We (Americans) didn't understand CICO any better in the past. I'm not saying you're wrong, but the way we get our food has changed dramatically. For the most part, we know what we're supposed to eat. It's just so much easier to eat poorly now. We need to change incentives to make it more costly to eat unhealthy food.
Absolutely! There are a ton of cheap and easy ways to get calories these days. In the past we didn't need to worry so much about people understanding CICO.
However, now we have two options:
1. Education
2. Banning a ton of food-types.
Both seem hard at scale, but #1 can be achieved on an individual level, at least.
