Chronic stress makes the mind desire for comfort food

Chronic stress can suppress the body’s natural satiety signals and affect the mind, increasing appetite and cravings for sweets.

Chronic stress suppresses the brain’s satiety signals, leading to constant reward signals for more appetizing food.

This happens in an area of the brain known as the lateral habenula, which normally blocks these reward impulses when the mind is active.

Professor Herzog, the study’s principal author and visiting scientist at the Garvan Institute, comments, “Our findings reveal that stress can override the brain’s natural response; therefore, it affects the mind and diminishes pleasure from eating — meaning the brain continuously rewards eating.”

“We showed that chronic stress, combined with a high-calorie diet, can drive more and more food intake as well as a preference for sweet, highly palatable food, thereby promoting weight gain and obesity. This research highlights how crucial a healthy diet is during times of stress.

From mental stress to weight gain:

While some people choose to eat less than usual during stressful times, most people choose calorie-dense, high-sugar, and fatty foods.

To understand what drives these eating behaviours, the team examined how different brain regions responded to long-term stress under varying diets in mouse models.

“We found that the lateral habenula, which usually regulates reward response, was active in mice on a short-term, high-fat diet. However, chronic stress silences this brain part, keeping reward signals active and overriding satiety signals, encouraging pleasure-driven feeding,” explains Dr. Ip.

“We found that stressed mice on a high-fat diet gained twice as much weight as mice on the same diet that were not stressed.”

Researchers found that NPY, a chemical produced by the brain in response to stress, primarily causes weight gain.

“Mice on a high-fat diet gained less weight and ate fewer comfort foods when NPY was blocked.”

In a “sucralose preference test,” mice chose between plain water and artificially sweetened water.

“Stressed mice on a high-fat diet consumed three times more sucralose, indicating stress drives sweet cravings,” says Professor Herzog.

“Crucially, we did not see this preference for sweetened water in stressed mice that were on a regular diet.”

Chronic Stress Outweighs a Balanced, Healthy Energy Level and Affects the Mind

“In stressful situations, using energy and seeking reward can calm you, making a food boost useful for relief.” “But long-term stress alters the equation, leading to unhealthy eating habits detrimental to the body,” says Professor Herzog.

The study finds stress can override the brain’s ability to balance energy needs and regulate eating habits. Consequently, it disrupts normal eating patterns and increases cravings.

“This research emphasises just how much stress can compromise a healthy energy metabolism,” says Professor Herzog. “It’s a reminder to avoid stress and, if facing long-term stress, eat healthily and keep junk food away.”