With the new year upon us, many people are resolving that this will be the year they lose a lot of weight and keep it off. I hate to burst their bubble, but it won’t be. The evidence is utterly clear: People take off weight in the short run, but for the majority of dieters nearly all of it comes back within a couple of years. The weight regain is a predictable biological response to dieting.
When your body detects calorie deprivation, such as when you diet, it makes multiple changes that keep you from starving to death, but that make it all too easy for lost weight to return. Hormone changes make dieters more likely to feel hungry and less likely to feel full, and metabolic changes help the body function on fewer calories, leaving more to store as fat.
To make matters worse, in a cruel Catch-22, brain imaging studies show that food is especially tempting when you’ve been depriving yourself of it. Research by Eric Stice and his colleagues found that when they were shown pictures of high calorie foods, dieters had increased activation in brain regions associated with craving those foods and with noticing and paying attention to them. The longer you deprive yourself, the more appetizing and tougher to resist the foods get. In sum, dieting and losing weight cause biological changes that make it extremely difficult to continue taking weight off, and too easy for lost weight to return.
If you regain weight under those nearly insurmountable new circumstances, it’s not because you have a weaker will than other people. In fact, contrary to what most people assume, willpower is not highly correlated with weight. Denise de Ridder at the University of Utrecht reviewed 50 studies that looked at the relationship between willpower and a range of different outcomes. She found that willpower was more important in domains like school achievement and work success than in body weight. Similarly, consider research on the ability to delay gratification, in which researchers measure how long a child can resist one marshmallow after being told they can have two marshmallows if they hold out long enough. The longer the child can resist the marshmallow at age 4 the higher their SAT scores and the better their emotional resilience years later. But this willpower is only weakly related to their body weight.
You may think of this as bad news (“I’m unlikely to keep weight off”) or good news (“At least it’s not my fault when I regain weight”), but either way, it’s clear that weight loss is not a worthwhile goal. Luckily, there is a more worthwhile goal to strive for, and it has the added benefit of being quite a bit easier to achieve than weight loss. That goal is improved health. And you don’t have to lose weight to do it.
There is ample research showing that it is possible to be healthy and obese, and there are nearly 20 million metabolically healthy obese individuals living in the United States. According to a nationally representative sample of more than 10,000 individuals who were studied for an average of 14 years, there were no mortality differences between obese, overweight and normal weight individuals if they regularly engaged in two or more of these four healthy behaviors: eating at least five servings of fruits and vegetables daily, exercising more than 12 times per month, consuming alcohol in moderation (or less), and refraining from smoking. And the more of these behaviors you did, the longer your lifespan, again regardless of your weight.
This means that everyone can benefit from engaging in healthy behaviors (including people who are not overweight or obese). So instead of making this yet another year in which you resolve to lose weight and keep it off, let this be the year you get healthy instead. It’s a lot easier.
Dr. Traci Mann is the author of "Secrets from the Eating Lab: The Science of Weight Loss, the Myth of Willpower, and Why You Should Never Diet Again."