Originally I was going to do a full writeup of the recent study making the rounds suggesting that both low- and high-repetition training generate the same muscle growth but I’m going to save that until next week; this topic makes more logical sense given last week’s video on BMI and weighing frequency. It was also stimulated by a private message I got on FB regarding the topic.
That topic, of course is the idea of metabolic damage, something I have written about on the site previously. But rather than write something new, I just got permission from Alan Aragon to reproduce an interview I originally did for his (highly recommended) research review. It’s only $10 a month and chock full (that’s right, CHOCK!) of the most current research on diet and training along with interviews with top current coaches and feature articles on all topics big and small. Go subscribe, subscribe now.
Ok, so what exactly are we talking about here? As originally claimed, metabolic damage referred to a phenomenon wherby dieters (typically females) who had been on low calories and performing a large amount of cardio (i.e. typical physique sport contest prep)
- Stopped losing fat despite maintained low calories/high activity
- Started regaining fat despite those same maintained low calories/high activity
Hence their metabolism was damaged. I’m mainly bringing this up as the original concept has been somewhat, err let’s be nice and say, “modified” from the original (now being called metabolic adaptation, a concept I’ve been personally writing about for over a decade in pretty much all of my books).
And with that out of the way I reprint my original interview with Alan Aragon (did I mention that you should subscribe to his research review). Everything in bold is Alan, the other dense walls of texts are me.
My big question for you is related to the whole “metabolic damage” concept. Coaches and competitors involved in bodybuilding & physique contest prep – predominantly women – often report cases of consuming very low calories (i.e., in the 700-1000 kcal range), combines with high volumes of cardio (i.e., 2+ hours per day), and all this without any weight loss. What are your initial thoughts on this, as far as validity and/or mechanisms behind it.
First and foremost, I have myself written about how the odd combination of very low calories and excessive cardio can, in some people, cause problems. Some of it is metabolic which I’ll come back to. But most of it is simply due to one thing: water retention. It’s a little known fact that cortisol has cross-reactivity with the aldosterone receptor (aldosterone is the primary hormone for retaining water). But while cortisol only has about 1/100th the affinity for the receptor, there can be about 10,000 times as much. We know that cortisol causes water retention (Cushing’s patients who are often on high-dose cortisone have this problem).
- Now, dieting raises cortisol.
- Cardio raises cortisol.
- Mental stress raises cortisol.
So combine your typical headcase female dieter (who is already mentally stressing themselves out), add a massive caloric restriction, add tons of cardio. And cortisol goes through the roof. And this is worse in some personality types. You can always tell them on Internet forums, they type in all caps with lots of !!! (Subject line: NEED TO LOSE WEIGHT NOW!!!). You can sense the stress in their life in how they write. And what these people do other than mentally stressing themselves out is further physically stress themselves out. And when weight loss stops, they stress harder, cut calories harder, do more cardio. And make it worse.
I mean, hell, a woman can easily shift 10 pounds of water weight across her menstrual cycle. That’s not uncommon in this kind of stress condition. Now add to that the fact that a typical female dieter if she’s lucky, might be getting 1 pound of true fat loss per week. If her stress (due to mental, diet and physical factors) is causing her to retain 10 pounds of water it will appear that her diet is not working for 10 full weeks. During which time she will lose her absolute shit.
What always works in these types of dieters is chilling the fuck out (weed would help too). Raising calories, lowering cardio, a good lay. There’s no metabolic magic, cortisol finally drops when you get them stop being crazy for a couple of days and they experience the magical whoosh (or the LTDFLE, check my site for details). Boom, weight drops by 5+ pounds overnight.
All water. Well mostly. But clearly they didn’t have a 5 pound deficit in one day. They just finally dropped the water they’d been holding.
So that’s part 1. Any questions before I move on to part 2?
