Popcorn legend has it that when Quadequina, an Indian brave, brought a deerskin bag full of popped corn to the first American Thanksgiving in 1621, the Pilgrims at Plymouth didn't know what to do with the funny looking kernels. Settlers later served them doused with sugar and cream. "It's still an excellent breakfast," says Joel Herskowitz, 40, an assistant professor at Boston University medical school. "But I'd suggest having them with raisins and low-fat milk instead."

Herskowitz contends that the Pilgrims may have unwittingly stumbled across the ultimate cure for corpulence. In The Popcorn Plus Diet (Pharos Books, $14.95) he proposes a comprehensive weight-loss program, using popcorn primarily to satisfy the munchies. A 21-day-diet meal plan relies on low-calorie standards like baked fish and fresh vegetables. But it also includes such novelty recipes as green peppers stuffed with ground popcorn, a potato-and-popcorn casserole and his own favorite—pop-'n'-bake chicken (see box). Says Herskowitz, "The aroma from baked chicken coated with crushed popcorn is fantastic."

Though it is a far cry from nouvelle cuisine, Herskowitz's diet, drawn up by a registered dietician at Boston's Joslin Diabetes Center, is nutritionally balanced. Served without salt or butter, a cup of fluffy popcorn is both filling and high in fiber content but has only about 30 calories. Addicts can snack on plain popcorn, he says, and still lose weight. "There's no way to eat popcorn fast," he adds. "The key thing is the crunch. You have the satisfaction of chewing."

Herskowitz himself is living proof of the diet's effectiveness. Now fit and trim at 5'10" and 150 lbs., he fought a lifetime-battle with his weight, at one point ballooning to 200 lbs. "Food for me was like Mount Everest for Sir Edmund Hillary," says Herskowitz. "I ate it because it was there." But three years ago, he impulsively bought a hot-air corn popper on sale. "I discovered I was able to control how much I ate, knowing that later I'd treat myself to a nice, warm, fragrant bowl of popcorn," he says.

Between teaching pediatric neurology at Boston University and maintaining a private practice for children, Herskowitz offers counseling and group classes in weight loss at Boston City Hospital. To stay slim himself, he keeps one air popper at his hospital office and another at his eight-room Victorian home in suburban Framingham. He has even made up a batch of bumper stickers saying, "Have You Hugged Your Air Popper Lately?" He also touts microwave popcorn, though he warns against buying brands that are loaded with butter and other additives.

Herskowitz's personal passion for popcorn is so great that he sometimes dreams about a dump truck arriving at his home and unloading a mountain of it on his front lawn. But he has not lost any sleep worrying about skeptics who might pooh-pooh his diet plan. After all, this is one diet that everyone agrees is full of hot air.