Health

Dieting, and How Your Body Forces You to Regain the Weight

Thursday May 12, 2016

The New York Times has been on a tear recently, publishing a series of articles over the past couple weeks all about dieting and exercise, and how the two intersect. The series, taken together, has painted a fascinating portrait of how we’re getting it all wrong when it comes to dieting or “cleanses.”

First up, a study of the men and women who starred in “The Biggest Loser”, NBC’s mesmerizing reality series that showed people lose hundreds of pounds in a matter of months. Contestants from Season 8 (filmed 6 years ago) went to the National Institute of Health for three days of testing. Now, not surprisingly, many of them regained some or all of the weight. But, the study delved deeper to try to figure out WHY they regained weight. What they found should be a warning call to anyone thinking about losing weight through restricting calories.

It turns out, their bodies actually burn fewer calories per day than before they lost weight, sometimes to the tune of 500 calories less per day (that’s an entire meal) than before they went on the diet. It’s like the body is purposefully holding on to calories. So, now the men and women who appeared on the show have to maintain a daily calorie intake that is actually quite low. (Men are supposed to eat roughly 2,500 calories per day; women, 2,000 calories.) They have to eat substantially less per day than you, for the rest of their lives, just to stay at their current weight. Their metabolisms haven’t seemed to recover at all from the diet they went through on the show.

 

But, the whammy is that at the same time that was happening, their leptin hormone level also plummeted; actually, by the end of the show, some of them didn’t have any leptin left. Leptin, and the lack of it, can trigger feelings of intense hunger and craving. Basically, the people who had been on “The Biggest Loser” now felt hungry all the time, even if they were eating a 2,000 calorie diet, due to the lack of leptin and other hormones related to feeling satiated.

This combined reaction to calorie restricting diets is actually a matter of neuroscience. In a follow-up piece, Sandra Aamodt, a neuroscientist, explained how our bodies have a “set point,” or a weight range. If we veer from it, our bodies (through the metabolic changes and hormone changes explained above) fight back to re-gain the weight to get us back to our set point. In a study of twins (so, genetically similar people), a study showed that a single diet increased the odds of one twin becoming overweight by 2 (for men) or 3 (for women) times. If one of the female twins went on 2 or 3 diets, she was five times as likely to become overweight. The dieting twin were more likely to gain weight than their non-dieting twin sibling.

So, that’s depressing. Basically, trying to lose weight is exactly what will make you gain weight.

Which brings us to another article about the intersection of exercise, calorie restrictions, and obesity. In this study, mice prone to obesity were separated into three groups: a control, an exercising group, and a diet-restricted group. The exercising group had access to a running loop and unlimited food. The diet-restricted group were given 20% less than what the exericing group ate.

At the end of the study period, the exercising group and diet-restricted group had managed to avoid obesity (the control group had become obese). BUT, (big but) the exercising group literally had different gut-bacteria in their bodies (even though they’d all eaten the same food), associated with long-term leanness. They also had a higher metabolic rate than the diet-restricted group.

Granted, of course, these were lab rats and not sophisticated-minded human beings. But, taken with the studies on humans above, it all seems to point the way to calorie-restricting being a temporary fix that potentially creates unavoidable, long-term weight problems.

This is a good reminder that next time you get the urge to diet, it may be a better idea to keep eating and figure out a way to exercise more.

 

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