Calvin Trillin's exploits as an eater are legendary. Acting as his own Boswell, he reports on off-beat meals and restaurants in the New Yorker, The Nation and other publications.

One day there will be a college thesis written on his work. It should be - a piece of cake. Based on his books, "America Fried" and the current "Alice, Let's Eat" (Random House $7.95), Trillin is the Inspector Clouseau of restaurant and food writers.

Modest of stature and girth, Trillin never strikes fear in the heart of a waiter with a snap of his fingers. Furthermore he's a bumbler who doesn't dress for dinner or know how to slip $5 to the maitre d'.Le Circle de Gourmets and "La Toute" of Kansas City - his home town - frown.

His techniques is all wrong too. When he stumbles upon a world class chili parlor in a strange town, surely it is only an accident. Trillin's taste for externals - decor and that mystic element, ambiance - is lacking. He cares only for internals, for what is in or about to go into his mouth.

Though he passed through Yale University and Time Magazine, he is, he insists, merely a representative of "My Fellow Traveling People," salesmen and others whose work forces them to eat out often, far from home. These wanderers are at the mercy of a fickle food god, who loves to tempt the hungry with neon signs promising manna but delivering only empty calories.

Trillin's writings are a supremely didactic attempt tt to right the balance. They are also very funny. "Twaddle," twits a dour nutritionist as Trillin recommends fried Italian sausages as an antidote to a health food salad.

"Warped!" explodes a chain restaurant executive as Trillin denounces the verticle integration of the broiler industry and praises a place where the menu "specified native chicken and a 30-mintue wait." Anyone with such views is bound to have enemies.

If that troubles Trillin, it didn't show during a visit here recently. A network of food fanciers across the nation offers him unsolicited tips and invitations. "It's fun," he said, explaining the purpose of his writing. "The question is not where the family goes for mom and pop's 40th wedding anniversary. It's where you go the first night home after three years in the service."

His own nostaglic reminiscences brought national attention to Arthur Bryant's, a down-at-the-heels barbecue restaurant in a rundown section of Kansas City. "The Chamber of Commerce hates all the attention that Arthur has gotten," Trillin said. "They don't want visitors to see the neighborhood. Of course they all eat there for lunch. They're not crazy."

A restaurant in the depths of Missouri ("under the Esso symbol on the map") serves pan-fried chicken and five fresh vegetables for lunch. It survives, Trillin feels, only because the town is too small to support a fast food franchise.

"I look on these places as the Indians look on the buffalo," he said. "As long as they're around I'm okay. In some ways things have improved for Traveling People. Simple restaurants with limited menus, often country French, are appearing outside New York. Menus are more eclectic. But the franchises have driven a lot of people out of business."

There is no shortage of material, however. His new book takes the reader to Kentucky for chicken, Vermont for wild game, Nebraska for steak, England for French food, San Francisco for crab and a flight from New York to Miami for a memorable airborne picnic.

His family plays a role in many of these adventures. Alice, who inspired the title "Alice, Let's Eat," was unlikely choice for a wife, he confessed. She didn't drink or stay up late and was no barbecue enthusiast; qualities the very opposite of those the young Trillin desired in a spouse. They married nonetheless and are wedded still, he speculated, because her addiction to desserts allows her to endure the oddities that come before it.

At 5, his daughter Sarah carried a bagel as a security blanket whenever the family went to a Chinese restaurant. Two years later, she doesnt't do that anymore, she wants the world to know.

It is necessary, however, to take whatever Trillin writes about the Yahoo eating habits of his two daughters with several grains of salt. They are their father's children, so obviously he is playing the protective parent, hiding their true eating talents for fear a flock of boys with Calvin Trillin-like appetites will want to court them.