Whether one prefers a Chicago dog -- slathered with mustard, relish, chopped onions, sliced tomatoes and celery salt, or a Kansas City dog -- heaped with sauerkraut and melted Swiss cheese, the hot dog is a favorite all-American food.

Also known as frankfurters, weiners, Coney Island hots, red hots, dachshunds and Vienna sausages, the hot dog is an integral part of America's food culture. "In Chicago, with more than 2,000 hot dog stands, and New York, with over 3,000 hot dog carts, you have a food that is too strongly entrenched in the local color to disappear," said Bruce Kraig, a history professor at Roosevelt University in Chicago, who is writing a book on hot dogs. There are an estimated 1,500 vendors in the District; most offer hot dogs.

Americans eat 50 million hot dogs a day, an average of 80 hot dogs per person per year, according to the National Hot Dog and Sausage Council, a trade association in Westchester, Ill. An estimated 5 billion hot dogs are consumed during the "peak" period -- the 13 weeks extending from Memorial Day through Labor Day.

Considered a "must" at most barbecues, hot dogs are also a vital part of the baseball experience. "People swear hot dogs taste better at the ball park," said Jay Boyle, general manager of ARA/Martins, the concessionaire at Memorial Stadium in Baltimore. Boyle's company offers Oriole fans four different types of hot dogs and sells over 16,000 franks during Sunday games.

The ingredients that make a hot dog taste so good -- fat and salt -- make most nutritionists shudder. A typical 1.5 ounce hot dog has 13 grams of fat, 500 milligrams of sodium and 145 calories. About 80 percent of the calories are derived from fat and over one third of that fat is saturated, according to the Center for Science in the Public Interest (CSPI), a Washington-based health advocacy group.

Manufacturers' attempts to choose leaner meats or use poultry products don't help much. Turkey or chicken dogs are still high in fat and salt, according to CSPI's associate nutritionist Jayne Hurley.

What should hot dog lovers do? Sample one made with tofu, said Hurley. One tofu dog has 5 grams of fat and 115 calories. But the salt content is still high -- about 320 mg.

San Francisco Giants fans can eat a tofu dog during a game. "Some people think it's disgusting, but it is not made for those people," said Gregory Kramer, general manager for the Harry M. Stevens Co., the concessionnaire at Candlestick Park. "We offer it for vegetarians and people on restricted medical diets."

Traditional hot dogs will never be nutritious. Nor are they a good source of protein. One hot dog has only 5 grams of protein, the same amount found in a hot dog bun. It is doubtful, however, that Americans will stop loving or eating hot dogs -- despite their reputation.