Inactivity: With a sedentary lifestyle, it’s easy to take in more calories than can be burned off through exercise or normal daily activities.
Unhealthy diet: A diet high in calories, eating fast food, skipping breakfast, consuming high-calorie drinks and eating oversized portions all contribute to weight gain.
Genetics: A person’s genes may affect the amount of body fat stored and where that fat is distributed. Genetics also may play a role in how efficiently the body converts food into energy and how the body burns calories during exercise.
Family history: Obesity tends to run in the family; that's not just because of genetics. Family members tend to have similar eating, lifestyle and activity habits. If one or both parents are obese, a person’s risk of being obese is higher.
Social and economic conditions: Certain social and economic issues may be linked to obesity. For example, not having access to safe exercise areas, being taught unhealthy ways to cook, not having enough money to buy fresh fruits and vegetables or foods that aren't processed and packaged.
People with one or more of these risk factors, can counteract them through diet, physical activity, and behavior changes.