As a practicing Endocrinologist I will go out on a limb and say excess carbohydrates are the problem leading to obesity. Sugar (or sucrose) is a particular problem as it will stimulate insulin release from the pancreas. Insulin promotes storage of glucose and I am convinced, the growth of fat cells. I have seen patients lose a tremendous amount of weight (34 lbs over 7 months) and lower blood glucose and their amount…
The implication being, of course, that this isn't the whole story, and we are doing ourselves a disservice by chalking up everything to diet.
(I don't mean to say you are wrong about this fact by any means - I'm not any kind of expert, and you sound very convincing.)