Thin on the outside can hide a big problem

I have talked about being TOFI (thin outside, fat inside) before, but it is back in the news more than ever right now.
New research has found that people who maintain their weight through diet rather than exercise are likely to have major deposits of internal fat, even if they are otherwise slim.
They eat too many fatty, sugary foods — and exercise too little to work it off — but they are not eating enough to actually be fat. Scientists believe we naturally accumulate fat around the belly first, but at some point, the body may start storing it elsewhere.
There is an increased risk of heart disease and Type 2 diabetes with anyone who has increased fat, no matter where it is. This means that normal-weight persons who are sedentary and unfit are at much higher risk for death than obese persons who are active and fit.
MRI's seem to be the only real way to tell if you're TOFI right now, so in order to keep your internal fat deposits at bay then a combination of diet and exercise is the way to go. If you just want to look thin, then maybe all you need to do is diet, but if you want to actually be healthy, then exercise has to be added as well.