Nonfiction — print. Simon & Schuster, 2014. 480 pgs. Library copy.
Subtitled “Why Butter, Meat and Cheese Belong in a Healthy Diet”, Teicholz’s book documents how the low fat diet became the national – and thanks to America’s outsized influence on that global food system, international – nutrition diet nearly sixty years ago. With rates of heart disease skyrocketing, nutritionists and scientists assumed correction meant causation decreeing that fat, especially saturated fat, were to blame. Yet while rates of heart disease have declined over the past six decades, rates of obesity have increased tremendously and the general health of the American population has declined even as more and more Americans adhere to a low fat diet.
“A review in 2008 of all studies of the low-fat diet by the United Nation’s Food and Agriculture Organization concluded that there is ‘no probable or convincing evidence’ that a high level of fat in the diet causes heart disease or cancer. And in 2013 in Sweden, an expert health advisory group, after spending two years reviewing 16,000 studies, concluded that a diet low in fat was an ineffective strategy for tackling either obesity or diabetes.” (pg. 172)
The assumption of causation were based on epidemiological studies – that is, the study of people’s behaviors and eating habits – yet the major studies cited in support of the low fat diet would not pass a basic research methods course. Interviewees were studied during Lent when their eating habits would change based on religious edict; interviewees were overwhelming middle-age males. And the statistical significance of their conclusions were well within the acceptance rate – a 1.9 significance in a study that admitted to having a plus or minus 2 points variation.
The studies were also some of the first published in the United States giving the authors an inflated stature within the medical community such that their studies went unquestioned for decades. New studies or those that seemed to contradict the connection between a high fat diet and poor health were criticized in the opinion pages of journals of lower ranking and were largely ignored by the National Institutes of Health and the American Heart Association, which maintained close ties with the original research, Ancel Keys, who determined low fat diets reduced the instances of heart disease.
High fat diets have also been associated with a higher rate of breast cancer; a tenuous link largely disproven by Walter Willet’s 1987 Nurses’ Health Study, which found that the more fat (particularly saturated fat) the nurses ate, the less likely they were to develop breast cancer. Willet’s study was dismissed by the director of the National Cancer Institute in an opinion piece where he argued that data from rats proved a high fat diet induced mammary tumors. Yet the director failed to mention that the most effective fats for growing tumors were polyunsaturated – the same fats found in vegetable oils Americans were being encouraged to use instead of animal-based fats (pg. 167).
This is one of the few examples of a study in which women were studied because, as Teicholz explains, women were excluded from most clinical and epidemiological studies because the heart disease epidemic initially affected more men than women. Yet this exclusion has continued with women representing only 20 percent of participants in studies until 1990 and only 25 percent thereafter (pg. 159). Yet women are expected to follow advice based on studies involving rats or men.
Children are also feed a low-fat diet; 88 percent of mothers in 1995 believed a low-fat diet was “important” or “very important” for their infants and 83 percent said they sometimes or always avoid giving fatty foods to their children (pg. 150). Yet there is no scientific evidence to back up the suggestion that children should avoid fats, particularly saturated fats.
Avoiding these fats means Americans have focused on utilizing vegetable oils and replaced the fats from meat, eggs, milk, and cheese in their diets with more carbohydrates, the bases of both the USDA’s food pyramid and the Mediterranean Diet. Carbohydrates wreak havoc on the body’s ability to process insulin, which then causes the body to store fat rather than burn it and leads to increased waist lines.
The anti-carbohydrates diet was, of course, made famous by Robert C. Atkins , and Teicholz spends a chapter examining how the medical establishment responded to Atkins diet. She points out some of the flaws with the diet and the lack of studies to back up its assertions, but she seems to be largely in favor of the diet over the heavily championed Mediterranean Diet, which she also focuses on in its own chapter.
Obviously, I learned quite a bit from this book. It turned everything I have ever read on the topic of obesity and the American food system on its head, and I would heartily recommend it on that point alone. It is not always the easiest book to follow – a bit repetitive, a bit unclear – and there are some chapters that could have been trimmed or cut all together to made it a clearer read. Teicholz engages in some of the same manipulation of (bad) data to fit her argument, but those moments are rather obvious. And beyond the implications for personal and public health policy, I think the book would make an interesting addition to any college research methodology class because of the questions it raises about how science and statistics can be fallible and manipulated.