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?"
Except there's good evidence that this is not true. All calories are not equal: fat, protein and carbs are different. Your body is not a furnace that burns things for their raw energy content. (Which is how calories are measured: according to a calorimeter, coal has lots of calories, but your body would not agree.)
One example is alcohol. There's evidence that the calories in wine and liquor do not cause the weight gain that the equivalent amount of calories of beer will do, and there's some evidence that alcohol consumption can cause weight loss in women. The "diet science" you are quoting is just the sort of thing Adams is talking about.