In September, McDonald's announced plans to cook its fries in healthier oil. And not a moment too soon. Just a few days later the Centers for Disease Control and Prevention announced that in 2000 (the latest year for which final figures are available) the death rate in America, adjusted for the fact that the population is aging, reached an all-time low. Not only that, but life expectancy reached an all-time high, of about seventy-seven years. Obviously, those numbers can mean only one thing: America is in the grip of a gigantic public-health crisis. To wit—an obesity epidemic!

That America is marching fatward seems not to be in doubt. Obesity has risen substantially in recent years, to 31 percent of adults, according to the most recent data from the National Center for Health Statistics. Soft-drink cups are bigger, restaurant portions are larger, and health campaigns condemning fatty foods have persuaded people, wrongly, that they can eat twice as much bread as before, provided that they cut down on the butter. Also not in doubt is that other things being equal, being blubbery is not good. Still, one cannot help scratching one's head. If Americans are living longer, and if they are dying less (so to speak), and if, as the CDC reports, the proportion rating their own health as excellent or very good has remained at a solid 69 percent for the past five years, what exactly is the problem?

Call me oversensitive, but I think I detect a hint of snobbery in the national anti-fat drive. More than occasionally I read things like a recent article from the online Bully Magazine, which was headlined "AMERICA: LAND OF THE FAT, DRUNKEN SLOBS." The author, one Ken Wohlrob, writes, "We're quickly becoming a society of sloths who spend their free hours driving around in SUVs and staring at televisions or computer monitors ... Goddamn, as if we need more fat, bloated people in America." Do I sniff a trace of condescension here? In the September issue of The Atlantic a letter writer named Ken Weiss pointedly (and wrongly) mentioned that "more than 50 percent of our population is obese" amid a list of ways in which America is inferior to Europe, beginning with our shorter vacations, continuing through our lack of a national health plan, and ending, inevitably, with our "polluting SUVs." It's not just that Americans are fat, apparently. It's that Americans are the kind of people who would be fat, in the kind of country that would encourage their piggishness.

What is to be done? The letters pages of magazines are often good places to preview the great bad ideas of tomorrow, and recently three letters in The New Republic offered a peek. The first, co-signed by the executive director of the Center for Science in the Public Interest and an academic nutritionist, said that the government should "slap small taxes on junk foods like soft drinks" to generate money for public-health campaigns. The next letter, from someone with the Center for the Advancement of Public Health, in Washington, D.C., said, "No one is suggesting the creation of a refrigerator police, but so long as the government is spending $360 billion per year at the federal level on health through Medicare, Medicaid, and the Children's Health Insurance Program, the government's interest in trying to prevent needless illness and death from obesity is kind of simple." The third letter came from a professor of public-interest law who wrote that he had helped to sue McDonald's for "failing to disclose the fat content of its French fries." He warned that more such suits could be on the way. "As with smoking," he wrote, "health advocates may increasingly be forced"—forced?—"to turn to the courts if legislatures continue to do little or nothing about the problem."

If obesity really is such a big crisis, I want to suggest a different approach, because the ones above seem deficient. For one thing, snack taxes that pay for public-health campaigns, and lawsuits against food companies, seem pretty likely to fatten the wallets of the people advocating them—public-health activists and lawyers—without necessarily making anyone any thinner. Besides, most people snack sensibly, so why should they pay to harangue lazy gluttons? And I know of no conclusive evidence that people are fat because food companies fail to disclose that fries and bacon cheeseburgers are fattening.

It seems to me that the only honest and effective way to confront this issue is to tax not fattening foods or fattening companies but fat people. It is they, after all, who drive up the government's health-care costs, so it is they who should pay. What I propose, then, is to tax people by the pound.

This needn't be very complicated. Fat-tax rates would be set by a National Avoirdupois Governing System (NAGS). To hit the worst offenders the hardest, the tax could be graduated. People would pay one per-pound rate above the "overweight" threshold, and a stiffer rate above the "obese" threshold. Fat people might not like this tax, but of course they could avoid it by becoming thinner.

In fact, I might go further. Carrots often work even better than sticks, so I propose a skinny subsidy to complement the fat tax. People who maintain trim, firm physiques should be rewarded for their public-spiritedness with large tax credits—funded, of course, by the fat tax.

My plan would address the nation's fat epidemic equitably and efficiently. It would make Americans put their money where their mouths are. And did I mention that I weigh 135 pounds?