Obesity is defined as being extremely overweight due to consuming more calories than the body needs. Anyone can become obese at any age if they eat more calories than they burn each day, causing the excess calories to be stored as fat. Obesity risk increases most between ages 20 to 55, and it can be treated by slowly losing one to two pounds per week through a healthy diet that focuses on balance and moderation across all major food groups and cuts daily calorie intake by 500 to 1000 calories for adults.