Clear so far, please continue…
So, for the most part I think that’s a lot of what’s going on the fat loss is just being masked by severe water retention. I say this simply because getting folks to rest a couple of days, raise calories (especially from carbs, the increase in insulin lowers cortisol levels) and “refeed” invariably causes that big weight drop/whoosh effect. It has to be water.
However, that isn’t to say that there aren’t metabolic effects that can occur due to that combination of variables (low calories and high activity).
I’m going to assume (and hope) that your readers are familiar with leptin. If not, basically it signals to the brain (and elsewhere) about energy stores in the body (and how much you’re eating) and when it drops it induces much of what is often incorrectly called the “starvation response” or “metabolic damage”. I say incorrectly because this simply represents a normal ADAPTATION to dieting that occurs because the body, fundamentally, doesn’t give a damn that you need to look good on stage. It wants to keep you from starving to death.
So falling leptin causes a host of things to occur: metabolic rate slows, hunger increases, you get lethargic, thyroid goes down, testosterone drops, and a whole bunch of other shit goes wrong.
Pretty much everything bad that happens with dieting is controlled, to at least some degree by leptin levels especially at the level of the brain. On that note, studies that have given leptin replacement following dieting show a reversal of these effects; but don’t get your hopes up leptin is an injectable drug and still many hundreds of dollars per day. But drug using bodybuilders have basically been sort of fixing all of the peripheral problems with drugs: anabolics to counter falling testosterone, thyroid meds for thyroid, cortisol blockers, appetite suppressants, stimulants to keep energy levels up. Raising leptin would be more elegant (as it would fix the problem centrally in the brain) but difficult. Refeeds and full diet breaks (discussed on my site and in my books) help a lot. Injectable leptin would be skippy but way too expensive. The leptin-mimicking supplements are all bullshit.
I bring this up because cortisol, among its other fun features, induces leptin resistance in the brain. Like insulin resistance in skeletal muscle (where the cells don’t respond to insulin properly), leptin resistance means that what leptin is around doesn’t send a sufficient signal to the brain. So in those folks who are already psychotically stressed and cutting calories and doing too much cardio, the massive increase in cortisol will have that effect centrally in the brain.
But, wait…there’s more…
WHOOT!!! Keep going.
Ok, so finishing up, which is not to say that there is not a metabolic adaptation/adjustment to dieting and fat loss; that’s really never been up to debate. Once again, we have this leptin system that basically evolved to keep us from starving to death. In that regards, a lot of people think of leptin as an anti-obesity hormone but this is incorrect. Leptin does very little to keep us from getting fat (which had no evolutionary disadvantages until recently); leptin exists to keep us from starving to death. And fundamentally, dieting is just controlled starving to death. But the same things occur.
Now the determinants of total metabolic rate are multi-fold, typically divided up into the following four categories:
- BMR: Basal metabolic rate (also called RMR or resting metabolic rate): this is just the basal processes to run your body.
- TEF: Thermic effect of food, the extra calories you burn from eating. Quick-estimated at 10% or so it actually depends on the nutrient eaten.
- TEE: Thermic effect of exercise. The calories burned through exercise.
- SPA/NEAT: Spontaneous physical activity/Non-Exercise Activity Thermogenesis: This is a newer category and separate from thermic effect of exercise, it’s the calories you burn moving around, fidgeting, changing postures. It happens to be massively individual.
But all 4 respond to changing food intake and body weight. So as soon as you start dieting, TEF automatically goes down a bit since you are eating less food. Less food means less TEF (note that this has NOTHING to do with meal frequency). BMR goes down as you lose weight because a smaller body burns fewer calories. So do the calories burned during exercise; at any given absolute intensity, a smaller person burns less calories.
Again, SPA/NEAT is a big question mark since it varies so much. But you generally tend to be more lethargic during the day when you diet, so you end up moving around less, burning fewer calories in total. And while it’s great to think that you can consciously impact this, NEAT is subconscious. At best you can offset it with more exercise (part of why competitors usually raise cardio volume or intensity during a cut).
