jimmy bell, a neuro imageer at cambridge, university of college london calls it tofi, t-o-f-i. the outside, fat on the inside. when you do mris inside, you can actually see the fat in all of the organs. the muscle, the heart, et cetera. bottom line is, from your weight, you can't tell where you are. >> so how -- so what do you do? how can you tell, first of all? >> well, in fact, the best way is, again, waist circumference. that's the cheapest way. there are some lab tests your doctor can do, a fasting insulin and some liver function tests that can give you clues as to whether or not there is a problem or not. but the single best way to deal with excess fat is to get it off and the easiest way to do that is to exercise. the problem with exercise is, every doctor will tell you, if you exercise, you would lose weight. that's because they say a calorie is a calorie. so if you burn them off, you would lose weight. guess what, there is not one scientific study, not one literature reference that you can point to that says that exercise causes weight loss. what it does is, it causes m