High-protein diets, America's latest food fad, are like an overstuffed deli sandwich -- some healthy nuggets here and there surrounded by a fair amount of unhealthful baloney.
That, at least, is the view of mainstream nutritionists, many of whom feel that Americans hooked on books like "The Zone," by Barry Sears, "Protein Power," by Drs. Michael and Mary Dan Eades, and "Dr. Atkins' New Diet Revolution" are being fed a mixture of truths, half-truths and totally unproven assertions.
For years, nutritionists have urged us to eat less fat and more complex carbohydrates so that we'll have fewer heart attacks and be generally more slim, healthy and vigorous.
That's still a basically sound message. But somewhere along the line, it's been twisted by some into a license to eat unlimited amounts of pasta and potatoes, with obvious results at the waistline.
But there's a less obvious result of this love affair with carbo, too, a feeling on the part of many that "carbohydrates have failed them," says Larry Lindner, executive editor of the monthly Tufts University Health & Nutrition Letter. For that reason, he says, many people are hungry for any self-appointed guru who seems to have a better message.
The trouble is, switching from a carbo-heavy diet to one loaded with protein is not necessarily better. In fact, some parts of the high-protein message are not only unsupported by any scientific evidence but may even be dangerous.
To sort out what's valid and what's not, we consulted leading nutritionists, as well as the Harvard Health Letter of January 1997 and the Tufts nutrition letter of May 1996. Their consensus is that at least some high-protein diets are based on a number of myths. Such as:
Myth No. 1. Americans do not eat enough protein.
This is unlikely, except for frail, elderly people, poor people who do not get enough calories every day, and perhaps some elite athletes who put huge demands on their bodies.
Sears acknowledges that most Americans "probably consume adequate protein in the course of a day, but not at every meal." But in the next breath he contends that because people have been told to shun fat, which often comes in the same foods as protein, many people on diets are protein-deficient.
A Swampscott, Mass., biochemist, Sears runs a biotech company called Eicotech Inc. He is not a nutritionist and complains that real nutritionists "have no command of the literature." He recommends reducing carbohydrates to 40 percent of calories, boosting protein to 30 percent and keeping fat at the level of 30 percent or less nutritionists suggest.
Men, he says, need 100 grams of protein a day, and women, 75, on average. To get that, you'd have to eat 14 ounces of steak or a 10-ounce steak plus three servings of milk, yogurt or cheese every day if you're a man and 10 ounces of steak or a 6-ounce steak plus three dairy servings if you're a woman.
By contrast, the U.S. Department of Agriculture and the American Dietetic Association recommend diets that provide 15 per- cent of calories from protein, 55-60 percent from carbohydrate and up to 30 percent from fat.
This translates to about 75 grams a day of protein for men and 65 for women, says Dr. George Blackburn, medical director of the center for the study of nutrition and medicine at the Beth Israel Deaconess Medical Center. To get this, you'd need to eat 6 ounces of steak or the equivalent for a man, or 4 ounces of steak or the equivalent for a woman. And unlike Sears, Blackburn and other nutritionists advocate getting lots of protein from grains and vegetables like beans and lentils.
The bottom line is if you eat enough calories -- 2,000 a day for women, 2,500 for men -- you're almost certainly getting plenty of protein. Many foods contain a mix of fat, carbohydrate and protein.
Myth No. 2. Eating too many carbohydrates leads to hyperinsulinemia -- chronically high levels of insulin.
This is one of those half-truths. The idea, say high-protein gurus, is that eating tons of carbos makes the body pump out too much insulin, the hormone that helps transport glucose from carbohydrate breakdown into cells for energy.
Because insulin does increase triglycerides (the fat molecules that wind up as plaque on artery walls) and lowers HDL, or "good cholesterol," the high-protein gurus contend that too much insulin is the cause of health troubles.
This notion contains "just enough of a kernel of truth to mislead," says Dr. Dean Ornish, president of the Medical Research Institute in Sausalito, Calif. He says none of the high-protein gurus has "published a single study in any peer-reviewed journal about anything, much less the benefits of their recommendations."
But insulin does not, as protein gurus say, promote storage of glucose as fat, provided you burn more calories than you eat.