In the case of the fat-cholesterol hypothesis of heart disease, there has always been considerable skepticism of the hypothesis and the data. Why this skepticism is rarely made public is a major theme of this book. In fact, skeptics have often been attacked or ignored, as if disloyal at time of war. Skepticism, however, cannot be removed from the scientific process. Science does not function without it.

An underlying assumption of this book is that the evolution of medical science has suffered enormously, although unavoidably, by the degree of specialization needed to make progress. “Each science confines itself to a fragment of the evidence and weaves its theories in terms of notions suggested by that fragment,” observed the British mathematician and philosopher Alfred North Whitehead. “Such a procedure is necessary by reason of the limitations of human ability. But its dangers should always be kept in mind.” Researchers and clinical investigators by necessity focus their attention on a tiny fragment of the whole, and then employ the results of other disciplines to extend the implications of their own research. This means that researchers have to take on faith the critical acumen and scientific ability of those researchers whose results they are borrowing, and, as Whitehead noted, “it will usually be the case that these loans really belong to the state of science thirty or forty years earlier.”

This problem is exacerbated in the study of nutrition, obesity, and chronic disease because significant observations emerge from so many diverse disciplines. Indeed, the argument can be made that, to fully understand obesity alone, researchers should have a working familiarity with the literature in clinical treatment of obesity in humans, body-weight regulation in animals, mammalian reproduction, endocrinology, metabolism, anthropology, exercise physiology, and perhaps human psychology, not to mention having a critical understanding and familiarity with the nuances of clinical trials and observational epidemiology. Most researchers and clinicians barely have time to read the journals in their own subspecialty or sub-sub-specialty, let alone the dozens of significant journals that cover the other disciplines involved. This is a primary reason why the relevant science is plagued with misconceptions propagated about some of the most basic notions. Researchers will be suitably scientific and critical when addressing the limitations of their own experiments, and then will cite something as gospel because that’s what they were taught in medical school, however many years earlier, or because they read it in The New England Journal of Medicine. Speculations, assumptions, and erroneous interpretations of the evidence then become truth by virtue of constant repetition. It is my belief that when all the evidence is taken into account, rather than just a prejudicial subset, the picture that emerges will be more revealing of the underlying reality.