Hugh Pickens writes:
Scott Adams of Dilbert fame writes on his blog that science's biggest fail of all time is 'everything about diet and fitness':
I used to think fatty food made you fat. Now it seems the opposite is true. Eating lots of peanuts, avocados, and cheese, for example, probably decreases your appetite and keeps you thin. I used to think vitamins had been thoroughly studied for their health trade-offs. They haven’t. The reason you take one multivitamin pill a day is marketing, not science. I used to think the U.S. food pyramid was good science. In the past it was not, and I assume it is not now. I used to think drinking one glass of alcohol a day is good for health, but now I think that idea is probably just a correlation found in studies.
According to Adams, the direct problem of science is that it has been collectively steering an entire generation toward obesity, diabetes, and coronary problems. But the indirect problem might be worse: It is hard to trust science because it has a credibility issue that it earned. "I think science has earned its lack of credibility with the public. If you kick me in the balls for 20-years, how do you expect me to close my eyes and trust you?"
I think if you compared the consensus among those health-professionals to the consensus among scientists studying health, you would have found them to be quite different. (snip)(For many of the examples cited in the rant, if you go back to an article from that time-period, you would find it painting a very different story from the media headlines.)
Fair enough; but where are Scott Adams' citations?
For many of the things the rant quotes, the "proof" that he's wrong is actually the fact that no one can point to a scientific study making the claim. E.g.:
- The whole "8 glasses of water a day" didn't come [snopes.com] from a scientific study.
- The various incarnations of the US food guides were not based purely on input from scientists, but rather have a long history of being co-opted by special interest groups [harvard.edu].
- The rant even notes "The reason you take one multivitamin pill a day is marketing, not science." I.e.: it was not the scientific consensus arguing for their relevance (see, e.g., this [nih.gov] for the scientific consensus: they usually won't do much good).
As for supporting my contention that scientific studies are cautious and tend to acknowledge limitations (especially compared to the media)... well, you can pick up just about any scientific medical journal. Here's an example, related to the rant's discussion of fatty acids making people fat: In Dietary Approaches to Obesity [soylentnews.org], the authors note: "...the optimal diet composition quality for weight loss is far from known. The major controversy seems to be between choosing low-fat or low-carbohydrate diets, with additional debates on the importance of the glycemic index and the amounts of dairy products and calcium. It is evident from many large, randomized trials that the "best diet" that can suit everyone has yet to be identified. The different options for low-calorie diets should be prescribed on an individual basis..."
Here's another example [bmj.com], related to alcohol consumption, from 14 years ago (presumably within the time-period decried by the rant?), noting: "...the effect of “moderate” alcohol consumption on overall health remains controversial" and "Genetic factors modify the effect of alcohol consumption on risk of CHD, resulting in population variability in the amount of benefit achieved from alcohol consumption" and then detailing the details about drinking patterns, gender, etc. This is quite different from the simplistic "alcohol good for health" Adams states.
More examples could be found, but actually Adams' rant is so vague and un-sourced that it's difficult to provide specific counter-evidence. He does not provide evidence that the scientific community was confidently supporting the take-home-messages he lists.