Causes of Obesity
Medications That "Cause" ObesityCertain drugs, such as steroids, some antidepressants, and some medications for psychiatric conditions or seizure disorders, may also cause weight gain. These drugs can slow down the rate at which the body can stimulate appetite and burn calories, and can cause the body to hold on to extra water.
Other "Causes" of ObesityA lack of sleep may also contribute to obesity. Recent studies suggest that people with sleep problems may gain weight over time. On the other hand, obesity may contribute to sleep problems due to medical conditions. For example, a person who has sleep apnea briefly stops breathing multiple times during the night (see Health Effects of Obesity).
A Summary of the Causes of ObesityThere are a number of factors that increase a person's chances for developing obesity, including genetic, environmental, and social factors, as well as certain medical conditions and medications. Some people may consider these obesity risk factors to be "causes of obesity," but they are not, because they do not "guarantee" obesity. In all of these cases, the underlying cause of obesity is eating more calories than the body can burn -- for whatever reason.
If you are overweight or obese (see Calculate BMI), the good news is that you can do something about it. The first step is understanding the obesity risk factors that apply to you. The next step is starting the process of consuming fewer calories than you burn (see Obesity Prevention for more information on how to do this).