It’s often treated as a personal failure when people regain weight after a diet. We’ve written several blogs about how hard it is to keep pounds off and how people shouldn’t beat themselves up. Weight concerns are not a moral or personal failing, as many portray them as being. A new study may help reframe how we view weight loss and gain.
“The belief that weight gain can be solved simply by ‘just eating less, exercising more, and if you don’t do that, it’s a lack of willpower’ is so simplistic and so untrue,” said lead study author Dr. Mireille Serlie, professor of endocrinology at Yale School of Medicine. “I think it’s important for people who are struggling with obesity to know that a malfunctioning brain may be the reason they wrestle with food intake. And hopefully this information will increase empathy for that struggle.”
Dr. Serlie and her colleagues performed a rigorous and comprehensive study. They found that obesity diminishes the brain’s ability to feel full and satisfied after eating fat or sugar. Even if people lost a significant amount of weight, their brains didn’t regain the ability to recognize cues to stop eating.
“This study captures why obesity is a disease — there are actual changes to the brain,” said Dr. Caroline Apovian, a professor of medicine at Harvard Medical School.
In the study, 30 people who were medically obese and 30 who had a lower weight were fed via a feeding tube. Researchers wanted to ensure that visuals, smells or food tastes didn’t impact participants’ perceptions. The researchers used MRIs to look at the participants’ brains. They saw that the brain registered as eating and dopamine levels rose, and the reward centers were activated in people with lower body weight after being fed with a tube. However, people who were medically obese didn’t have the same reactions. Not only did they not recognize being fed, but they craved fat, yet their brains didn’t recognize it.
“This was surprising,” said Dr. Serlie. “We thought there would be different responses between lean people and people with obesity, but we didn’t expect this lack of changes in brain activity in people with obesity.”
“In my clinic, when I see people with obesity, they often tell me, ‘I ate dinner. I know I did. But it doesn’t feel like it,’” said Dr. Serlie. “And I think that’s part of this defective nutrient sensing. This may be why people overeat despite the fact that they’ve consumed enough calories.”
“We need to find where that point is when the brain starts to lose its capacity to regulate food intake and what determines that switch,” Dr. Serlie said. “Because if you know when and how it happens, you might be able to prevent it.”
The future steps of this research could change how we approach weight management. We all know it’s hard to keep off weight, especially if you lose a large percentage of your body weight. This research shows that regaining it isn’t simply a matter of willpower; your brain can work against you. In the future, there will hopefully be more tools to help people sustain the results of all their hard work.
