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Comment by davnn | Hacker News Reader

I found an article about the "biggest loser study" pretty interesting a few months ago, but didn't investige further.

Tldr: It has to do with resting metabolism, which determines how many calories a person burns when at rest. When the show began, the contestants, though hugely overweight, had normal metabolisms for their size, meaning they were burning a normal number of calories for people of their weight. When it ended, their metabolisms had slowed radically and their bodies were not burning enough calories to maintain their thinner sizes.

First article about the study: http://mobile.nytimes.com/2016/05/02/health/biggest-loser-we...

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Step 1: Go on diet

Step 2: Lose a bunch of weight

Step 3: Go off diet

Step 4: Regain a bunch of weight.

I'm not trying to be a dick, but I don't think there's a lot going on here that doesn't make sense. None of the contestants were particularly thin at the end of the study. Danny Cahill still weighed 191, which is actually pretty significantly overweight for someone not carrying a lot of muscle mass, which he wouldn't be at the end of a 7 month crash diet. If you get your body very very good at using its fat stores you will lower your BMR. The data doesn't suggest this is permanent or significantly impacted Danny's weight gain, the data suggests that Danny Cahill did not stick to the diet.

The Biggest Loser is frequently held up as the gold standard for how not to do things. The weight change is too fast, there is absolutely no support after its over and they frequently optimize for cardio and fat burning over muscle building, which in the short term is effective but in the long term contributes to lowering BMR and making the weight hard to keep off.

But ultimately you have to consider that Danny Cahill was still pretty unhealthy at the end of the show. None of this is starvation mode, in which major parts of your life are hugely effected (ie: you would not have the energy to leave the house).

I'm curious how you rationalize your comments with this:

> What shocked the researchers was what happened next: As the years went by and the numbers on the scale climbed, the contestants’ metabolisms did not recover. They became even slower, and the pounds kept piling on. It was as if their bodies were intensifying their effort to pull the contestants back to their original weight.

> Mr. Cahill was one of the worst off. As he regained more than 100 pounds, his metabolism slowed so much that, just to maintain his current weight of 295 pounds, he now has to eat 800 calories a day less than a typical man his size. Anything more turns to fat.

That does suggest there's something more than just "calories in < calories burned" - that our bodies are willing to adapt to keep metabolic rates low.

At 191 pounds Cahill was still significantly fatter than he should be, and had very minimal muscle mass. We know this is true because it is extremely difficult to not lose muscle on even a small cut, much more so 290lbs over 7 months.

It does not suggest there's something more complicated than calories in < calories burned, it suggests there's something that is causing him to burn fewer calories. My explanation is that Cahill had an inactive lifestyle, poor body composition and was overweight, even after the massive cut. On top of this, no one is claiming he stuck to the diet, so it makes sense he regained the weight.

I'm not disputing that your metabolism can down regulate. I am absolutely disputing that it's a mystery and unfixable. For Cahill he needed to stay on the diet longer, and he needed to build muscle mass.

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