Forget the stuffing. And don't even think about cranberry sauce, candied yams, mashed potatoes, biscuits and pumpkin pie.

For the thousands of people sticking to high-protein diets, Thanksgiving dinner could be reduced to just one thing: turkey.

But that hasn't stopped Americans from following these popular high-protein regimes that urge adherents to gobble up meat, cheese, nuts and other sources of protein while slashing such carbohydrates as breads, grains, fruits and vegetables.

High-protein diets are "really, really hot," says Katherine Tallmadge, a District dietitian.

How hot? "Dr. Atkins' New Diet Revolution," the leader of the pack, has been on the New York Times paperback bestseller list for more than three years. Other titles, such as "Protein Power," "Sugar Busters!" and "The Zone," have topped the charts for weeks as well. Restaurants are catering to protein-seeking patrons; even Burger King reports that "having it your way" sometimes means a Whopper without the bun. And aside from Web sites, chat rooms and dinner party discussions, high-protein is the talk at local fitness clubs. "It's probably what you would call very trendy right now," says Rich Salke, owner of Rich Bodies Gym in Georgetown.

So how did it get to this point? After all, for the past decade, every mainstream health authority has been counseling people to eat more carbohydrates and less protein -- just the opposite of the high-protein or low-carb diets. Given this disparity, what does the scientific community think of these protein-padded regimes? And most important: Since nearly any diet that restricts consumption of some food will result in weight loss, do the protein plans keep the pounds off?

The Low-Fat Backlash

When it comes to social trends, the pendulum swings back and forth and old ideas are recycled with new names. Dieting is no exception.

High-protein diets, which have gone in and out of fashion throughout the century, were most recently "in" in the late 1960s (e.g., the Stillman diet) and early 1970s, when physician Robert Atkins's first "diet revolution" book appeared.

In 1992, Atkins reissued his book, with minor changes, notably the addition of a significant roster of vitamins, minerals and herbal supplements. But "the diet is pretty similar," says Atkins, who released yet another revision this year, again with minor changes.

Coincidentally, 1992 was the year the federal government introduced its Food Guide Pyramid, an eating plan with a bottom-heavy foundation recommending six to 11 daily servings of breads, cereal, rice and pasta.

Around the same time, the National Cancer Institute started its Five-a-Day campaign, a promotion aimed at getting Americans to eat more fruits and vegetables to cut their risk of developing cancer. Also during that period, nutrition experts were cautioning people to keep fats to no more than 30 percent of the calories in their diet. Food manufacturers went on a low-fat, no-fat binge. Carbohydrates were golden.

But something else happened, too. Americans got fatter than ever. A little more than half of the population is now considered overweight, according to government figures.

Low-fat eating has "been the dominant trend in dieting for the past decade, but its dominance hasn't, by and large, done a thing to take the pounds off," writes Atkins in "Dr. Atkins' New Diet Revolution."

"The low-fat, high-complex-carbohydrate approach has proven a failure," write physicians Michael Eades and Mary Dan Eades in "Protein Power."

The protein proponents' philosophy began to catch on, even though the reasons for America's expanding waistline are more complex than the popularity of the all-you-can-eat pasta and olive oil diet.

For one thing, despite all the low-fat hoopla, Americans are not eating less fat. From 1989 to 1995, daily fat consumption slightly increased, according to the U.S. Department of Agriculture. And calories went up at even a faster pace, says the USDA.

For example, there was a 13 percent increase in fat consumption among men 19 to 50 years old between 1990 and 1995, and a 21 percent increase in their total caloric intake over the same period, according to the USDA. In 1990 the average man ate 2,215 calories a day; in 1995, he was consuming 2,672. So no wonder people are getting fatter: They're eating more.

While sedentary lifestyles, restaurant-portion sizes and the ubiquitousness of food in America are all partly to blame, there's also a grain of truth in the failure of low-fat dieting--at least the way many people interpreted it. "People didn't understand that cutting fat also meant cutting calories," says Tallmadge, the dietitian. "Low-fat doesn't work if you're eating half a box of Entenmann's fat-free cake or having a big scoop of low-fat frozen yogurt every day for a snack."

And that's apparently what many people were doing. The increase in calories from 1990 to 1995, according to the USDA, came largely from people eating more carbohydrates, often in the form of grain products and soft drinks.

The protein proponents, however, are not concerned with calories. They say they have other reasons to blame carbohydrates for the increasing girth of the nation.

The Insulin Connection

The fundamental belief of Atkins and his bestseller colleagues is the notion that carbohydrates disrupt the balance of sugars and the natural hormone, insulin, that regulates them in the body, thus promoting fat storage and weight gain--a theory that the mainstream scientific community largely dismisses.

