Linn's book has generated a $40 million business but now the FDA may step in

Dr. Robert Linn is an amiable, cherubic osteopath from Radnor, Pa., hardly the sort to touch off a controversy that has involved the U.S. government, stars like Valerie Harper and Ed Asner and thousands of uncelebrated Americans—a few of them now dead—who only wanted to lose weight.

It was Linn whose 1976 book, The Last Chance Diet, sold 2.5 million copies and spread the gospel of the liquid protein diet. Since then upwards of $40 million worth of liquid protein—chemically predigested cow hide and tendon, artificial flavoring and sweetener—has been sold, millions of pounds have been lost, and the Food and Drug Administration is looking into more than 30 cases of people who have died while on the diet. The FDA has decided to require label warnings against unsupervised use of the liquid and is considering a ban.

Linn, 43, weighed 235 pounds 11 years ago. "I was a snacker," he says. "What's more, I was a fatty as a kid. Fat kids who become fat adults have an even greater problem because they have a greater number of fat cells." Then heart palpitations caused him to abandon a golf game on the 17th hole and evaluate his health. Experimenting with diets, Dr. Linn lost 65 pounds in six months and began studying bariatrics, the reducing game. That led him to some Harvard Medical School research on substances called ketones. When the body consumes only predigested protein, it burns fat which produces these ketones. They supply the brain with energy, and the protein prevents damage to tissue, a danger with total fasts. Enter Dr. Linn, who admits, "I didn't invent the wheel. I just kept it rolling."

Starting with a small clinic in Philadelphia in 1973, Linn began giving his patients liquid protein in 60-calorie doses four to eight times a day, spiking it with large amounts of other fluids. Soon publisher Lyle Stuart read an article about Linn, sought him out and lost 83 pounds in 120 days. Stuart persuaded Linn to write The Last Chance Diet.

It became a best-seller. Prolinn, a nonprescription brand of the protein elixir, was developed for the doctor (he donated all rights to a nutrition foundation). Soon 100 competing concoctions launched a major business.

Linn—whose book warned dieters to consult their physicians—opened branch clinics with thick carpets, thin nurses and consulting psychologists in New York, Washington and three other areas. Rival protein reducing salons cropped up everywhere.

Celebrities like Harper, Asner, Vicki Lawrence and Richard Dreyfuss all but chugalugged the stuff. Jacqueline Onassis reportedly checked daughter Caroline into a liquid diet clinic. Many do-it-yourself-dieters, unwilling to pay the clinics' fat fees (averaging $150 for the first examination and $60 a week thereafter), bought the liquid protein on their own at $15 a quart.

The protein diet at best is no panacea. Side effects include flatulence (lecithin granules or antacids may help, Linn says, but anyway, "It's a small price to pay for loving yourself again") and bad breath. ("Tell people you're sorry about your breath but you're on a diet.") Of course, dieters who don't accept Linn's training on changing eating habits quickly regain lost weight. Lyle Stuart was one.

When the deaths of liquid protein dieters were disclosed, the FDA stepped in. Commissioner Donald Kennedy believes "the diet was at least a contributing factor or a cause."

Linn, who did graduate work in nutrition, says, "The FDA announcements have been good in that they'll stop overweight people from buying these products without proper medical supervision." Half the fatalities, he says, suffered from preexisting diseases; he has insufficient information about the rest. He nevertheless advocates strong warning labels on liquid protein and perhaps making it obtainable only with a doctor's permission.

Linn's constant travels give him less time than he would like with his family—wife Diane, Laurie, 15, Danny, 13, and Ricky, 8. "I've become one of the leading experts on bad restaurants and good airlines," he says. Life on the road has also added an incongruous dimension to his other problems. In the past year he gained 18 pounds.