But good health is a lottery. Vegetarians are not immune to disease; people who don’t smoke, like people who do, succumb to cancer and heart attacks; strokes befall both the lazy and the fit; and if you get sick, it doesn’t necessarily follow that one less hamburger or one more hit of beet-and-wheat grass juice would have spared you. Many winners of hot dog-eating contests live into their dotages. To be alive is to be at risk.

Americans who conscientiously seek to obey the continually shifting dietary dictates of the fear brigade need to ask themselves: Where does prudence end and joy-sapping paranoia begin?

In the 1970s, Americans were told to eat margarine instead of butter. Eventually, it turned out that these solidified vegetable fats were worse for the heart than butter — something my mother, steeped in Illinois farm wisdom, intuited from the first. People were also told to shun eggs because of demon cholesterol. Then, in February, the national Dietary Guidelines Advisory Community quietly reversed 40 years of yolk phobia, admitting that cholesterol wasn’t a “nutrient of concern” after all.