A few months ago I went to dinner at a steakhouse in New York specializing in huge hunks of aged beef that violate every precept of healthy eating. Let’s not even discuss the fries or the desserts. Because the restaurant is part of a chain, it is required, under one of Bloomberg’s other mandates, to indicate the calorie count for each dish on the menu.

It was a revelation. A hamburger turns out to have 1,800 calories! I’ve been off beef pretty much ever since.

So nannying does work. It has worked as well in the case of banning cigarette smoking in public spaces. I was initially opposed to this, on libertarian grounds. The secondhand smoke argument seemed far-fetched in an outdoor open space like a public plaza, and the intention seemed clearly just to stigmatize smoking in general, in order to get people to quit (or not to start) for their own sake.

But the results have been so dramatic that my libertarian instincts have been overwhelmed. During the 1990s, about 70 percent of high school students said they had tried smoking a cigarette. By 2009 the percentage was down to less than half. Regular users peaked at 36 percent in 1997 and were below 20 percent by 2009. Frequent users went from 12 percent in 1991 to 7 percent in 2009. Thousands of lives have been saved.