Even with that said, research has typically divided the drop in metabolic rate into two different components. One part is simply due to the reduction in bodyweight. As I said above, a smaller body burns fewer calories and there’s really not much that can be done about this (wearing a weighted vest might have a small impact on at least TEE). Get lighter and you burn fewer calories.
There’s nothing you can do about this short of NOT LOSING WEIGHT. Which goes against the point of a cut. And yes, I’m using weight and fat interchangeably here: for anybody but a drug-using competitor, fat loss is going to mean weight loss. Don’t get picky.
But there is also evidence for what is called an adaptive component of metabolic rate reduction. Let me explain. Let’s say that someone loses twenty pounds and based on all of the math you’d expect a drop in metabolic rate of 10%. But when you measure it you actually see a reduction in 15%.
That is, the drop in metabolic rate is greater than what you’d predict based on the drop in bodyweight. That extra 5% is the adaptive component of metabolic rate reduction. And it’s hormonally driven, the drop in leptin, the drop in thyroid levels (conversion of T4 to T3 is impaired on a diet), there is a drop in sympathetic nervous system activity (part of why the ephedrine/caffeine stack helps, it offsets this drop), you get the idea.
The thing is that not every study has found this. Some do some don’t. A lot of it depends on starting body fat, the length of the diet, genetic individuality and all that stuff. But in dieting bodybuilders or fitness people, it is going to have an impact. But the preponderance of studies say that it does exist; I’d certainly expect it to occur in lean hard dieting physique athletes who is who we are concerned with (typically when it doesn’t show up is in studies of extremely overfat individuals whose hormones don’t really get mucked up until they have lost a lot of weight).
A-ha, you say, now we have an explanation for the so-called metabolic damage (and note that I’ve seen this term used to refer to a couple of different things: one is that weight/fat loss stops despite a huge deficit; a more extreme claim is that competitors start to regain fat even in the face of low calories/high activity). But wait, there’s more. And yes I’m almost done.
Ready for the big payoff?
I would have to be a crazy person to stop you here. Let it rip, Brofessor McDonald.
Actually I only have a BB (Bachelor of Bro-osity). I didn’t feel like doing advanced academic work to get my MB (Master of Bro-osity) or BrD (Doctor of Bro-osity). Note: I told you this was email and Alan and I were being a little bit silly.
Anyhow, I’ve looked at water retention (which I think is a big part of this) and some of what goes into metabolic rate adaptation. And yes it does occur. No one is doubting that. But that raises the important question. Is the drop in metabolic rate that occurs during dieting sufficient to stop weight loss in its tracks despite a claimed low caloric intake and high-activity level?
Actually, before I get to that, let me expand on the above sentence. You might note my use of the word “claimed” in regards to low-caloric intake. Because there’s an issue here that often gets overlooked. One of the known adaptations to dieting and getting lean is a massive increase in hunger. And even with the strongest willed competitor/dieter, often it becomes overwhelming. Geared bodybuilders often use appetite suppressants, the EC stack has been used perennially but the reality is that getting very lean means being hungry.
And that means binges. You can go to endless forums where competitors, men and women alike report losing their minds and going on a binge of varying types. Some go carb-crazy, some of the “clean-eaters” will have that one taste of something forbidden and go on a Blizzard binge that makes them sick. But most don’t really like to talk about it.
That is, these binges, as often as not go un-reported. So the dieter who is claiming 1200 calories with tons of cardio tends to often conveniently “forget” about the day they spent eating every piece of garbage they could stuff down their gullet. And in light female competitors, if the binges get crazy enough it can readily offset the deficit being created during the week.
But irrespective of that, let’s address what seems like a fairly simple question: Can the drop in metabolic rate, due to the drop in bodyweight and the adaptive component EVER be sufficient to completely eliminate true fat loss?
