Obesity means having too much body fat. It is different from being overweight, which means weighing too much. The weight may come from muscle, bone, fat, and/or body water. Both terms mean that a person’s weight is greater than what’s considered healthy for his or her height.
Obesity happens over time when you eat more calories than you use. The balance between calories-in and calories-out differs for each person. Factors that might affect your weight include your genetic makeup, overeating, eating high-fat foods, and not being physically active. Obesity increases your risk of diabetes, heart disease, stroke, arthritis, and some cancers.
Common specific causes of obesity include:
- Eating a poor diet of foods high in fats and calories
- Having a sedentary (inactive) lifestyle
- Not sleeping enough, which can lead to hormonal changes that make you feel hungrier and crave certain high-calorie foods
- Genetics, which can affect how your body processes food into energy and how fat is stored
- Growing older, which can lead to less muscle mass and a slower metabolic rate, making it easier to gain weight
- Pregnancy (weight gained during pregnancy can be difficult to lose and may eventually lead to obesity)