We won't know what we don't know for a long time
In total agreement, and would put a finer point on this. Causation is impossible to be certain about. The variables you mentioned, plus many others, are themselves packed with variables. We simply don't have the computing power yet to even get close to identifying interrelated causation.
However, it's pretty clear people are still looking for the sound bite/silver bullet that will absolve them of any personal responsibility for their health. Eat less, eat better, exercise (actual exercise), find ways to re-center and relax regularly. It's a simple approach we all already know works but just won't do.
Until we change lifestyles and refuse to support putting absolute junk and dangerous substances into our body (like, *never* to do fast food!), nothing will change. Given our histories, nothing will change for the majority of people.
