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.

CAUSES

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)

Certain medical conditions may also lead to weight gain. These include:

• Polycystic Ovary Syndrome(PCOS): a condition that causes an imbalance of female reproductive hormones
• Prader-Willi syndrome: a rare condition that an individual is born with which causes excessive hunger
• Cushing syndrome: a condition caused by having an excessive amount of the hormone cortisol in your system
• Hypothyroidism(underactive thyroid): a condition in which the thyroid gland doesn’t produce enough of certain important hormones
• Osteoarthritis (and other conditions that cause pain that may lead to inactivity).