Uncommonly, weight gain is caused by one of the following disorders: Brain damage caused by a tumor (especially a craniopharyngioma) or an infection (particularly those affecting the hypothalamus), which can stimulate consumption of excess calories Hyperinsulinism due to pancreatic tumors Hypercortisolism due to Cushing syndrome, which causes predominantly abdominal obesity Hypothyroidism (rarely a cause of substantial weight gain) Eating disorders At least 2 pathologic eating patterns may be associated with obesity: Binge eating disorder is consumption of large amounts of food quickly with a subjective sense of loss of control during the binge and distress after it.