Such outcomes suggest almost limitless opportunities for creative pleading. Why, after all, stop at punishing the sale of fatty foods? Why not prohibit any activity that contributes to obesity?

New York State Assemblyman Felix Ortiz (D) already has this bright idea. A few years ago the Brooklyn legislator proposed six separate bills that would have slapped high taxes on the sale of fatty foods, movie tickets, video games, DVD rentals and other items ostensibly promoting sedentary living. The projected extra $50 million a year in revenue, he argued, could be earmarked for public exercise and nutrition programs.

In the face of such zealotry, thankfully, are signs of resistance. Nearly a year ago the House of Representatives passed the Personal Responsibility in Food Consumption Act (H.R. 554). This measure would shield food distributors and restaurants from civil liability for obesity-related claims. The Senate, with typical glacially-paced deliberation, has yet to act on its own companion measure (S. 908). More promisingly, roughly two dozen states to date have banned obesity lawsuits against restaurants.

Few would dispute obesity is a real and growing problem. The Centers for Disease Control has estimated that 44 million Americans were clinically obese in 2001, a 74 percent increase over the figure for 1991. And the U.S. Surgeon General estimated early this decade that nearly 10 percent of the nation's health care expenditures -- $117 billion annually -- are attributable to obesity and/or physical inactivity. The public tab for treating diabetes, heart disease, stroke, kidney failure and other obesity-related complications is enormous, especially for patients without insurance.

But instead of getting people to slim down by discovering villains, there's a better avenue for action. It's called the market.

People, by nature, tend to want to live as long as they can. And they have a tendency to seek information enabling them to do this. In recent decades, there has been a welcome explosion of preventive health care information available through magazines, the Internet, diet books, exercise courses and employer-sponsored wellness programs. Smart consumers tend to read up on these things.

Restaurants know it's a different world, too. That's why family-style chains such as Applebee's and T.G.I. Friday's have devoted parts of their menus to accommodating the calorie-conscious. Fast-food chains such as Subway and Baja Fresh openly tout themselves as healthy low-fat alternatives to their competitors. Even big, bad McDonald's has adjusted to the new realities, phasing out its supersized portions and introducing items such as salads and yogurt parfaits.

The campaign to punish purveyors of "toxic" foods, however, works against such tendencies. John Banzhaf, Felix Ortiz, Kelly Brownell and like-minded activists might deny it, but they harbor a deep mistrust of most people's ability to exercise sound judgment. The "social responsibility" they would impose upon restaurants and other food retailers is a pricey ticket to individual irresponsibility.