Because cortisol stimulates insulin release to maintain blood sugar levels, it can also lead to sugar cravings and an increased appetite in general. Giving in to those cravings can lead to weight gain.
Research shows that overweight individuals tend to have a higher cortisol response to stress, says Vidhya Illuri, MD, an endocrinologist in Texas. Cortisol not only makes you hungry, but it can also slow down your metabolism. After measuring metabolic rates, a study in the journal Biological Psychiatry found that women who reported experiencing one or more stressful periods the previous day burned fewer calories than those who didn't.
Cortisol can also reduce lean muscle mass, according to a study published in The Journal of Clinical Endocrinology & Metabolism. Muscle burns fuel faster than fat, meaning it can burn more calories. So when your body is stressed, it tries to hold onto fat instead, so it can provide more energy. This decrease in muscle mass can also make it more difficult to control your weight.