Your waist measurement is the best indicator of problem fat. Dr Susan Jebb, head of nutrition and health at the MRC Human Nutrition Research Unit in Cambridge, recently pointed out to a conference of healthcare workers in London that many of the dangers of obesity are often associated with excess fat, and therefore cannot be evaluated by measuring only the patient's weight. An example being if a person trains heavily and holds a substantial amount of muscle, it will throw off all the weight versus height charts, making them useless. It is common for a bodybuilder or serious gym user when measured at a standard insurance or GP check up, to be ticked as obese, yet amusingly when they lift their t-shirt up, they show a perfect set of abs!
Researchers explain that intra-abdominal (belly) fat produces hormones that affect the metabolism. If these hormones are produced in excess they directly or indirectly alter the insulin resistance of the body's tissues. They say that whatever her build, a woman should have a waist measurement of under 35″ and preferably under 32″. Men should have a waist measurement of less than 40″ and preferably under 38″. If not fat levels can increase substantially and the risk of diabetes can increase considerably.
Apparently GPs are reluctant to measure waists lest their patients are embarrassed and they find it time consuming. Doctors say they could use the Tanita body composition scales that measure body fat levels, via electrical impedance levels through the feet, which is now a fairly accurate method at determining bodyfat % levels. This will allow doctors to clearly know how much of their patients weight is fat or muscle and what risks they are facing and what actions are required.