What is the Scientific Evidence for the Best Diet?

[ForMyThunder]

I just finished watching the documentary "Fat Head" and I was very surprised (and confused) about the outcome. Long story short, if you haven't watched it, a guy goes on a fast food diet for a month (much like Morgan Spurlock) but he ends up losing 15 lbs. And all the while he goes through these scientific facts and papers about how saturated fat isn't actually bad for your health and other things that I found interesting. But I don't know which way is up anymore, and I was wondering what exactly is the best diet, scientifically?

 

[Perfection]

Let's see him keep it off