Plus it is very low fat and low carb.
"The study looked at chocolate's (Total Antioxidant Capacity) TAC and the amount of procyanidins it contained. Milk chocolates have the lowest TAC and procyanidin levels, and baking chocolates contain low levels of procyanidins. The alkalinizing process used to reduce the acidity of chocolates substantially lowers the quantity of procyanidins. Cocoa powder, being the least processed chocolate, contains the highest levels of TAC and procyanidins."
http://www.newstarget.com/006754.html