Comment by baubino

> weight is largely a function of calories in versus calories out

Yes, but calories are much easier to rack up in some foods compared to others. There’s this great exhibit I took my kid to see in a science museum that showed that the number of calories in four twinkies was equivalent to something like 20 pounds of carrots. Not sure if those were the exact numbers (it was a long time ago) but the point is that in the modern world it is virtually impossible to become obese if you are eating even large amounts of, say, baked chicken and steamed veggies. No obese person is overeating healthy foods.