Every day, in magazines and books, on TV and the radio, we are flooded with advice on what foods to eat. Some of this advice is nonsense--trendy weight-loss regimes, which can actually be harmful--and some is contradictory, as even scientists will vacillate on such subjects as animal versus nonanimal fat, saturated versus unsaturated fatty acids. There are a few good books that cover nutrition in general and even some that tackle specific health goals,...