Obesity is usually the result of overeating, but in a small percentage of people excess weight gain is a symptom of another disease.
Medical causes of obesity can include:
- Hypothyroidism. This is a condition where the thyroid gland, located in the neck, produces too little thyroid hormone. Thyroid hormone regulates our metabolism. So too little hormone slows the metabolism and often causes weight gain.
- Cushing's syndrome. This condition results when the adrenal glands (located on top of each kidney) produce an excess amount of a steroid hormone called cortisol. This leads to a build-up of fat in characteristic sites such as the face, upper back, and abdomen.
- Depression. Some people with depression overeat, which can lead to obesity.