Why Nutrition Science is Bunk

The people who run the Harvard long-term Nurses' Health Study have been in the news again lately, claiming that red meat will kill you and chocolate will make you thinner. These claims are perfect examples of what is technically known as crap. What the Harvard people keep doing is finding correlations, e.g., the 20% of their subjects who eat the most red meat had a 20% greater chance of dying over the course of the study. Then they make causal claims. Gary Taubes:

I have pointed out that every time that these Harvard researchers had claimed that an association observed in their observational trials was a causal relationship—that food or drug X caused disease or health benefit Y—and that this supposed causal relationship had then been tested in experiment, the experiment had failed to confirm the causal interpretation—i.e., the folks from Harvard got it wrong. Not most times, but every time. . . .

This is an issue about science itself and the quality of research done in nutrition. Science is ultimately about establishing cause and effect. It’s not about guessing. You come up with a hypothesis—force x causes observation y—and then you do your best to prove that it’s wrong. If you can’t, you tentatively accept the possibility that your hypothesis might be right. In the words of Karl Popper, a leading philosopher of science, “The method of science is the method of bold conjectures and ingenious and severe attempts to refute them.” The bold conjectures, the hypotheses, making the observations that lead to your conjectures… that’s the easy part. The ingenious and severe attempts to refute your conjectures is the hard part. Anyone can make a bold conjecture. (Here’s one: space aliens cause heart disease.) Testing hypotheses ingeniously and severely is the single most important part of doing science.

The problem with observational studies like the  ones from Harvard and UCSD that gave us the bad news about meat and the good news about chocolate, is that the researchers do little of this. The hard part of science is left out, and they skip straight to the endpoint, insisting that their causal interpretation of the association is the correct one and we should probably all change our diets accordingly.

That "scientists" who hold positions at Harvard can get away with spewing garbage like this says something rather disturbing about American academic life.