And the answer, at least based on the last 80 years of studies into the topic (in humans, NOT animal models) says no. Perhaps the classic study in this regard was the oft-quoted (and oft- misunderstood) Minnesota Semi-Starvation Study. In it, a dozen or so war objectors got to avoid going to war and arguably got into something worse. That is, researchers wanted to study long- term starvation as might occur during war or famine or being held in a prisoner camp.
Specifically the men were put on 50% of their maintenance calories, subject to forced daily activity (walking, NO weight training) and basically had their lives controlled and managed for 6 months. And in various sub-analyses, it was found that, by the end of the study the total drop in metabolic rate was nearly 40%. That is, of the original 50% deficit in calories, 80% of it had been offset. Of that 40%, a full 25% was simply due to the reduced bodyweight. Again, lighter bodies burn less calories and there’s no getting around it. But that also means that the adaptive component of metabolic rate reduction was only 15%. Which is about the largest drop ever measured (most studies measure less).
But here’s the punchline, the men had also reached the limits of human leanness. They were in the realm of 4-5% body fat by this point in the study. Even though their fat loss had basically stopped (and at some points in the study WEIGHT loss stopped due to severe water retention) it didn’t occur until they reached ultimate leanness (NB: the claims of bodybuilders to be 2-3% bodyfat is a measurement error). And even they were still losing tiny amounts of weight/fat. It just wouldn’t have amounted to much since most of the deficit had been offset by the metabolic rate reduction.
Now some will (and may rightly) point out that the study was only in men and women’s bodies may be different. And they are correct; I’ve written about this myself (my odd little book on Bromocriptine talks about it in some detail). Certainly women’s bodies do some strange things in this regard, they are more evolutionarily, err, evolved, to hold onto calories and fat stores than men (and there’s some profoundly goofy shit that can occur where they shift upper body fat stores to their legs, discussed in my book The Stubborn Fat Solution). So I suppose it’s conceivable that there might be a woman or three for whom this could occur. Maybe. Not that that woman has ever shown up in a well-controlled study in 50 years. But I suppose she might exist. She probably rides my invisible unicorn.
Because in no study that i have ever seen or ever been aware of has the drop in metabolic rate (whether due to the drop in weight or adaptive component) EVER exceeded the actual deficit whether in men or women. Fine, yes, it may offset things, it may slow fat loss (i.e. if you set up a 30% caloric deficit and metabolic rate drops by 20%, your deficit is only 10% so fat loss is a lot slower than expected or predicted) but it has never been sufficient to either stop fat loss completely (or, even to address the even stupider claim being made about this, to cause actual fat gain).
But even when the drop in metabolic rate is massive, sufficient to drastically slow fat loss, even when it occurs it’s only when that person’s body has more or less reached the limits of leanness in the first place. So for ‘hundreds of women who are self-reporting this in emails’ to a certain coach to exist, well; just let me call that what it is: bullshit.
I think what’s really going on is you have a bunch of neurotic crazed female dieters, who are misreporting their food intake (especially the crazy food binges we KNOW happen in this population) and who are holding onto massive amounts of water due to the combination of low calories, high-cardio and being batshit stressed mentally about the whole process. And who magically start losing fat again when their poorly controlled 1200 calories becomes a well-controlled 1250 calories, well….you’ll have to call me incredulous about the whole thing.
Because the science doesn’t support it in any way shape or form. No study in humans in 50 years has ever shown the claimed phenomenon. I mean not ever. Not a single study showing truly stopped fat loss in the face of a controlled deficit much less fat regain. And with plenty of other mechanisms (like water retention) to explain the “apparent” lack of fat loss that make more logical sense (Occam’s razor for the win).
And that’s my take on the issue. Now it’s time for a nap.
- Permanent Metabolic Damage – Q&A
- Why Big Caloric Deficits and Lots of Activity Can Hurt Fat Loss
- The Long Term Delayed Fat Loss Effect
- Dietary Restraint and Cortisol Levels – Research Review
- More from the Mailbag