There are a few things that are going on here which could be supporting raising obesity rates:

-The Farm Bill and USA Sugar Program, which is a bipartisan issue but which shouldn't exist in the first place https://en.wikipedia.org/wiki/U.S._Sugar_Program

-Increasing use of social media and sedentary lifestyles. When you are just inside on your phone all the time this is NOT healthy.

-This obesity problem is probably going to kill more people than COVID and the opioid epidemic, but noone wants to talk about it as it directly threatens various established interests.