There’s a swing in opinion happening. The current view of obesity is that it’s an effect of overeating. Obese people are largely considered to be at fault for their condition — if they’d only choose health over the pleasure of eating and sitting around, they’d cure themselves.
I used to think the same thing, but my thoughts are slowly shifting too. The first step for me was thinking that junk food might be addictive, and that it’s a superstimulus, manipulating an evolved preference for sugar and fat. I started to see it more like drug addiction (though I’m aware that lots of people disagree and think that getting off drugs or alcohol is just a choice). Later I read books like “Why we get fat” which even argue that the cause of obesity and overweight is not simply overeating.
Peter Attia talks frankly about his own shift of opinion, why he thinks the old view of obesity is wrong, and gives a few speculations on where he’s going to look for the actual cause.