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Diet

Is Your Diet Making You Fat?

Lessons from the FinnTwin study.

It is hard to turn on the television or read the newspaper these days without being bombarded with coverage of the obesity epidemic and ideas for weight loss. The Biggest Loser, Extreme Make Over Weight Loss Edition, The Weight of the Nation, Mayor Bloomberg’s ban on supersize sodas, and “slim down for summer” segments on the morning news programs tell us why and how to shed the pounds. Images of headless obese men and women, sloppily dressed in too-tight clothing and gorging themselves on junk food conjure feelings of disgust and thoughts like “I don’t want to look like that! I should go on a diet.” And there is a multi-billion dollar a year industry that would be happy to help you do so. However, recent research suggests that going on a diet may only add to your weight woes.

Published this year in the International Journal of Obesity, researchers in Finland studied identical twins in which one twin had a history of dieting and the other twin had never been on a diet. Confirming previous studies, this research found that a history of dieting was positively associated with weight gain; the more dieting episodes a person had the more weight they gained. One possible explanation for this finding may be that people who are genetically prone to obesity are exactly those most likely to both diet and to gain weight. So it’s not the diet that’s making you fat, it’s the genes. This study put that argument to rest. Remember, they studied identical twins, which means that they share the same genetic make-up. The researchers found that the twin with a history of dieting was heavier than the non-dieting twin. Participants were first assessed when they were 16 years old and both twins had similar weights. However, by the time that the twins were 25 years old, the dieting twin was significantly heavier than the non-dieting twin. They were only about three lbs heavier but, with all of that dieting, common wisdom would say that the dieting twin should be thinner than the non-dieting twin. The results of this study suggest a causal relationship between dieting and weight gain. In other words: Yes, your diet is making you fat (or at least fatter).

There are many factors that contribute to this finding. I believe that one of the most important is the disconnection between eating and our body’s natural signals of hunger, fullness, and satiety that develops through dieting. We learn to ignore our body’s needs in favor of an “eat this-not that” mentality in which certain foods are off-limits while we try to trick ourselves into feeling full with diet alternatives made with ingredients that I cannot pronounce that are rarely satisfying and often lead to feelings of deprivation. Feelings of deprivation and restriction may in turn lead to overeating. This pattern of restriction and overeating leads to weight cycling (weight loss followed by gain, over and over again) with serious physical and emotional consequences.

This is not to say that a sustainable healthy diet and lifestyle is not beneficial for the body and the mind. The study also found that physical activity was related to increased weight control and that lifestyle modifications involving exercise may be successful at preventing weight regain. Mindful eating can also help you get off the weight rollercoaster. So next time you are pondering Atkins vs. Dukan to get your body “bikini-ready” this summer, I hope that you will consider all of the costs of a diet.

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