There's a great article in the New York Times about the (probable) dangers of sugar, written by Gary Taubes :
Gary Taubes is a respected science journalist and author of a book I read last year called (in the UK) The Diet Delusion ("Good Calories, Bad Calories" in the US).
The Diet Delusion is a detailed investigation of the the problem of obesity, diabetes and related problems, and posits that the causes of the modern epidemic in the west is primarily diet. Carbohydrates and sugars. This book has had a major impact on me and what I eat.
Taubes has followed up The Diet Delusion with a shorter and easier to read book called Why We Get Fat. I can highly recommend both. But the NYT article is a condensed version of some of the argument and a must read.