The problem is that body mass index relies on total weight and does not take into account muscle mass or fat deposits. And, because muscle is denser and weighs more than fat, two individuals who weigh the same and are the same height can have the same body mass index but one will have a significantly higher percentage of body fat.
These researchers now know that if most of the fat is in the abdominal area your health risks are greater than if it is in the hips, thighs or rear end. Researchers have discovered that belly fat is metabolically active and can increase the risk of colon cancer by raising certain hormones that affect cell growth. Today, scientists and physicians use a waste to hip ratio which is a measurement of waist size divided by hip size as a more reliable gauge of risk factors. A ratio above 0.85 for women or 0.90 for men is higher than average and typically indicates a greater risk.