And just plain too much food. We live in abundance --- but we don't have to eat 3 hamburgers --- 1 can be enough. And if we live sedentary lifestyles, we should adjust for that. The contruction workers here might eat more than the welfare types who just lay around --- but they don't have the same weight problems.
You know when I was young and prone to laying around I would GAIN weight when I got back on a jobsite! It was mainly muscle. The two times I decided I needed a lengthly break I gained weight when I came back!! Thise were the days!!!