Here’s a nice essay about the Women’s Health Initiative, a nine-year mega-million-dollar experiment to measure the effect of “healthy eating” especially a low-fat diet.
48,835 postmenopausal women . . . were randomly assigned . . . to either their regular unrestricted diet or to a “healthy” diet that was low-fat (20% fat) and high fiber, with at least 5 servings of fruits and vegetables, and 6 servings of grains a day. The “healthy” eaters endured an “intense behavioral modification program by specially trained and certified professionals” to keep them on their diets. While they backslide a little, they did surprisingly well in sticking to the diet — as good as dietary prescripts will ever get and money can buy — at a cost of $8,498 spent per person!
Oops, no effect.
I conclude two things: 1. People in charge of spending vast sums on nutrition research don’t know very much about what constitutes a healthy diet. 2. The same people know very little about how to do experiments. The most basic lesson is to do the smallest experiment possible.
Sandy Szwarc, the author of this essay, concludes:
When we enjoy a variety of foods from all of the food groups — as most everyone naturally does when they’re not trying to control their eating — and trust our bodies, we’ll get the nutrients we need to prevent deficiencies. And that is the only thing that nutritional science can credibly support.
There is some truth to this, both (a) we instinctively eat to avoid certain deficiencies and (b) nutrition science has found conclusive evidence that we need certain chemicals. But she is quite wrong in the sense that most Americans appear to suffer from huge omega-3 deficiencies (my posts about this). Many of them, probably most of them “enjoy a variety of foods from all of the food groups.”
Thanks to Dave Lull.