Research has pinpointed the stress steroid cortisol as the key adrenal culprit behind belly fat:
It keeps both insulin and blood sugar levels high that’s bad news since insulin fosters the storage of excess blood sugars as fat, particularly in the belly. “And because fat cells in the belly are especially high in receptors for both cortisol and insulin, repeated stress insults add to fat storage in this region.
What’s more, cortisol breaks down lean muscle (the very type of tissue that burns calories most efficiently) and spikes appetite for several hours after other stress effects subside.
Originally, cortisol induced hunger helped the body replace the energy it used up when running from a stressor like a tiger. We don’t literally run from stressors anymore, yet cortisol still produces that hunger and we gain weight.
In fact, a study at the University of California at San Francisco found that when women were subjected to a stressful situation, then left in a room with free access to food, they consumed 57 percent more calories in the half hour afterward compared with their less-stressed peers.