James Krieger on the Biggest Loser study that's going around
SideSteel
Posts: 11,068 Member
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.
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.
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Replies
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@ninerbuff just tagging you since you posted about this -- didn't read your post yet but I thought this would interest you.0
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Thanks brother!
A.C.E. Certified Personal and Group Fitness Trainer
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Been in fitness for 30 years and have studied kinesiology and nutrition
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BOOM! Thank you for sharing this.0
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Always nice to see sensibility coming to the forefront2
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Game. Set. Match.1
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Thank you so so much for posting. Really helps calm my anxieties
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Love this. But still sad we're going to have to argue about this study for years to come on the forums. This stuff, like starvation mode, simply will. not. die.12
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I'm feeling slow today and need this translated. Is he saying that the contestants accidentally threw off the results because they knew they were going to be analyzed?2
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Carbsane ? Welcome to the asylum.
I noticed the TDEE at yr 6 was over 3000 and that the RMR was pretty close to what Katch-McArdle predicts in any case.
Hall's methodology of doing his own regression analysis of RMR at baseline on study participants and using that to identify deviation is a bit feeble IMO.2 -
Thanks for this
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Here's the weight measurements referred to in the OP :-
This data is for Baseline, end of competition and 6 year follow up resp :-
High TDEE and exercise level sustained by the looks of it. Or wound up for the 6-y review ??0 -
I am by no means a researcher. However I am currently enrolled in a class where we learn more about how to examine conclusions presented from research projects involving animal behavior. It has given me better understanding about how often we accept findings without actually looking at the methods used and how the results are then interpreted to prove or disprove a theory. I would love to read the entire paper on this.0
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Thanks Yarwell. I am attempting to apply what I am learning.0
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thanks a lot. Bookmarking this.0
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Thank you SS. Very interesting.0
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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.
I think this is a reasonable viewpoint although I am not entirely convinced by Mr Krieger's reasoning (in the absence of further information which would be nice so I can consider the issues in my own mind)
The point re: weight stability is in line with what I have read in the past (possibly in articles by James Krieger himself) in that a tighter control of weight prior to RMR assessment with a variation of no more than about 10g - 15g a day would have been better. If it is correct that the participants were showing a variation of about 30g a day (based on the fact they were seemingly losing about 0.5lbs or so a week and therefore in a calorie deficit) that is something to be factored in.
So, if we accept they were not weight stable how much would this throw off the magnitude of any anticipated fall in RMR or does it negate any results? The study indicates that, on average, there was a suppression of about 500 cals per day. While that number may not be reliable what order of discount to it could be reasonably applied (if that is indeed even valid?) Even if we reduce that figure by 40% that still leaves a greater than anticipated fall of 300 cals per day.
In addition, it seems that the participants were still engaging in high levels of physical activity and I think it is right that generally a fall in activity shows the bigger adaptation and is therefore more of a concern than RMR. So it could be that the participants were purposefully exercising because they knew the review was coming up. However, it is not planned exercise which normally takes a hit in these circumstances but rather unconscious / unplanned activity (NEAT / SPA). Do we know if this was adjusted for and if so if there was a fall in this area specifically? It seems to me that participants may have maintained a high level of exercise anyway following the show because it had become their reality that this was critical in them keeping weight gain to a minimum or keeping weight stable (which was made more necessary given they had a larger than anticipated reduction in RMR and/or NEAT /SPA to contend with.)
If we assume that their was a lowering of RMR by about 300 cals per day as discussed above that is not insignificant. Many people experience creeping weight gain on lesser figures and a constant theme of discussion on MFP is how diet / CI is the primary driver of weight loss rather than activity / exercise. This could then be compounded by a concurrent fall in NEAT / SPA. Sounds sucky to me.
