there are lots of simple, well-known explanations, and they are all wrong. that was one of them. 'it's sugar' and 'it's hfcs' are two others that have popped up in this thread
by contrast, sugary foods commonly have about the same caloric density as healthy foods
so i think caloric density is clearly an important factor (you won't get fat by pigging out on lettuce and tomatoes unless you add salad dressing) but the comment i was rebutting gave the following simple, clear, and wrong explanation of the obesity pandemic
> I think the primary cause of the obesity epidemic is the widespread availability of cheap calorie dense food and a few hundred million years of evolution devoted to making biological machines designed to consume as much calorie dense food as they could find
and that just isn't an accurate description of the situation
Nuance is important.