WHAT IS OBESITY? Obesity is a condition where excess body fat accumulates to the point that it negatively impacts health. It is measured using: - Body mass index (BMI) - Waist circumference - Body fat percentage. A body mass index of 30 or more is considered obese. How do you get your value? Just divide your weight in kg by your height in meters square. A waist circumference of more than 40 inches in men, or 35 inches in women is considered obese. Finally, a body fat percentage of over 25% in men, and 32% in women is considered excessive.