Cortisol is a hormone made by the two adrenal glands: there’s one at the top of each kidney. This hormone is important in activating the immune system and processing carbohydrates. High amounts of cortisol are released in moments of stress — thus, the nickname “the stress hormone” — but unhealthy lifestyle habits, like alcohol consumption, too little sleep, and a high glycemic diet, are some of the other primary drivers of harmfully high cortisol levels.

When you have too much cortisol in your body over a long period, a disorder called Cushing’s syndrome can occur. Additionally, chronically elevated cortisol levels also promote overeating and weight gain.

On the other hand, when the adrenal glands aren’t making enough cortisol and other hormones, people can develop adrenal insufficiency or Addison’s disease.