Even now, when Janice Min sits down to a dinner of heavily marbled prime rib, tender at the center, crisply roasted at the edges, she can hardly believe it. "Once this kind of meal was strictly taboo, now it's a part of my everyday eating," says Min, who, at five feet two inches, weighs 105 pounds. For years, Min, 27, planned her meals as if she were a spokesperson for the U.S. Department of Agriculture's food pyramid, rarely deviating from its nutritional formula of maximal complex carbohydrates and minimal fat and protein. Even so, the avid New York City jogger found herself hungering for a fuel fix that wouldn't leave her light-headed, bloated and craving sweets within an hour of filling up.
So she decided to go against the grain and ditch the diet that current conventional wisdom holds is best -- roughly 55 percent of calories from carbohydrates, 30 percent from fat and 15 percent from protein -- for a formula that dictated more than double the protein. Within six weeks, Min was eight pounds slimmer "without even trying," and a few months later she ran a personal best in a five-kilometer road race. "As soon as I started eating protein at every meal, I felt myself getting leaner, stronger, it seemed, by the day."
Min isn't the only one rushing madly away from rotini to join a campaign touting more protein and fewer carbs as the ticket to good health and a perfect body. Leading the crusade is a troop of diet-book authors, including biochemist Barry Sears, Ph.D., coauthor of Enter the Zone and Mastering the Zone, and medical maverick Robert C. Atkins, M.D., author of Dr. Atkins' New Diet Revolution and Dr.Atkins' Quick and Easy New Diet Cookbook.
What sets these and similar diets apart from the highprotein diets popular in the 1970s, including one by Dr. Atkins, is the assertion that loading up on carbohydrates leads to a loading on of pounds. High-carbohydrate diets, say the critics, claiming that recent research backs them up, tip the body's hormonal balance, hindering the breakdown of stored fat and actually promoting its deposit. The ideal diet, they say, calls for approximately 40 percent carbohydrates, 30 percent fat and 30 percent protein.
Ridiculous, declares the high carb camp, arguing that protein prosely'tizers' claims are a mishmash of pseudoscience and utter nonsense. Yet the success of such books has shaken mainstream doctors and nutritionists, who ruefully remember just yesterday when carb-rich grains and greens were enjoying star status among the diet and fitness set. Adding to the carb camp's woes, the National Center for Health Statistics in Hyattsville, Maryland, reported recently that, for the first time ever, a third of Americans over age 20 are overweight and more than half of those past 50 are fat. How, the grain gurus wonder, could that have happened on our watch, the early Nineties, when the carb craze was at its peak?
For protein proponents, there's no mystery. They blame the heavily promoted USDA dietary guidelines, revised and reissued in 1990 as the "Food Guide Pyramid," which call for six to 11 servings of bread, cereal, rice and pasta daily. "It's an experiment gone awry," scoffs Michael Eades, M.D., coauthor with his wife, Mary Dan Eades, M.D., of another bestseller, Protein Power, "The pyramid is the feedlot diet. It's what they feed hogs to fatten them up. It's not appropriate for people." The problem, says Sears, is that "carbohydrates are like a drug and, like any drug, an overdose can occur." This, he contends, can happen even when you consume foods you know are healthful, like carrots or orange juice. Why? Because these, like all carbohydrates, are quickly broken down into glucose in the bloodstream, which in turn stimulates production of the protein crowd's anointed villain: insulin. The Eadeses call it a "monster hormone."
No one disputes that insulin plays a crucial role transporting glucose, the body's fuel, to each and every one of our living cells, which use it for energy. Trouble begins, the books say, when your pancreas releases too much insulin, either because you've eaten too many carbohydrates or because you are insulin-resistant, meaning your body needs more insulin than others do to get its work done. One of the hormone's primary tasks is storing excess glucose. Insulin usually stashes the surplus in the liver, but the glandular organ has a limited capacity, and when that port is full, insulin must shuttle glucose to muscle tissue or fat cells for deposit. So, the argument goes, taking in more carbs than you immediately need for energy simply invites the body to make fat, which sets off a chain of unhealthy side effects including weight gain, high blood pressure and elevated cholesterol.
