Most of our major causes of death and disability in the United States today are a direct result of the standard American diet. It would be bad enough if people knew that their eating habits were endangering their health. What’s worse is that people are harming themselves unknowingly, by eating foods that they have been told are good for them and even essential to good health. This tragedy goes on partly because people don’t want to hear bad news about their bad habits. However, I think that a major part of the problem is that most Americans have had a poor science education and most of their doctors have had poor training in nutrition. As a result, they don’t know how to make sense of the scientific research that is now so easily available to them through the Internet. As a result, they are easily fooled by people who call themselves skeptics but really should be classified as deniers.
In 2007, Dr. Daniel Steinberg published The Cholesterol Wars: the Skeptics Vs. the Preponderance of Evidence. That book provides an excellent critique of the arguments put forth by the “cholesterol skeptics,” who are people who deny the “lipid hypothesis”: the idea that high levels of cholesterol are a major causative factor in heart disease. He summed up the problem as follows:
As we recount the advances in knowledge that ultimately proved the correctness of the [lipid] hypothesis, we will examine the criticisms offered by the opponents. There were several, but perhaps the major difference between the “convinced” and the “unconvinced” was that the latter were unwilling to look at the totality of the evidence, i.e., to evaluate the related by relevant separate contributions coming from different sources—from experimental animal studies, from epidemiologic studies, from genetic analyses, and from clinical observations. Each of these fields, approaching the problem from different directions, contributed solid evidence strongly implicating hypercholesterolemia as a major causal factor in atherosclerosis and its clinical expression. And they did so well before definitive clinical trials made the causal connection clear and unarguable. However, to the naysayers, any perceived weakness in any one line of evidence or any one clinical trial was considered sufficient to justify dismissing the hypothesis out of hand—and they were quick to point to anything that did not fit. It is true that in assessing the validity of a deductive hypothesis (if a then b), even a single discordant observation (a and not b) refutes the hypothesis. Such an uncompromising standard for refutation may be warranted, say, in the case of basic theories in physics, but that is not the case in medical science, which is only now inching its way toward membership in the hard sciences. In medicine we still deal with statistical hypotheses (if a then b with some probability c). Occasional discordant observations (a and not b) certainly weaken the proposed causal connection but do so only with some degree of probability, not absolutely.
Note: Dr. Steinberg was complaining that most people do not know the difference between a deductive and inductive argument. This difference is important, as I explain in my book Not Trivial: How Studying the Traditional Liberal Arts Can Set You Free. Schoolteachers in the United States have been discouraged from giving their students direct training in the classical trivium of grammar, logic, and rhetoric. The neglect of the trivium has had several serious consequences. One is poor reading comprehension and needless difficulty in learning foreign languages. Another consequence is that few people know how to make or interpret reasonable arguments. As a result, they are often unreasonable, often without realizing it.