Food and mood often go together. You could grab a comforting bag of chips if you’re feeling down. Or feel so stressed that you can’t even think about food.
It’s normal for difficult emotions to cause you to eat too much or too little. But if you’re living with clinical depression, dietary changes can be long-lasting and lead to drastic weight gain or loss.
The link between depression and weight
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 had a difficult childhood are at higher risk for both obesity and depression.
Things in the environment can also play a role for those living in “food deserts or food swamps,” McIntyre says. Living between fast food chains and convenience stores and far from supermarkets with fresh products makes it more difficult to eat healthy.
The link between depression and weight cuts both ways. People who are depressed are more likely to be obese. And people who are obese are at greater risk for depression.
It’s the classic “chicken-and-egg issue,” says Rodrigo Mansur, MD, a psychiatrist at the University of Toronto. Scientists are still trying to dissect the complex web of factors behind those relationships.
“It’s not that easy when people develop depression, they are less motivated to exercise and they eat more, which makes them gain weight,” says Mansur. “Of course there is a kernel of truth in that. But that’s too much of a simplification of what’s really happening.”
One of the classic symptoms of depression is loss of interest and pleasure in activities. The clinical name for this is anhedonia. Scientists say it’s rooted in the brain’s reward system and once pleasurable activities suddenly seem mundane.
Take food for example. Your mouth detects flavors such as sweetness and satisfying umami. But the pleasure you get from food is processed by your brain. If that reward system goes haywire, it can lead you to forage for more food to make up for the dull or absent pleasure.
“When they ingest food, it doesn’t meet the expected reward,” says McIntyre. This can lead to food addiction, “terrible food cravings that are uncontrollable.”
Depression can also interfere with your impulse control. Studies have shown that people who are depressed are more likely to take risks, such as unsafe sex. Similar cognitive impairments can lead to eating disorders such as binge eating and bulimia.
And the stress hormone cortisol may also play a role as it has been linked to insulin resistance and obesity. In the beginning, stress can dampen your appetite. But prolonged stress can lead to higher insulin levels that lower blood sugar and trigger cravings for sugary and fatty foods.
In rare cases, depressed people may have cognitive distortions or thoughts that alter their worldview in ways that lead to weight changes, says Elizabeth Prince, DO, a psychiatrist at Johns Hopkins University. Prince says she monitors her patients for signs that they’re not intentionally avoiding food because of the belief that “they don’t deserve food,” for example. If so, that’s a sign that their depression has become severe.
Break the link
Your depression symptoms may be very different from someone else’s. So your treatments should be tailored to you.
“There’s not one thing that will always treat depression. It’s really individual 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 problem. approaches, the best is “because they clearly influence each other.”
For McIntyre, the first question is whether his patients sleep well. Sometimes he prescribes medication if he thinks it can help. He also emphasizes the basics of healthy eating. Finally, he urges people to get exercise. In his research, he has shown that people who stay active, even just by going to work, school, or volunteering in the community, achieve much better results with antidepressant treatment.
“We don’t suggest running a marathon, but there should be some activity,” he says.
The fact is that there are no universal rules for treating depression and weight problems. “There is no magic bullet,” says McIntyre. Still, he is hopeful that more research and data in this area will lead to better, evidence-based approaches. “I think the future holds a lot of promise in improving the results.”