This hypothesis stems from a well-researched and accepted principle: When someone eats carbohydrates, the body breaks them down into simple sugars, or glucose. Then insulin, a hormone secreted by the pancreas, allows the circulating glucose to be used by the cells for energy. The more carbohydrates you eat, the more insulin is required.

The protein advocates go a step further and believe that eating too many carbohydrates can cause "insulin resistance," a condition in which the cells of the body resist insulin's attempts to get sugar out of the bloodstream. To get the job done, the pancreas secretes more and more insulin, but its action becomes less and less effective, creating a situation called hyperinsulinemia. In some people, this condition can lead to diabetes. But in others, the excess insulin turns the unconverted glucose into fat, rather than energy, say the protein proponents.

Most nutrition researchers agree that an excess of carbohydrates will be converted by the body into fat, but not because of insulin resistance. Instead it is a function of eating more than the body can absorb. Excess calories of any kind--whether they come from carbohydrates, fat or protein--will eventually be converted by insulin into body fat, says Howard Lando, associate clinical professor of medicine at George Washington University.

"Insulin doesn't make you fat. Calories make you fat," agrees Gerald Reaven, an emeritus professor of medicine at Stanford University.

Still, there are bits of accepted nutritional theory in the protein books' contentions, according to scientists. Insulin resistance and hyperinsulinemia are real conditions, as is Syndrome X, a term coined by Reaven for a cluster of problems in which people are insulin-resistant and have high levels of blood fats called triglycerides, high blood pressure and low levels of the "good" (HDL) cholesterol.

But it has never been demonstrated that these conditions cause people to be overweight, says Reaven. It's more likely the other way around. Being overweight causes the problems, he says. When people lose weight, in fact, these conditions often reverse themselves.

In addition, most researchers believe that only a small percentage of the nondiabetic population is insulin-resistant. "All the fancy talk about insulin has really nothing to do with the issue," says Jeremiah Stamler, professor emeritus at Northwestern University Medical School. "The hormone has been around for millennia. Mass obesity is a recent problem." The real issue, says Stamler, is that "we have a culture overwhelmed by food as we become more and more sedentary."

The high-protein diet books, however, assume that insulin resistance is more common and the diet regimen of steak and eggs is being marketed to the masses. Atkins, for example, is adamant that insulin causes people to be overweight. "I can't imagine anyone disagreeing on that," he said in an interview. Insulin as a fat-producer is "as well established a fact as a fever causes an elevated temperature."

Let Them Eat Bacon and Eggs

The low-carbohydrate diets prompt strong warnings from critics, who argue that the dearth of fiber and the overload of fat can have tremendous effects on long-term health. They point to population studies showing some benefits against cancer and heart disease from foods high in fiber, especially fruits and vegetables that contain a number of beneficial nutrients and vitamins. But the most serious consequence of high protein diets, they fear, is the rise in fat consumption, which has long been linked to cardiovascular disease.

To be sure, not all of the protein books are alike; their programs vary--sometimes widely--in the amount of carbohydrates they allow as well as their recommendations about fat.

Atkins's book seems to be one of the more permissive when it comes to consuming fat and the most restrictive when it comes to carbohydrates. In "Dr. Atkins New Diet Revolution," for example, there's a recipe for Swiss Snack, which consists of wrapping bacon strips around cubes of Swiss cheese and deep frying them in hot oil. The recipe, which serves one, calls for four strips of bacon and a quarter-pound of cheese.

Even though the federal government and every major health organization assert that diets high in fat are linked to heart disease, Atkins writes that there is "compelling evidence" that points in the opposite direction.

Part of the evidence he uses to bolster his point is that in 1910, a coronary event was a "rare find," and that by 1970, it was the leading cause of death in the United States. During this same period, he says, the intake of animal fat fell while the intake of sugars and refined carbohydrates went up.

Art Campfield, a professor of medicine at the Center for Human Nutrition at the University of Colorado, counters that the reason people had less heart disease in the early part of the century is that they didn't live long enough to get it. Nowadays, people are not only living longer, but diagnostic techniques are much better, he said. In addition, a century ago, Americans got much more exercise to counter the effect of fat in the diet. People's jobs consisted largely of physical activity "instead of sending e-mails," says Campfield.

Bonnie Liebman, director of nutrition for the Center for Science in the Public Interest (CSPI), is dumbfounded that the high-protein regimes have caught on. "With all the evidence that saturated fat promotes heart disease, it's almost unbelievable to me that people could successfully tell people to eat bacon, eggs, ground beef, cheese and cream," she says. "It really shows that people care more about how they look than how healthy they are."

But Adkins responds in his most recent book that his diet plan has been the subject of a "constant barrage of misinformation repeatedly disseminated through the media" in an effort to convince consumers that the diet is dangerous. People who follow the diet have been "forced to consider the possibility that one person may be right and the rest of the world wrong." He argues that much of the criticism comes from economic interests because many of the foods his diet uses "bring minimal profits to the food industry."

