Stomachs on legs are proud to present

The Democratic contenders include Gov. Bill Richardson, a veteran of the Atkins and liquid diets who wears a double chin despite daily workouts. Senator Barack Obama, who was chubby as a child, refers to himself as skinny in speeches and barely touches fatty foods — except at events like the Iowa State Fair, where he ate caramel corn, pork and a corn dog for the cameras. At one campaign event, Senator Hillary Rodham Clinton said she prayed to God to help her lose weight.

On the Republican side, there is Mike Huckabee, a self-described “recovering food addict” who lost 110 pounds a few years ago. Rudolph W. Giuliani and Fred D. Thompson are on diets imposed by their wives. Mitt Romney is so vigilant about nutrition that he eats the same thing every day: his wife’s granola for breakfast, a chicken or turkey sandwich for lunch, and pasta, fish or chicken for dinner.

And John McCain probably spoke for all the candidates when he arrived at a New Hampshire college for a speech on Sunday night and surveyed the snack foods set out backstage. “I’d love some spaghetti,” he said wistfully, as if a warm, comforting meal could somehow be conjured out of the air.

Those wanting to be president must never, ever refuse or fumble the local specialties, lest they repeat the sins of John Kerry (dismissed as effete when he ordered a Philly cheese steak with Swiss in 2004) or Gerald R. Ford (on a 1976 swing through Texas, he bit into a tamale with the corn husk still on).

So this fall, Mr. Giuliani has visited what seems like every diner in New Hampshire. Mr. Romney, whose idea of a late-night fridge raid is a bowl of cereal, has been ordering milkshakes. Mrs. Clinton introduced calorie and fat counts on White House menus when she was first lady, but a few weeks ago in Tama, Iowa, she had a loose meat sandwich — a kind of Sloppy Joe, but without sauce — and fries.

But while the tradition of campaign consumption endures, physical standards have changed drastically, the portly presidents that Americans elected in the late 19th century giving way to thinner, fitter leaders.

Mr. Huckabee also eats lightly, sticking largely to salads, protein bars and steamed vegetables. But if a campaign trip he took this month is any guide, his mind tends to wander into more dangerous nutritional territory. At a metal factory in Cedar Falls, Iowa, he stared as a worker punched out a flat disc. “Put a little pepperoni and cheese on that, and you’re made,” he observed. One machine, he said, looked like a grill for rib-eye steaks.

Mr. Huckabee, once so overweight as governor of Arkansas that a chair collapsed under him at a meeting, said in an interview that obesity could put politicians at a disadvantage.