

  7. Very timely article. I’ve just completed Warp Speed Fatloss 2.0, which uses a low carb diet over 28 days. I’m hoping I’ll experience LTDFLE over the next week. 🙂

    I’ll try to shoot for your 100-150 grams of carbs a day recommendation over the next two weeks.

  8. Even though I have been bodybuilding for over 30 years (I’m a soon to be 53 year old woman), there is still so much to learn about nutrition and training. I’m always looking for new ways to better myself competitively.

    You are so right in saying that sometimes “less is more”. I have learned that the hard way over the years. I started bodybuilding in the decade where the saying was “no pain, no gain”. I’m still an advocate of training hard but these days, this bod needs a shorter workout that is intense and under an hour – I do very well on a 4 day split program. I’ve made better gains and improvements in my 50’s than I did in my 30’s. Of course, when you are younger, you don’t want to listen to such advice and just train balls to the wall, all the time.

    The research you are doing in nutrition is fascinating and I can’t wait to apply what I’ve learned from your books which I have recently ordered. Also very intrigued by the intermittent fasting concept as well as I’ve seen on the Lean Gains website. Just like we have to cycle our training regimen, so too we also have to cycle our nutrition because we can get “stale” consuming the same macronutrients all the time.

    I feel that body composition or recomposition should be a lifestyle and lifetime goal of everyone who pursues living a more healthy lifestsyle and staying lean for life.

    Thanks for being here to open people’s eyes and minds to what really works!

  9. Very interesting stuff, as usual. Personally I tend begin to retain a lot of fluids after couple weeks of dieting and especially if I go overboard (eat too little or do too much exercise). This causes frustration as it is hard to evaluate the progress and I easily misjudge the situation thinking that it’s because of not dieting hard enough. Therefore I restrict and screw things even more. Last time that I did some sort of dieting, eating more helped a lot. However, I still retain some fluids. After finishing, I noticed that after a week the extra fluids disappeared and I looked the way I was supposed to look. So, I do agree with you Lyle, magic seems to take place after you have finished your dieting. The question is that should those who prepare for natural bodybuilding competition try to be ready quite early before D-day? Maybe a week or 2 before competition in order to be best possible condition? After e.g. week of controlled refeed one could make final preparations without upsetting the body?

  10. The problem is holding that condition since water balance can shift day to day and hour to hour. You might look great 2 weeks out but then what. You’re not going to maintain that peak for 2 weeks and it would also mean starting your contest diet that much earlier to fit it in.

    What I do think is an implication is this, and this idea has been around forever: the simple fact is that if youre not ready a week out, you won’t be ready. So the diet should effectively be over 7 days out (maybe 5 at the most). At which point start setting up for a carb-load (if you do one) or at least bringing calories back towards your new (low) maintenance so the body can release water. It’s trying to diet to the Thursday before the show, then looking great Tuesday 3 days too late that you wan’t to avoid.

  11. Very interesting, Lyle! 🙂

  12. Very interesting article – was looking for an explanation of this “phaenomen” LOL… Enjoy this period… I am down at 7% bf after a long dieting and very clean eating period. Now I had two hardcore refeeds, still staying at 7%, uge 8-pack – BJ-ready-style LOL ;-).

    Currently I am just asking myself how long I can go on like this… I mean with those huge calorie refeeds – when will I again start to gain fat? I did diet down to 7% bf in a EOD-refeed style, always one day with low carb low calorie = strategic cardio day and the next day weight-day with calories at maintenance and some carbs. And then additional calories on weekends (700+1400).

    Anyway, wouldn’t have been so successfull without lyles books, articles etc. – awesome work my friend!

  13. So quoting this “LTDFLE only occurs after fairly prolonged actual dieting”
    Can LTDFLE actually be triggered by RapidFatLoss? I mean does it have to be prolonged in duration or just extreme in caloric restriction as well?

  14. how can i return back to form after this…i panicked cuz i lost weight after i went back to eating regularly and maintenance. Everything in me got smaller and it makes me wanna cry…

  15. I usually don’t write comments but feel very compelled to do so now. I cannot believe I stumbled across this article. I have noticed this effect for ages and when I try to describe it to people they think I am off on some tangent! I always called it lag time. I think it goes both ways too, meaning when starting to diet/train and also when stopping u get gains a great a couple weeks out. Your theory on gene expression would support this. Let’s say two weeks to turn the genes on then two weeks before they shut off at the end of diet or heavy training program.
    Love the internet, and kind of excited that others out there witness odd phenomena too. I wonder how many other things we notice and never speak of them but rather they are just passing thoughts or theories in our heads.

  16. Yes, I agree 100% with you that it goes both ways. When you’re done bulking and start dieting, it always feels like you keep getting fatter for a couple of weeks. Long-Term Delayed, uhh, Fat Gaining Effect (LTDFGE) or something. There’s just this weird inertia sometimes. This is just the opposite of that.

    Thanks for the comment!

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