The Complex Link Between Depression and Weight

Medically Reviewed by Michael W. Smith, MD on August 20, 2021
4 min read

Food and mood often go together. You might reach for a comforting bag of chips when you feel down. Or feel so stressed that you can’t even think about eating.

It’s normal for difficult emotions to make you overeat or eat too little. But if you live with clinical depression, changes in eating can be long-term and lead to drastic weight gain or loss.

Weight gain and depression can stem from social, environmental, and biological causes, says Roger McIntyre, MD, a professor of psychiatry and pharmacology at the University of Toronto. For example, people with financial insecurity or who’ve had troubled childhoods are at a higher risk of both obesity and depression.

Things in the environment also can play a role for those who live in “food deserts or food swamps,” McIntyre says. Living amid fast-food joints and convenience stores and far from grocery stores with fresh produce makes it harder to eat healthy.

The depression-weight link cuts both ways. People who are depressed are more likely to be obese. And people with obesity are at higher risk of depression.

It’s the classic “chicken and egg question,” says Rodrigo Mansur, MD, a psychiatrist at the University of Toronto. Scientists are still trying to parse the complex web of factors behind those relationships.

“It's not as simple as people develop depression, they are less motivated to exercise and they eat more, therefore they gain weight,” Mansur says. “There's obviously some truth to that. But that is an oversimplification of what actually happens.”

One of the classic symptoms of depression is the loss of interest and pleasure in activities. The clinical name for this is anhedonia. Scientists say it is rooted in the brain’s reward system and can make once enjoyable activities suddenly seem mundane.

Take food, for example. Your mouth detects tastes such as sweetness and satisfying umami. But the pleasure you get from eating is processed by your brain. If that reward system goes haywire, it can lead you to seek more food in order to make up for the dull or absent pleasure.

“When they ingest food, it doesn’t satisfy the anticipated reward,” McIntyre says. This can lead to food addiction, “terrible cravings for food that are uncontrollable.”

Depression also can interfere with your impulse control. Studies have shown that people who are depressed are more likely to take risks, such as having unsafe sex. Similar cognitive impairments can result in eating disorders like binge eating and bulimia.

And the stress hormone cortisol can also play a role because it is linked to insulin resistance and obesity. At first, stress can dampen your appetite. But long-term stress can lead to higher insulin levels that drive down blood sugar and cause cravings for sugary and fatty foods.

In rare cases, people who are depressed can have cognitive distortions or thoughts that change their worldview in a way that leads to changes in weight, says Elizabeth Prince, DO, a psychiatrist at Johns Hopkins University. Prince says she checks her patients for signs that they aren’t purposely avoiding food because of a belief that “they aren’t deserving of food,” for example. If that is the case, it is a sign their depression has become severe.

Your depression symptoms may be very different from those of someone else. So your treatments should be tailored for you.

“There’s not one thing that will always treat depression. It’s really individualized and something people should work on with their doctor who knows them best,” Prince says. She says a comprehensive treatment plan that addresses both the depression and the weight issue is best “because they clearly impact one another.”

For McIntyre, the first question is whether his patients are sleeping well. He sometimes prescribes medication if he thinks it might help. He also stresses the basics of healthy eating. Finally, he urges people to get some kind of physical activity. In his research, he has shown that people who remain active, even just by going to work, school, or volunteering in the community, have much better outcomes with anti-depression treatment.

“We are not suggesting running a marathon, but there has to be some activity,” he says.

The fact is that there are no universal rules for treating depression and weight issues. “There is no silver bullet,” McIntyre says. Still, he’s is hopeful that more research and data in this area will lead to better, evidence-based approaches. ”I think the future holds a ton of promise in improving outcomes.”