Over 70 percent of American adults are overweight or obese, and dieting to shed the extra pounds isn’t always easy. But a recent study suggests that eating healthy isn’t just a matter of will power. Some of us might actually be wired to want higher-calorie foods.
Scientists scanned the brains of 36 teenagers at various weights while showing them words written on a black chalkboard. Some of the words were high-calorie foods such as “frosted cupcakes,” “garlic bread,” and “chicken wings.” Others were lower-calorie alternatives — think “white peach” and “pickled beets.” To be sure of their results, scientists also showed participants non-food words such as “permanent marker.” Then they monitored what teens ate at a buffet afterwards.
They were particularly interested in the brains of high-risk participants — those who were at a healthy weight but had obese mothers.
“If you have an overweight mother, you’re more likely to become obese,” said Susan Carnell, the study’s author and an assistant professor at Johns Hopkins University’s Department of Psychiatry and Behavioral Sciences. “We were trying to see if there’s something different about the brain in students with a high risk of becoming obese later in life.”
Carnell found that self-regulatory circuitry in the brains of high-risk teens was less responsive than in other participants with a healthy weight. This region of the brain basically affects our resistance to impulsive behavior, such as how well we anticipate the consequences of scarfing down an extra cookie at lunch.
“It’s kind of surprising to me that not everyone is obese in the environment we live in with highly palatable, high-calorie foods,” Carnell said. “What seems to distinguish people is the ability to make a conscious decision about whether to eat this or not — to engage in a self-regulation mechanism of the brain.”
Though high-risk study participants also ate more calorie-dense foods at the buffet afterwards, there’s no telling if they’ll actually become overweight. However, Carnell did notice that this region of the brain was less responsive in obese teens, too. The results may explain why some people struggle to avoid cheeseburgers, while others can’t seem to get off the high of a 30-day cleanse.
“This study really adds to the consistent and growing evidence of altered brain activity [affecting obesity],” said Cary Savage, a senior scientist at the Banner Alzheimer’s Institute, who studies obesity.
But this study doesn’t mean that people should ponder whether or not they have “dysfunctional brains,” Savage said. “It’s not just simple diets, eating less and exercising more. It’s also really doing things to help people with self-regulation.”
Kelly Kasulis is a freelance journalist. Follow her on Twitter: @KasulisK.