I highly recommend this New York Times article by Gary Taubes entitled "Is Sugar Toxic?"
One always hears the dogma that fat is the bad thing in one's diet. This article is a highly readable summary of the argument that in fact it is sugar, not dietary fat that is bad, and not just for causing diabetes and obesity, but cancer too. For example, he discusses the point that cancers used to be rare in the Inuit (who ate lots of fat, but little sugar) but have risen since their sugar intake rose.
I predict that eventually, this issue will be finally settled, and the dogma about fat being the evil will be put to rest. It will be interesting at that time to see how many lawsuits are filed against all the health agencies and corporations that have for decades railed against fat in the diet, while ignoring sugar, and against the industries that promote sugary diets.