I think the sedentary part is far more important. I grew up in the 1970s in the US, and if anything, we ate worse than we do now with our current concern with c

I think the sedentary part is far more important. I grew up in the 1970s in the US, and if anything, we ate worse than we do now with our current concern with calories and nutrition -- we had fast food a couple of times a week, drank soda daily, and ate those awful sugary cereals like Lucky Charms. And yet we didn't (on average) get fat the way kids do today. We burned off those excess calories running around outside and riding bikes.