I can’t recommend reading A Chemical Hunger enough. These scientists are right, obesity isn’t a willpower issue, despite common belief to the contrary.
TL;DR: We don’t know why obesity is. Yeah sure you eat to much, you get fatter. But why do some people crave so much excess food? Why does their metabolism try so hard to keep the fat in? Why is the obesity epidemic worsening everywhere in the world, despite measurably improved eating habits over the last ~15 years?
The article goes at length to disprove mainstream myths like “not enough exercise”, “too much shit in our food”, etc. Truth is, we don’t know what’s happening chemically (same issue as the scientists encounter in the NYT article). However, the thesis of A Chemical Hunger is that there are good reasons to think that everyone has a “lipostat” which dictates how much fat we should have. Too skinny, and you will want to eat more and gain weight faster, and vice-versa. Yet for an increasing number of people, the lipostat is breaking.
The open question is, why? Right now, we don’t really know, but we really aren’t studying the biochemical causes of obesity hard enough due to this stupid belief that fat people are fat because they’re “weak minded” or whatever.