Obesity is the accumulation of excessive body fat. A distinction is made between being overweight and being obese through the determination of the Body Mass Index (BMI). BMI is weight in kilograms divided by height in meters squared. People having a BMI of 25 to 29.9 are considered overweight while those with a BMI of 30 or more are considered obese.The percentage of fat and muscle in the body or the body composition is also considered when defining obesity. Women who have more than 30% body fat or men who have more than 25% body fat are considered obese. Thus, a body builder who may have high BMI but is very muscular and has low body fat is not categorized as obese.The waist measurement can also help in determining whether a person is obese or not. Women whose waists measure 35 inches or more and men whose waists measure 40 inches or more are generally considered obese. The measurement in the stomach region is specifically related to health risks associated with abdominal fat such as Type 2 diabetes, hypertension and cardiovascular disease.