You might think that officials in New York City, which has more people than all but 11 states, had enough to do providing basic city services. But Mayor Michael Bloomberg believes that what New Yorkers really need is a better diet, and he's just the man to order it. A politician's work is never done. At the mayor's urging this week, New York's Board of Health voted to ban restaurant use of artificial trans fats, those liquid oils made solid through hydrogenation and found in all manner of fried, baked and processed foods. Many of these products aren't particularly healthy,...