I am not an expert but I have listened to fat people and debated with them. I had to correct many of my assumptions about obesity. Those of us who bodybuild think we know how to manage body composition and for young males that probably works. However, it is quite another matter dealing with the obese population and not at all easy to reverse obesity.
Many people have tried to account for the obesity epidemic in some western countries. The USA surely leads the world but apparently Australia is up there as well. I don't see widespread obesity in Australia compared to what I have seen in some American cities. With a huge population like America you find more extremes and thus observe some really fat people when you are shopping. Sweden has a different culture where physical shape and condition are more important. In addition, living up north requires more calories to maintain body heat and thus prevents obesity in those countries. Canadians are not as obese as Americans and you can see that difference comparing Vancouver to Seattle. What exactly causes so many to get so big? Well, that isn't difficult to specify. What is more interesting is who are the people who get obese? Do they have some genetic 'advantage' that is behind obesity? I think we will find that there are many factors combining to explain this phenomenon.
If you say that fat or obese people have something wrong hormonally in their bodies that makes it easier from them to get to that condition, what is it?
I have to ask a couple of questions too:
1. Why is this obesity problem only prevalent on some countries in the world, especially in the USA, but it doesn't happen in other parts of the world? Are people really that different or are the eating and lifestyle habits what is different?
2. When you look at the north american society before the 1970's or so, there were very little obesity problems. What caused the sudden change in some people? Something magically changed in their bodies hormonal system or did the eating/lifestyle habits change?