True Believers

Many people swear by their high-protein diets. "It's right for me," says a Washington area woman who reports having lost 15 pounds in two months on the Atkins diet while loading up on steak with bearnaise sauce and broccoli with "hollandaise dripping all over it." But she also lost something else: the ability to have a normal bowel movement.

Because she stayed on the "induction" phase of the diet--a two-week segment that prohibits all fruits, all whole grains and many vegetables--she was ingesting very little fiber. The result was a nonfunctioning bowel, which required medical attention. She underwent a colonoscopy and was treated with prescription medications.

But the woman, a 53-year-old senior government executive who asked that her name not be used, returned to the diet after her bowel problem was solved. She had to abandon it once more after she started getting constipated again, but she said it "breaks my heart . . . I'm a believer."

Jesse Reuben, a 63-year-old semi-retired attorney from Potomac, is a believer, too. About a year ago, Reuben lost 20 pounds in four months on the Atkins diet. "I think Dr. Atkins has it right," says Reuben, who has learned how to make "great fried eggs and omelets" and is delighted that he can have "pastrami and corned beef 'til the cows come home--but just not on a sandwich." Reuben says his blood cholesterol level is unchanged at 220mg/dl, so his doctor told him the diet was fine although he "wouldn't offer any endorsement." And he says that so far he has gained back only about five pounds.

All the weight came back on Jamey Bowers, a 28-year-old graphic designer in the District. Bowers followed the "Sugar Busters!" plan for about a month, losing nine pounds in the first two weeks. But then he started to cheat, adding sugary foods back to his diet. "When you cheat on that diet, it's almost even worse," says Bowers, who said he had gotten used to eating extra helpings of protein-rich nuts and cheese. Then, not only was he eating sugary foods again, but twice the fat as before. He easily regained the nine pounds.

Long-Term Loss

While the high-protein books are full of testimonials, there's no research that demonstrates these diets keep weight off. Even Atkins admits that there is "no formal documentation" of long-term weight loss on his diet, although he says that there are "several outsiders" who want to study it.

Of course, losing weight and keeping it off is a challenge for any dieter, and up until recently, there was little documentation that any regime did the trick. But two pieces of information shed at least some light on long-term loss. The National Weight Control Registry, a database run out of the University of Pittsburgh, keeps track of people who have maintained big weight losses. In a study published in the American Journal of Clinical Nutrition in 1997, the registry tracked the dietary intakes of its members, 629 women and 155 men, who had lost an average of 66 pounds and kept at least 30 pounds of it off for five years.

The study found that "as a whole, they weren't eating a high-protein diet," says Rena Wing, principal investigator for the registry and professor of psychiatry at both Brown University and the University of Pittsburgh. On average, the participants received only 19 percent of their calories from protein during the previous year. Fat constituted 24 percent of calories, carbohydrates 56 percent.

Similarly, in her book "Eating Thin for Life" nutritionist Anne Fletcher delved into the habits of 208 people who had lost an average of 64 pounds and maintained the loss for an average of 11 years. Fletcher said she found that "basically, they're eating the opposite of a high-protein, low-carbohydrate diet." When she asked the participants to describe their eating habits, "low-fat was the top response," she said, followed by "eating less meat." In her survey, the successful losers told her they also eat more fruits and vegetables and lots of grain foods.

Another important point that the high-protein diet books don't focus on, says Fletcher, is that "losing weight and keeping it off have to do with way more than food." Since many people who struggle with weight are often eating for emotional reasons, the successful losers learned to get pleasure from other things in life, such as exercise, new hobbies or more fulfilling jobs. They developed a "healthy selfishness," says Fletcher. And they also accepted the fact that they couldn't go back to their old way of eating.

The Diet Book Universe

Still, for many Americans, losing weight and keeping it off is a lifelong, wrenching experience. Rational people go on irrational diets because "they're desperate," says Kelly Brownell, director of Yale University's Center for Eating and Weight Disorders. "If you're a person with an overweight body living in a thin-obsessed world . . . something that offers a miracle is highly attractive."

Diet books offer that miracle through the bestseller formula: "easy, rapid weight loss; the opportunity to eat your favorite foods and some scientific 'breakthrough' that usually doesn't exist," says Brownell.

The sad thing, says Liebman of CSPI, is that "people keep believing that the magic bullet is just around the corner . . . if they only eliminate food 'x' or combine foods 'a' and 'b,' or twirl around three times before each meal."

So the protein plans offer yet another magic bullet, an alternative to the hard work of eating fewer calories and exercising more.

But losing weight the sensible way certainly isn't impossible--or boring. After all, which would you rather do: Just eat turkey for Thanksgiving? Or help yourself to all the trimmings as well and take a brisk walk after dinner?