So more constant dietary vigilance with the need to engage in higher than normally required levels of planned exercise could be the result of being a Biggest Loser contestant. Call me old fashioned but suffering for the sake of it doesn't sound like a great gig and making things easier for myself over the long term, rather than harder, makes more sense. If that means avoiding extreme methods then sign me up
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^ Thanks msf74 -- I obviously couldn't quantify that hypothetical but I'll see what James might speculate.0
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^ Thanks msf74 -- I obviously couldn't quantify that hypothetical but I'll see what James might speculate.
Ta. I've read a few of his articles and he seems like a good source of reference.
Obviously there's no point in being alarmist if the science does not support it. That said, I think it's better to stack as many chips in your favour for long term maintenance as you can and if Biggest Loser style protocols are contrary to that to a meaningful degree and that is borne out effectively by this recent study then I would like to know.0 -
^ Thanks msf74 -- I obviously couldn't quantify that hypothetical but I'll see what James might speculate.
Ta. I've read a few of his articles and he seems like a good source of reference.
Obviously there's no point in being alarmist if the science does not support it. That said, I think it's better to stack as many chips in your favour for long term maintenance as you can and if Biggest Loser style protocols are contrary to that to a meaningful degree and that is borne out effectively by this recent study then I would like to know.
I think we can both agree that Biggest Loser style protocols are impressively stupid regardless of this study
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^ Thanks msf74 -- I obviously couldn't quantify that hypothetical but I'll see what James might speculate.
Ta. I've read a few of his articles and he seems like a good source of reference.
Obviously there's no point in being alarmist if the science does not support it. That said, I think it's better to stack as many chips in your favour for long term maintenance as you can and if Biggest Loser style protocols are contrary to that to a meaningful degree and that is borne out effectively by this recent study then I would like to know.
I think we can both agree that Biggest Loser style protocols are impressively stupid regardless of this study
Lulz - it's like you're reading my mind or something!2 -
I'm a skeptic of the study also, but it brings some interesting topics up.
Lost me here a bit. Isn't RMR related to TDEE? Excuse my naiveté but I thought RMR was a major determining factor of TDEE?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]
In the Danny Cahill example noted in the NYT, they said he burns 800kcal less per day than expected per that study. So I interpret that as if he has a TDEE of 2000kcal, he now has a TDEE of only 1200kcal. (http://www.nytimes.com/2016/05/02/health/biggest-loser-weight-loss.html)
This doesn't quite pass the sniff test for me, because if he really was at a 800kcal disadvantage he'd actually gain way more weight (almost 7-lbs a month right off the bat) if he was targeting the "correct" TDEE for maintaining..
*EDIT*
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?0 -
No amount of weight loss, at any speed, will ever allow you to thereafter eat a surplus of calories without gaining weight. What's the big deal?0
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CoffeeNCardio wrote: »Love this. But still sad we're going to have to argue about this study for years to come on the forums. This stuff, like starvation mode, simply will. not. die.
Remember the doctor that said vaccines cause autism? even though he lost his license and rescinded the paper, people still believe it. It won't ever die, like the starvation mode myth.10 -
JeromeBarry1 wrote: »No amount of weight loss, at any speed, will ever allow you to thereafter eat a surplus of calories without gaining weight. What's the big deal?
The big deal is that this study concludes that after you've been fat, your baseline metabolic rate will slow once you've gotten thin again, and that your hunger hormones and chemicals will be elevated - making it much harder to keep the weight off. They said that for one guy his TDEE would be 800 calories lower than someone who had never been fat.
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kportmanshark wrote: »JeromeBarry1 wrote: »No amount of weight loss, at any speed, will ever allow you to thereafter eat a surplus of calories without gaining weight. What's the big deal?
The big deal is that this study concludes that after you've been fat, your baseline metabolic rate will slow once you've gotten thin again, and that your hunger hormones and chemicals will be elevated - making it much harder to keep the weight off. They said that for one guy his TDEE would be 800 calories lower than someone who had never been fat.
This is not the only study to show this, but the magnitude of change in the study is quite high.
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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).1 -
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.0 -
Additionally, I'm not saying "disregard the study", I'm saying that I question its relevance to the vast majority of people.0
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