I SCIENTIFIC REDUCTIONISM 271 many people still regarded the report as cataloging the specific effects of individual nutrients The nutrient that our committee focused on the most was fat The first gUideline in the report explicitly stated that high fat consumption is linked to cancer, and recommended reducing our fat intake from 40% to 30% of calories, although this goal of 30% was an arbitrary cutoff point The accompanying text said, "[Tlhe data could be used to justify an even greater reduction However, in the judgment of the committee, the suggested reduction is a moderate and practical target, and is likely to be beneficial." One of the committee members, the director of the United States Department of Agriculture (USDA) Nutrition Laboratory; told us that if we went below 30%, consumers would be required to reduce animal food intake and that would be the death of the report At the time of this report, all of the human-based studies showing fat to be related to cancer (mostly breast and large bowel) were actually showing that the populations with more cancer consumed not just more fat, but also more animal-based foods and less plant-based foods (see chapter four) This meant that these cancers could just as easily be caused by animal protein, dietary cholesterol, something else exclUSively found in animal-based foods, or a lack of plant-based foods (discussed in chapters four and eight) But rather than wagging the finger at animal-based foods in these studies, dietary fat was given as the main culprit I argued against putting the emphaSiS on specific nutrients in the committee meetings, but only with modest success (It was this point of view that landed me the expert witness opportunity at the FTC hearings.) This mistake of characterizing whole foods by the health effects of specific nutrients is what I call reductionism For example, the health effect of a hamburger cannot be simply attributed to the effect of a few grams of saturated fat in the meat Saturated fat is merely one ingredient Hamburgers also include other types of fat, in addition to cholesterol, protein and very small amounts of vitamins and minerals Even if you change the level of saturated fat in the meat, all of the other nutrients are still present and may still have harmful effects on health It is a case of the whole (the hamburger) being greater than the sum of its parts (the saturated fat, the cholesterol, etc.) One scientist especially took note of our focused critique of dietary fat, and decided to test the hypothesis that fat causes breast cancer in a large group of American women He was Dr Walter Willett of the 272 THE CHINA STUDY Harvard School of Public Health, and the study he used is the famous Nurses' Health Study Starting in 1976, researchers at the Harvard School of Public Health had enrolled over 120,000 nurses from around the country for a study that was intended to investigate the relationship between various diseases and oral contraceptives, post-menopausal hormones, cigarettes and other factors, such as hair dyes Beginning in 1980, Professor Willett added a dietary questionnaire to the study and four years later, in 1984, expanded the dietary questionnaire to include more food items This expanded dietary questionnaire was mailed to nurses again in 1986 and 1990 Data now have been collected for over two decades The Nurses' Health Study is widely known as the longest-running, premier study on women's health It has spawned three satellite studies, all together costing $4-5 million per year When I give lectures to health conscious audiences, upwards of 70% of the people have heard of the Nurses' Health Study The scientific community has followed this study closely The researchers in charge of the study have produced hundreds of scientific articles in the best peer-reviewed journals The design of the study makes it a prospective cohort study, which means it follows a group of people, a cohort, and records information on diets before disease events are diagnosed, making the study "prospective." Many regard a prospective cohort study as the best experimental design for human studies The question of whether diets high in fat are linked to breast cancer was a natural outgrowth of the fierce discussion going on in the mid1970s and the early 1980s High-fat diets not only were associated with heart disease (the McGovern dietary goals), but also with cancer (the Diet, Nutrition and Cancer report) What better study to answer this question than the Nurses' Health Study? It has a good deSign, massive numbers of women, top-flight researchers and a long follow-up period Sounds perfect, right? Wrong The Nurses' Health Study suffers from flaws that seriously doom its results It is the premier example of how reductionism in science can create massive amounts of confusion and misinformation, even when the scientists involved are honest, well intentioned and positioned at the top institutions in the world Hardly any study has done more damage to the nutritional landscape than the Nurses' Health Study, and it should serve as a warning for the rest of science for what not to 273 SCIENTIFIC REDUCTIONISM CARNIVOROUS NURSES In order to understand my rather harsh criticism, it is necessary to obtain some perspective on the American diet itself, especially when compared with the international studies that gave impetus to the dietary fat hypothesis Americans eat a lot of meat and fat compared to developing countries We eat more total protein, and even more Significantly, 70% of our protein comes from animal sources The fact that 70% of our total protein comes from animal sources means only one thing: we are consuming very few fruits and vegetables To make matters worse, when we eat plant-based foods , we eat a large amount of highly processed products that often have more added fat, sugar and salt For example, the United States Department of Agriculture (USDA) national school lunch program counts French fried potatoes as a vegetable! In contrast, people in rural China eat very little animal foods; they provide only about 10% of their total protein intake The striking difference between the two dietary patterns is shown in two ways in Chart 14.1 These distinctions are typical of the dietary differences between Western cultures and traditional cultures In general, people in Western countries are mostly meat eaters, and people in traditional countries are mostly plant eaters So what about the women in the Nurses' Health Study? As you might guess, virtually all of these women consume a diet very rich in animalbased foods, even richer than the average American Their average protein intake (as % of calories) is around 19%, compared with a U.S CHART 14.1: PROTEIN INTAKE IN THE U.S AND RURAL CHINA8 >, ro ~ ro +' f: c ·w e Cl 100 ~ 80