Reading Gutty's post I was reminded of a question I have, so this goes out to all those with some background in fitness training/medicine.
We all know that being extremely underweight or overweight is a major health problem. On top of that though, being moderately overweight can lead to heart problems, blood pressure etc.
So what about people who are moderately underweight? The "skinny" guys don't fit into the ideal weight range either, so what health risks do they face due to their mass, or lack of.
Oh, something else. I get to spend a fair amount of time at two businesses, a bike shop and a toy shop. One thing I have noticed in my time there with the kids I see (I'm talking say 7-18) is that the kids who are regular customers in the toy shop (Warhammer stuff is the big seller) are much more likely to be overweight than the regular customers I get buying bike stuff. The majority of all customers are pretty average but quite a number of the hobby enthusiasts are what you would call overweight. I could count the number young, overweight regular customers I see on one hand.
This is by no means a real study, just something I've noticed.