This short NY Times documentary was really good and clear about the link between the links between the shaky science, the policy decisions, and the current levels of obesity in the US:
It doesn’t describe a conspiracy, though, just politicians who feel they must make health recommendations even when they know that the research is incomplete. And it’s a whole open question about whether that’s really wrong: after all, we would have loved politicians to start making decisions to avert climate change twenty years ago, even when the science wasn’t settled yet.