Bad News: Diets Don't Work

For the first time in their lives, some people are hearing it just this year, in 2019: diets don’t work. They don’t. Diets do not result in a long-term change in weight. The only way a diet is ‘successful’ is if it doesn’t change.

Sandra Aamodt outlines the research and biology behind the failure of diets in her book Why Diets Make Us Fat, which I’d recommend to anyone who has ever been on a diet, but because life is busy, I read the book for you. For a flash overview of her work, Aamodt has a TED talk.

Why Diets Don't Work

The first concept of importance for why diets don’t work is the set point. Biologically, the body has a range of ten to fifteen pounds that it identifies as our weight. This is called the defended range because the body will see deviations from this weight as an unwanted change.

In the past, when food was scarce, this system allowed for the body to recognize when starvation was occurring and to adjust the function of the body to keep weight on in times of limited food. Now, however, it means that deviations from that set weight range from dieting are defended against. The body will do all it can to keep us from losing that weight.

What’s Even Worse

Beyond not overcoming the body’s set point regulation, diets have the opposite effect to their intentions. In the long-term, dieting is linked to higher weight and more psychological disorders or strain related to food.

Aamodt lays out study after study in her work, each one adding to the pile of evidence in a way that a brief article simply cannot, but in short, diets lead to an obsession to food that leads to binge eating (the brain’s response to a period of starvation). Studies have found even over generations from grandparents to their grandchildren that diets and starvation lead to weight gain (or a larger weight overall) as the body adjusts to an environment it assumes has limited food.

Why then?

If diets fail, why have we been hearing about them and doing them and being prescribed them for our entire lives? To be blunt, our culture.

Self-hatred and external judgement run rampant in the United States (and other countries, too!) and higher weights are often connected to moral judgements about character despite the near impossibility of controlling weight with willpower alone (because diets don’t work). Weight bias has been found in hiring, dating and medical treatment. That discrimination then leads to stress that has been found linked to higher rates of binge eating and rates of obesity later in life.

However, the diet industry makes a lot of money on that insecurity. In fact, for the diet industry, a cycle of failed diets that have people returning to the same companies to help them “lose weight” again after they gain it back is the perfect situation. Repeat customers fuel companies who sell weight-loss related products.

Science doesn’t support diets, but dieters are a rich population to profit from. If we all stopped dieting, they’d be out of business—which sounds great to me.