Researchers have found (Neuron) that stress can override the brain’s natural response to satiety, leading to non-stop reward signals that promote eating more highly palatable food. This occurred in a part of the brain called the lateral habenula, which when activated usually dampens these reward signals. While some people eat less during times of stress, most will eat more than usual and choose calorie-rich options high in sugar and fat. To understand what drives these eating habits, the researchers investigated in mouse models how different areas in the brain responded to chronic stress under various diets.
According to Dr Kenny Chi Kin Ip from the Garvan Institute, an area known as the lateral habenula, which is normally involved in switching off the brain’s reward response, was active in mice on a short-term, high-fat diet to protect the animal from overeating. However, when mice were chronically stressed, this part of the brain remained silent. This allowing the reward signals to stay active and encourage feeding for pleasure, no longer responding to satiety regulatory signals, says a release.
