Obesity is diagnosed by calculating your BMI. BMI is based on your height and weight. A BMI of 30 or more defines obesity. In general, this means your body weight is 35% to 40% more than your ideal body weight.
Your body fat also can be calculated by using skin calipers. Calipers are an instrument that measures the thickness of your skin.
Body shape is also important. People who carry most of their weight around the waist (apple shaped) have a greater risk of heart disease and diabetes than do people with big hips and thighs (pear shaped).
Waist circumference is a good measure of abdominal obesity. Women with a waist more than 35 inches or men with a waist more than 40 inches are at increased risk.