I really identify with what Nat said. For me, when I was a kid I ates tons of sugar daily and was active and did not have a weight problem. This may have been the beginning of the problems that would lead to my current health struggle. As I got older I started to fight the weight and starve myself. The short version is that eventually, my husband realized that something was wrong after we were married. I had ended up with insulin resistance and PCOS. Once I became insulin resistant, the weight had piled on and no amount of dieting with carbs was going to help me. I am lucky to have a name or label for what happened to me. But it is my responsibility to take control of the insulin resistance / PCOS and the dietary changes that I have to make. The down side of this struggle is that my body demands sugar, and I have to fight it every day. I'm guessing that an inordinate amount of people on this sight also have insulin reistance and, according to studies, 20% of the female population alone has PCOS which goes hand in hand with insulin resistance (hence obesity). Certain trends towards medical problems run among cultural and regional populations, and this may be part of the explanation you are looking for.