Most scientists reject this scenario and its basic premise. Gerald Reaven, M.D., is especially critical. One of the nation's leading experts on insulin resistance, Dr. Reaven did groundbreaking research in the 1980s showing that the ability to metabolize carbohydrates varies widely among people, and his work is routinely cited by protein-promoting authors as backup for their insulin-as-villain theory. But Reaven, a professor emeritus at Stanford University School of Medicine, calls their interpretations flat-out wrong.
Although his studies have observed a correlation between overproduction of insulin and obesity, hypertension and high blood-fat levels, it's not clear that insulin is the cause of the trouble. In fact, he says, it's more likely that the reverse is true: Obesity, along with elevated blood pressure and blood fats, induces insulin levels to rise. "In most cases, it's being fat that makes people insulin-resistant," Reaven says. "When insulin-resistant people lose weight, they often go back to being normal."
More to the point, he adds, "the only reason you secrete more insulin is because the insulin you have isn't doing its job efficiently. There's nothing about that additional insulin that makes you gain weight." What then is the best way for insulin-resistant people to lose weight? Simple, says Reaven: Cut back on calories and exercise more.
That doesn't mean, however, that he endorses high-carbohydrate diets as the best choice for everyone. He holds the still somewhat controversial view that cutting back on carbs may make sense for the roughly 25 percent of the U.S. population who are to some degree insulin-resistant and "isocaloric" -- neither gaining nor losing weight. Some may be better off eating a diet that is 45 percent carbohydrates, instead of the recommended 55 percent, and substituting mono- and polyunsaturated fats, such as olive and canola oil, for the difference. But the reason to make the change is to ease the workload of the pancreas, he says, not to promote weight loss.
Another of Reaven's studies that the anti-pasta people like to point to involves a comparison of two groups of obese dieters in Switzerland, one of which ate more fat (which goes hand in hand with a high-protein diet), the other more carbohydrates. The higher-fat group did show lower insulin, blood sugar and triglyceride levels, but the differences were "trivial," says Reaven. More important, the two groups' weight losses were nearly the same, hardly compelling proof that a high-carbohydrate diet is a less healthful or less effective choice.
With so little evidence, why has the American public been so quick to embrace the notion of carbohydrates as harmful? In a word: frustration. Having heard that carbohydrates are good for you and "thinking all they had to do was eat less fat, many people went out and stuffed themselves with low-fat starchy carbohydrates and gained weight," says Karen Reznik Dolins, a registered dietician and past president of Sports and Cardiovascular Nutritionists, an arm of the American Dietetic Association. Few stopped to notice that a box of fat-free SnackWell cookies has about the same number of calories as a box of Oreos. The result: massive weight gain, massive disappointment and a perfect climate for the resurgence of fad dieting.
The high-protein diet books were at the right place at the right time. And like all good fad diets, they actually work, at least in the short term, which is just long enough to generate lots of enthusiastic word of mouth. Why do they work if they're based on pseudoscience? As most nutrition experts point out, they aren't only high-protein diets; they're lowcalorie ones, too. According to an analysis by Tufts University Diet & Nutrition Letter, "if you follow a 'Zone-favorable' diet to the letter, for instance, youll eat somewhere between 800 and 1,200 calories a day, which is enough to make even a petite sedentary person lose some weight."
The pounds may come off dramatically fast, but will they stay off? Critics say no. Protein metabolism produces a by-product, nitrogen, that is toxic to the body and must be flushed out with lots of water. The body gets that water by breaking down muscle tissue, which it must do anyway to get fuel in the absence of carbohydrates. So not only does a high-protein diet favor loss of muscle mass over body fat, it causes frequent urination by functioning as a diuretic. And therein lies the biggest catch: People can't or don't stay on high-protein diets permanently, because the body can detect carbohydrate reduction and long-term performance will eventually suffer, according to David Levitsky, Ph.D., professor of psychology and nutritional sciences at Cornell University. "Once you start eating a regular diet again, your body starts replacing the water, and the scale jumps right back up," says Dolins.
