James Krieger on the Biggest Loser study that's going around
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Additionally, I'm not saying "disregard the study", I'm saying that I question its relevance to the vast majority of people.
Well it seems to be relevant at least to the extent of that once you become fat, you have - to some degree - changed how your body metabolizes food for the worse. It might be a fraction of what that study suggests, but still applicable.0 -
kportmanshark wrote: »Additionally, I'm not saying "disregard the study", I'm saying that I question its relevance to the vast majority of people.
Well it seems to be relevant at least to the extent of that once you become fat, you have - to some degree - changed how your body metabolizes food for the worse. It might be a fraction of what that study suggests, but still applicable.
IIRC the usual is 100 -200 calories maybe?
Biggest Loser: 6 hours of cardio w/3,500 calorie deficit per day
Normal Aggressive Diet: 6 hours of cardio w/3,500 calorie deficit per week2 -
kportmanshark wrote: »This is not the only study to show this, but the magnitude of change in the study is quite high.
Then there is likely more validity to it than we are giving it credit for. It might be exaggerated here but the point of our bodies being permanently changed seems likely if there are multiple studies.
Way I look at is that it was my bad behavior and laziness that made me into a hamplanet so I'll just have to work harder to make up for that now that I screwed up my system now that my bmi is reasonable again. It's bad news but that's life. I can see why we might want to disregard these outcomes because its depressing to think about that as a reality, but it very well might be true (perhaps to a lesser degree than this study implies - partially because our losses aren't as dramatic, but still true).
Anytime you have a study, it's a good idea to look at study design and determine what applicability it may have.
Given the ridiculous nature of the diet and training program that is used on the biggest loser, I would question the applicability of the study results to populations that use diet and training programs more representative of what the general population does.
And while that spans a very wide range of training volumes and calorie deficits, that range likely doesn't come anywhere near the absurdity of what happens on that show.
Well said. Comparing the Biggest Loser contestants with average folks doing this at home is comparing apples and oranges.1 -
kportmanshark wrote: »I'm a skeptic of the study also, but it brings some interesting topics up.The thing is, even with the large reduction in RMR, total daily energy expenditure did not show any signs of adaptation, and TDEE is what really matters anyway, not RMR.[/i]
Indeed it is, at about 2000 out of the 3000+ TDEE in this case.Also when they talk about leptin, the baseline leptin was when they were their fattest. I would think (but don't know) that when you are that big the body would be outputting lots of the "feel full" hormones because it isn't as worried about not having enough fat stored. Once at a lower weight I'd expect there to be less leptin since the body wouldn't be as worried about having too much weight.
When they say the leptin is 50% of where they started when they were fat, do we know if that's a normal situation or if their levels were just super high when they were that big?
Leptin goes up pro rata with fat mass when we get fatter, and crashes when we diet, and comes back up when calorie balance is restored. Nothing to see here I suspect.
People like to talk about leptin a lot, as we only found it in the 1990s, but there seems to be no direct measurable effect of leptin on weight loss or metabolic rate and no proposed mechanism either.
It's interesting to see the noise coming out of the exercise community about this, as it's exercise that is on trial. They were required to eat a minimum intake on BL so it wasn't a crash diet or total fast.0 -
I'm going to jump in here a bit.Additionally, I'm not saying "disregard the study", I'm saying that I question its relevance to the vast majority of people.
I'm going actually say that, "disregard this study as a reference to weight loss". Because the study is actually an interesting exercise of reality TV and not something that people should be practicing anyway and since it has little relevance to training or proper weight loss it really is of interest in terms of methodology or, like the Minnesota experiment, in terms of extreme function. It should not guide individual choices.My friend James Krieger posted this on facebook so I wanted to share it here since there's a lot of buzz going around about this.
James is a researcher and quite brilliant. He also recently spoke at the PTC conference in the UK on Non Exercise Activity Thermogenesis (it was outstanding).
Anyway, dude is brilliant so anytime he says something I pay close attention.
"A lot of talk has been going around about the recent Biggest Loser study. I've been discussing it with Spencer Alan and Evelyn Carbsane, and the thing about studies like this is that the devil is in the details.
Those of you who saw my recent presentation in the UK may remember me discussing the measurement of RMR, and why it is absolutely critical that subjects are weight stable when you measure it. RMR is very sensitive to energy surpluses or deficits, and can give an illusion of being higher or lower than normal if your subjects are not truly weight stable. If you look at the data in the Biggest Loser study, you will see that the researchers had the subjects weigh themselves daily at home on a scale that transmitted data back to the researchers. They had 16 days of data, and used statistical regression to see if weight was stable over that time. Basically, they looked at if the slope of the line was different from 0 (a flat line). It was not significantly different from 0. However, the kicker is that the P value was quite low at 0.1, which is not far from being statistically significant (which is considered at 0.05 or less). The thing is, statistical significance is nothing more than an arbitrary threshold, and with small sample sizes like in this study, you can often mistakenly call things "not different" when they are (a type II error).
On average, the subjects were losing 0.5 pound per week. Yeah, it's not large, it may have not met the threshold for statistical significance, but this data doesn't give me much confidence that the subjects were weight stable. It tells me the subjects may have been in an energy deficit when they were measured, which would make RMR appear artificially lower than it really is.
The other thing is that this study is at odds with other research in this area, which has shown that downregulation of NEAT/spontaneous activity is much greater than adaptations in RMR with weight loss. The Biggest Loser study showed no downregulation of physical activity, yet a large reduction in RMR. That makes me suspect that the subjects, knowing they were going to be measured in a follow-up, were actively trying to lose weight and exercising heading into the follow-up. This would explain the lower RMR (because they were in a deficit), yet the lack of reduction in physical activity (because they were exercising).
