And while obesity rates have leveled off in America overall there are some demographic groups that are still seeing rising rates of obesity, metabolic syndrome and other problems. And while the rate of increase of obesity has slowed or stopped, at least for a while, obesity rates themselves are far too high. Most estimates tag 66% of the American people as "overweight or obese" and roughly 30% as frankly obese. During the time that obesity rates have risen in the US, predictably, so have rates of type II diabetes, hypertension and metabolic syndrome. So have rates of disability and so, of course has the cost of providing healthcare and accommodation for the obese.
Its not necessarily a huge mystery why Americans are so fat... or is it? Often in science what seems obvious isn't true and there are a number of fairly radical scientific theories about modern obesity that range from infectious causes to obesogen endocrine disruptors to fructose. In the end, I think a common denominator is this: there is something "wrong" with much "modern" highly processed (pure nutrient) food.