I wonder though if with the advent of GLP1 drugs, if obesity may already be a solved problem, but merely a matter of time?
I imagine, as with anything, perfect doesn't need to be the enemy of good enough. A huge multifaceted issue like obesity could be addressed from many angles.
Japan has an obesity rate of 4%. By law they require every school to employ a professional nutritionist, which requires 3 years of additional training on top of their education degrees. In a particular example of 1000 kids, not a single child is overweight. Every nutritionist is required to design the school's food curriculum such that all meals are made from fresh foods and to be balanced according to all the food groups, and they forbid even the use of processed pastes. All meals are made from fresh foods on-site.
Then the kids are then taught how to eat well and to fully cover their nutritional needs from 6-18. This would be the non-ozempic way to influence a nation to eat well.
https://peterattiamd.com/outlive/
As for the food supply, I have no doubt that many people are impacted by subclinical micronutrient deficiencies, whether it's sulphur or zinc or D3 or something else. But the evidence indicates that's less important than excess macronutrients for most people.