Beyond setting yourself up for rebound pounds, there are health concerns associated with making a protein shift. Having to break down the excess protein puts an extra burden on your liver and kidneys and, epidemiological studies suggest, may cause calcium loss (it's swept out through the urine), putting you at greater risk for osteoporosis. Moreover, a new study from the Harvard School of Public Health bolsters the view of many scientists that high-protein diets contribute to the development of cancer, particularly of the colon.
Atkins, for one, pooh-poohs the dangers of what many see as the link between high-protein diets and cancer: saturated fats. After encouraging readers to eat "chicken salad with triple the usual amount of mayonnaise," he tells them, "The evidence that you're going to get heart disease or cancer from the fat in your diet isn't strong; it's weak. It isn't persuasive; it's remarkably unpersuasive." Counters Ronald M. Krauss, M.D., chairman of the American Heart Association's Committee on Nutrition: "As far as heart disease is concerned, the connection between fat and cholesterol is unarguable and the connection between cholesterol and heart disease is unarguable except to a few die-hard skeptics who have their own agendas."
By contrast, study after study from top research labs confirm that the best way to lose weight and keep it off is to exercise regularly and to eat a lowcalorie, low-fat diet packed with complex carbohydrates like fruits, vegetables and whole grains. It's not just the USDA that says so. It's the National Cancer Institute, the National Academy of Sciences and dozens of other health-promoting agencies, like the American Heart Association.
It's not surprising why so many are united in this view. Fruits and vegetables supply a whole range of nutrients that high-protein dieters miss out on, including phytochemicals like bioflavonoids, beta-carotene and isoflavones. "There's just more and more evidence -from animal and epidemiological studies and from clinical trials- that these substances, which are rich in a plantbased diet, not only help to prevent heart disease and cancer, but even help to slow the aging process," says Dean Ornish, M.D., founder of the Preventive Medicine Research Institute in Sausalito, California, and a longtime champion of low-fat, higheomplex-carb cuisine.
Another thing that complex carbohydrates offer in substantial quantities is fiber, which health experts say we should be eating to the tune of 25 to 35 grams each day, instead of the 12 grams we currently average. In fact, says Dr. Ornish, fiber is the best antidote should insulin promote obesity even in the slightest way. "Fiber slows the absorption of the sugars that are contained in complex carbohydrates, so you don't get a rapid spike in blood sugar, you get a nice slow steady rise that gives you a constant source of energy and doesn't provoke a surge of insulin," he says. "And you don't get the fat and cholesterol that are high in protein foods. You get the best of both worlds."
What's more, if you're on a low-fat diet, eating lots of carbohydrates stabilizes your metabolism and may even boost it so that you burn calories more quickly. Normally, when your body detects too little fat coming in, its reaction is to lower the metabolic rate to conserve energy. "But if carbohydrates increase, it seems as if the body can't detect a reduction in the amount of fat coming in, so the metabolism doesn't change," observes Levitsky. Consuming carbs may even improve your mood and your relationships. A 1992 study of 233 families in Portland, Oregon, directed by Gerdi Weidner, Ph.D., found that those who switched to a diet low in fat and high in complex carbohydrates experienced a reduction in depression and aggressive hostility -- as well as in their cholesterol levels.
Finally, gram for gram, carbohydrates contain half the calories of fat. In our society, where total calorie intake today is about 9 percent higher than in the 1970s, finding any way to reduce calorie intake can only help. The key is not to treat all carbohydrates alike. Eat complex carbohydrates, not prepackaged cookies, cakes and pretzels, which, whether nofat or low-fat, are loaded with calories that add up quickly when eaten in excess. "The only way you're ever going to lose weight is if you're taking in fewer calories than your body needs," says Dolins. "There is no situation where that is not true."
NUNA ALBERTS is a freelance writer specializing in health issues.
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