I've always considered the data out of Rudolph Leibel's lab to the "gold standard" in this area, because he has subjects housed in metabolic wards for long periods of time, matches subjects to controls, and uses formula diets to meticulously control their calorie intake and ensure weight stability. Leibel's work has shown only minor reductions in RMR, with most of the adaptation occuring in NEAT/SPA. Unfortunately, Leibel has never had subjects with such large scale weight losses as the Biggest Loser, so it's still possible that extreme losses will result in more extreme adaptation. Still, I don't think the adaptation is as high as what is being reported in this study, due to the limitations discussed here.
The thing is, even with the large reduction in RMR, total daily energy expenditure did not show any signs of adaptation, and TDEE is what really matters anyway, not RMR.
The depressed RMR is a speculation which is based on assumed behaviour of the contestants prior to the lab measures. It might hold, however there are some counter arguments. Why would we not make the same assumption for the RMR evaluated at the end of the competition period. One could make the argument that both periods would result in artificially depressed RMR if this process was being seen.
I agree that down-regulation of NEAT / Activity is generally seen in other studies - if fact it seems to be the most consistent factor when adaptive thermogenesis/metabolic adaption comes into play in the publications. The absence here, suggests that these individuals are still highly active. And even if their RMR was artificially depressed, correcting for that, would still suggest that these individuals are highly active. These people, who know how to lose weight rapidly, were not actively trying to do so with a loss of half a lb per week but still, the risk of type II error is real at this inclusion number. If Krieger's assumption is right then why would we not correct the 6 year RMR with the depression seen post competition? The data would still show an RMR depression, possibly less dramatic (somewhere in the - 225 kcal/day vs the 500±207 kcal reported). It's still close to a 10% RMR depression, close to what is seen in other literature.
As an aside, take a look at the ratio of TEE/RMR for the pre, post and 6 years follow-up. They are: 1.45, 1.50 and 1.80. These "activity multipliers" suggests that somehow at the 6 year follow-up these people were somehow much more active? Actually, this brings up the point that the researchers caught and that we should pay attention to: highly active obese individuals move more mass around and the linear activity multipliers were developed for non-obese individuals. When physical activity is corrected for weight, the post and 6 year follow-up is consistent (and higher than pre-contest).
So, yes, TDEE is more important than RMR but even more important is the endpoint: weight loss. Despite significant efforts, and an activity level that is pretty consistent with the activity levels achieved at the end of the contest - these individuals have on average gained back over 60% of their weight loss while mostly remaining active (that last p value suggests a lot of variance there).
So while the adaptation may not be as high as what is being reported - it still seems to be there and furthermore, the other data suggests that these extreme losses are a waste of effort.
On the overall study design, for 16 people it is unfortunate that they only have 3 evaluation points. Particularly weak is that only 1 point is post event. Making such conclusions off one measurement is weak and I would have loved to have seen a 3 year or 6 year and 3 months data point.
Finally, it's a shame that the HOMA-IR values in the study were not discussed by the researchers.
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The BL study was interesting. As someone who's lost 100 pounds and kept it off for several years I know it can be done. Obviously how they lost the weight completely differed to how I lost the weight. I took it slow, over about 2-3 years and they lost in a matter of months. I slowly incorporated exercise and they started working out hard from day one. With that said, I do have to watch what I eat and I exercise 1-2 hours a day although admittedly I love to work out I have a cheat day and I allow myself treats but I know that cannot be an everyday thing or I will be 230 pounds again in no time. I feel for them because they lost their weight in public and now they've gained the weight back in public too. I can't imagine what that must be like or the pressure they feel! It makes me very happy that I went at this slowly and very much in private!5
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I can't believe are taking this study to heart. You can't compare people who lost extreme amounts of weight in a short amount of time via super unhealthy methods to the general population. Not to mention that it was a sample study of 16 people.1
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Colorscheme wrote: »I can't believe are taking this study to heart. You can't compare people who lost extreme amounts of weight in a short amount of time via super unhealthy methods to the general population. Not to mention that it was a sample study of 16 people.
I'm rusty on my statistics, but 16 people for this type of study might very well be statistically significant with a reasonable confidence level.0 -
kportmanshark wrote: »Colorscheme wrote: »I can't believe are taking this study to heart. You can't compare people who lost extreme amounts of weight in a short amount of time via super unhealthy methods to the general population. Not to mention that it was a sample study of 16 people.
I'm rusty on my statistics, but 16 people for this type of study might very well be statistically significant with a reasonable confidence level.
Problem is the averages don't represent any person :-
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kportmanshark wrote: »Colorscheme wrote: »I can't believe are taking this study to heart. You can't compare people who lost extreme amounts of weight in a short amount of time via super unhealthy methods to the general population. Not to mention that it was a sample study of 16 people.
I'm rusty on my statistics, but 16 people for this type of study might very well be statistically significant with a reasonable confidence level.
Effects are statistically significant, not sample sizes. 16 people isn't a sample, it's a collection of case studies. The proof will be in the replication, preferably with larger samples and tighter controls.
Even so, until the research is replicated with something closer to a normal weight-loss population, saying that weight loss slows down your metabolism because the Biggest Loser contestants managed to screw up their metabolisms for life is a lot like saying that jogging half an hour after work will give you the same body as Usain Bolt. Extreme samples are extreme, and their results often don't generalize very well to people who aren't equally extreme.1
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