A group of doctors, after reviewing earlier studies of meat consumption and disease, has pub-lished a report arguing that the yearly national health-care costs of eating meat are comparable to the estimated $50 billion spent each year to treat illnesses related to smoking.

A spokesman for the American Medical Association, however, said he had "very serious reservations" about the methods used to come to those conclusions.The authors of the analysis, Dr. Neal D. Barnard, Dr. Andrew Nicholson and Jo Lil Howard, are all members of the Physicians Committee for Responsible Medicine, an organization in Washington that promotes vegetarianism. They linked regular consumption of red meat and poultry, in particular, to significant increases in the risks of developing high blood pressure, heart disease, diabetes, gallbladder disease, overweight and resulting osteoarthritis, food poisoning and cancers of the colon, lung, ovary and prostate.

The analysis was published in the current issue of Preventive Medicine, a peer-reviewed journal of the American Health Foundation, a nonprofit organization devoted to research on preventive health measures. The researchers estimated the health costs of the nation's current omnivorous diet at $28.6 billion to $61.4 billion a year.

In an accompanying editorial, Dr. Randall White, a psychiatrist in Atlanta, and Suzanne Havala, a registered dietitian, said "the money we spend to treat these conditions, often called diseases of affluence or overnourishment, could help meet the basic health care needs of those currently uninsured."

In fact, the authors of the journal report concluded, "the combined medical costs attributable to smoking and meat consumption exceed the predicted costs of providing health coverage for all currently uninsured Americans."

The report comes at a time when national nutrition and health experts are urging Americans to reduce their dependence on meat. The Eating Pyramid issued several years ago by the federal Department of Agriculture suggests two to three servings daily of a high-protein food like meat, poultry, fish, beans, eggs and nuts. It defines a serving as only two to three ounces of cooked meat, fish or poultry. Even the meat industry has become more tempered in its dining advice, suggesting that Americans choose lean, well-trimmed meats and four-ounce portions.

Furthermore, the new Dietary Guidelines for Americans, to be issued next month by a committee of the National Academy of Sciences, may for the first time report the health benefits of a vegetarian diet.

White, who said he had been a vegetarian for 17 years, and Havala, who is a consultant to the Baltimore-based Vegetarian Resource Group, which promotes vegetarianism, maintain that "the cost of the American way of eating has become unsustainable." While the diseases of affluence and overnourishment cited in the journal report occur among vegetarians and nonvegetarians alike, "they occur at lower rates among those who eat fewer animal products," the editorial writers noted.

The researchers did not offer physiological explanations for these findings beyond pointing out that "when meat is included in the diet, plant products are necessarily reduced." They added, "The health effects of an omnivorous diet may result from the presence of meat, the displacement of plant foods, or both."

Diets containing meat are usually higher in fat, particularly artery-damaging saturated fat, and higher in calories. Plant foods are less calorically dense and they are rich sources of vitamins, minerals, fiber and other beneficial substances.

In general in the studies, about half the people were vegetarians, most of whom consumed eggs and dairy products but not red meat, fish and poultry. However, in their smoking, exercise and alcohol consumption habits, all of which can strongly influence health, they were not notably different from the meat eaters studied.

Yet in every study examined, meat eaters had higher rates of costly and sometimes fatal health problems.

Dr. Roy M. Schwarz, group vice president for professional standards of the American Medical Association, said the study did not specify whether factors like age, sex and genetic history of the people covered in the studies had been taken into account.