That’s part of it but the deeper question is why are people more sedentary? Why do people eat more often?
What is it about our society that promotes eating more processed foods?
My feelings are that food for many people is a sedative for a stressful life. Sugar is a great drug to make you feel good temporarily.
Then there is very little quality education around good nutrition and cooking in the US. Most people just take what the learned from their parents and go with it. And if their parents weren’t food smart then they probably will not be either.
there is a lot more to the obesity epidemic than just “stop eating so much”