Sandra Aamodt - Why Diets Make Us Fat: The Unintended Consequences of Our Obsession With Weight Loss

S everal years ago, my husband and I visited friends who had two teenage daughters. Both girls were smart, beautiful, and well loved, but only one was thin. Her sister had started gaining weight at puberty, and their parents couldnt figure out what to do. Theyd tried talking to her about portion control and exercise. Theyd tried cooking her special food. Nothing slowed her progression from skinny child to voluptuous woman.

Their well-meaning concern was making the situation worse. She was reluctant to sit down for meals with the familyand ate almost nothing when she did. But her father told me that food was disappearing from the refrigerator in the middle of the night, and her weight gain continued. Rather than making her thin, her parents anxiety was pushing her toward an eating disorder and increasing her odds of gaining more weight.

I understood her feelings because I was that teenage girl myself several decades ago, hating myself because I couldnt satisfy my cultures expectations for my body. Because I grew up to be a neuroscientist, I also knew about the biology behind her struggles. Considerable evidence shows that dietingwillfully eating less to lose weightrarely works in the long run, while its unintended side effects do a lot of harm.

When I discovered this evidence, after three decades of losing the same fifteen pounds again and again, it transformed my relationship with food. At first I wasnt sure that changing my approach would work for me, so I tried an experiment. As my New Years resolution in 2010, I vowed to go an entire year without dieting or weighing myself and to exercise every day. I was so pleased with the results that Ive maintained all three habits ever since. My weight used to bounce around a fifty-pound range as I starved or binged my way through the first half of my adult life, but now it remains stable even though I dont worry about calories anymore. And the research suggests that my experience is typical.

If diets worked, wed all be thin by now. Instead we have enlisted hundreds of millions of people into a war we cant win, fighting not against an external enemy but against our own bodies. In the United States, 108 million people went on a diet last yearand half of them were within the normal weight range when they started. Yet research shows that dieters almost always regain their lost weight within a few years, no matter which diet plan they follow. In fact, they often regain more weight than theyve lost. On average, people who go on a diet end up heavier five years later than people of the same initial weight who didnt diet.

Many people are convinced that unless they control their appetite, they will gain weight, get sick, and die young. This common belief gets it backward. Dieting often makes people fatter and less healthy in the long run because it impairs their ability to recognize hunger, which increases vulnerability to emotional eating and food marketing. Research suggests that the resulting cycle of repeatedly losing weight and gaining it back is no better for health than maintaining a higher weight with a healthy lifestyle. Fitness can overcome most of the health risks associated with obesity and also help prevent future weight gain, but only if people dont quit exercising when they discover that it isnt making them lose weight.

By understanding how the brain regulates weight, we can stop struggling to defeat this control system and learn how to let it help us instead. Just as the body needs a certain amount of sleep, the brain has a body weight range that it prefers and will defend for each individual. The brains weight-regulation system will maintain a stable, healthy weight for most people, if it is allowed to do its job without interference. This system mainly operates beneath conscious awareness, influencing hunger and activity in many ways and also changing metabolism by modifying the amount of energy that muscles burn. Lasting weight loss is hard to achieve because when dieting makes a heavy person thinner, the brain responds exactly as it would if a thin person were starving. The result is a powerful mechanism to keep body weight within a certain range.

The belief that dieting will control weight is not only mistaken but also dangerous. I wrote this book because Ive seen too many healthy children turn into diet-obsessed teenagers who are headed for a lifetime of weight cycling and struggles with food. Parents often unwittingly contribute to these problems by hassling kids about their weight or by setting an example of constant anxiety around meals. With the help of a good therapist, our friends daughter found a better way to relate to food. I want us all to do that, for our children and for ourselves.

Our obsession with weight loss hasnt made us thin or healthy, so its time to try another way. If dieting has failed you, thats not because youre a failure but because your brain is working correctly. To find out what to do instead, read on.