Friday, April 27, 2012

Weight Loss Reduces Biggest Losers' Metabolic Rate by 20%! 7% More Than Predicted by Another Useless Formula

Image 1: How many Biggest Loser ranches like this could you possibly build from the billions of dollars the American Health Care System alone is paying for drugs to manage instead of tread the obesity epidemic? And would it be worth it?
If you really want to get me started, you got to ask me "how many calories" you are supposed to eat. In my whole life, I have never even seen let alone eaten such a thing as "a calorie" and although I have no scientific evidence for that, my personal experience tells me that meticulous and even anxious calorie counting can make you skinny and crazy, yet never lean and sane. Aside from food quality factors, which certainly have a major impact, the real, fundamental fallacy of the "cut your calories" approach to weight loss is the ubiquitous ignorance towards the adaptive capabilities of the human body. A topic, I have broached several times before - yet obviously to no avail, other than the constant decry that "dieting will downregulate your metabolism"; of course, it will! If you weigh less, you need less energy.

You count calories? You must have a DEXA scanner, a ton of doubly labeled water and a Finnigan MAT 252 dual-inlet gas isotope ratio mass spectrometer, then, right?

And in view of the complexity of the human body, you should not be surprised that neither the resting nor the total energy expenditure exhibits a linear or otherwise deterministic association with your body weight and activity level. That even smart scientist, sophisticated mathematical formulas and accurate body fat, lean mass, etc. parameters (something you will by the way never have unless you got a decent DEXA scanner next to your scale in your bathroom ;-) cannot calculate the exact amount of energy you need has only recently confirmed in no one else but The Biggest Losers - in this case the actual "losers" from the TV show (Johannsen. 2012; thanks Steven Arcera for posting the link on my Facebook wall).

"Big losing" reduces your energy expenditure by -9% in six weeks

Some of you will know that the Biggest Losers are no strangers here at the SuppVersity (cf. my discussion of Ashmadi. 2011); not because I am a fan of the show, but rather because the TV producers worked hand in hand with a group of scientists who are now coming out with some relatively well-controlled (in the actual "camp" phase; 13 weeks for the last losers standing ;-) data on the effects of a weight loss program that consisted of a reasonable reduction in energy intake (-30%; pretty reasonable for someone who is as obese as a Biggest Loser - for leaner folks I would yet suggest to try to hover at max. -20% of their maintenance food not calorie intake and that for no longer than 6 weeks followed by a maintenance phase!) and an insane amount of (mostly) aerobic exercise.
Figure 1: Changes in BMI, fat free mass (FFM), fat mass (FM) and body fat (%) of the Biggest Losers after six weeks in the camp (total time in camp 13 weeks for the winners) and at the 30-week follow (left); fat / fat free mass weight loss ratio (right) and body weight change over the whole 30 week period (upper right; based on Johannsen. 2012)
And if you take at the results of the 11 (our of 16) competitors who survived the first 6 weeks, the results were actually not too bad. The subjects lost a whopping 7% of body fat (12kg!) and only 4% of their fat free mass. This yields a fat / fat free mass weight loss ratio, i.e. the ratio of the amount of fat to the amount of fat free mass (this is not just muscle, but also bone, organ weight, etc.) the subjects dieted and exercised away, of 4.8 - or put more simply. The subjects lost "only" one kg of fat free mass per ~5kg of body fat, which, if you come to think about it, is not all too bad. Most surprisingly, the weight loss did not stall (cf. figure 1, small graph), when the big losers went home after 13 weeks. In fact, the average weight of all sixteen participants, including the "real losers", who gave up before week 6 had declined by -40%(!) at the 30 week follow up and the "average loser" (7 men, 9 women) had lost 47kg of pure fat (-66%!) - if those are "the biggest losers", I guess the "biggest winners" are soon going to walk on the Karl Lagerfeld's catwalk ;-)

Are the Biggest Losers all winners, after all?!

The biochemical and blood pressure readings at the follow up support the notion that, overall, "housing [obese people] in an isolated ranch[es] outside Los Angeles" could be the long sought-for solution to the diabesity epidemic - a wonderful success story, if we (or rather you my dear American friends) had enough isolated ranches, personal trainers, television crews etc. to house and pamper 36% of the population (obesity rates according to NHANES data from 2008).

And though I am actually not sure if it would cost so much more than the billions of dollars the American Health Care System is investing year by year in drugs to manage, instead of to cure obesity, diabetes and co. if they actually constructed respective facilities, hire trainers and staff, revised the dietary guidelines and took all the other necessary measure to get down to the root of the trouble (and these are not just carbohydrates!), we all know that this is not going to happen.
Figure 2: Predicted and measured resting metabolic rate (RMR.) and total energy expenditure (measured using doubly labeled water analysis) of the subjects at week 6 (in the camp) and on 30 wk follow-up (left); changes in adipokine and thyroid hormone levels from baseline at 30 wk follow up (data calculated based on Johannsen. 2012)
If you take a closer look at the data in figure 2 it is also questionable how sustainable the results of these efforts would be, if we do not eventually step back from the typical western "more is more principle", according to which it is good and highly desirable to eat copious amounts of (junk-)food without any of the natural side effects this practice has.After all, the -20% reduction in metabolic rate (-560kcal/day), the scientists attribute to "centrally mediated with a parallel action on the hypothalamic-pituitary-thyroid axis", because ...
[...] the magnitude of metabolic adaptation was not significantly correlated with circulating T3 changes but was as-sociated with the change in TSH such that those with the greatest increase in TSH had the least metabolic adaptation.
and an average resting metabolic rate of  1764kcal/day will make it difficult to remain weight stable in a society where eating as much as possible (without gaining weight, of course) is perceived as desirable.

"More, more, more, ... I want to eat more!"

Image 2: Could Adelfo's physique partly be attributable to the fact that eating as much as possible is not among his goals in life?
If we disregard any appetite dysregulation and cravings for junk food, and take an objective look at the total daily energy expenditure of the subjects (in the absence of drill instructors enforcing the 90min/day of intense aerobic exercise), even the calories in vs. calories out principle would leave more than enough room for these big losers to eat to satiety - 2906kcal/day (!), this is ~27% more energy than our mutual friend Adelfo Cerame is consuming at the moment.

So, let me ask you this: What is the underlying problem here? Is it really the downregulation of the metabolic rate, or isn't it rather the combination of our insatiable appetite that grew from year to year on the standard western junk / convenient food diet with subsequent and intermittent unbalanced starvation diets, which makes everyone moan about a "sluggish" metabolism, these days?