Freakonomics - a book and blog I read frequently - is intended to question the "conventional wisdom" in entertaining and interesting ways. Unfortunately, it's also highly selective in the use of data sets so that it always comes to the "opposite" or "opposing" view. That's what sells books.

Obesity is a direct, causative (not correlated) factor in heart disease as well as diabetes. There is ample clinical research to this conclusion.

Yes, we often hear about the healthy athlete running along and dropping dead from a previously undiagnosed heart condition. That't not heart disease, that's a heart defect. Very different.

You don't need a lot of research or tables of data to know the effects of being overweight on most (not all, most) people who get called in for a cardiac. They are fat. In fact, I can't think of a single cardiac arrest victim I've ever hauled out of the woods who WASN'T overweight. I only run the calls where there's a rescue/extrication/assist the squad component, so my experience is with people in slightly strenuous situations, not sitting at home and standing up to go pee and having the heart give out - but that happens too.

All I'm saying is take care of your heart. That's it.