The best-fitting model for predicting BMI (at 95% confidence)? Drum roll please. Three variables made the cut.
- Eating more wheat flour (beta = 0.48, p<0.001)
- Eating more polyunsaturated fat (beta = 0.44, p<0.001), and
- Eating fewer green vegetables (beta = -0.29, p<0.01).
This model has an r-squared value of 0.53, meaning it predicts a little over half of the variation in BMI—at least in theory. That’s actually pretty high, considering we haven’t directly factored things like physical activity into the equation.
Interesting, eh? All animal foods and total dietary fat, by the way, were completely insignificant in terms of BMI.
Of course, there could be other variables involved that the China Study didn’t cover. Were the higher-BMI folks also more heavily muscled (perhaps from more physical labor), increasing their body weight but not body fat? Are the wheat eaters, some of whom are ethnic minorities in China (especially Turkic and Mongolian), genetically “bigger” than the Han Chinese? There are plenty of unknowns, and alas, no way to clarify them based on this data.
I guess we’ll leave it as a question mark for now.
Grain damage: Do other studies back it up?
But don’t those peer-reviewed, scientific studies tell us wheat is healthy? Alas, the vast majority of studies on grains—especially wheat—showcase at least one of the following problems:
- They look at the effects of whole grains versus refined grains—not whole grains versus the same diet with no grains at all.
- Study subjects increase their consumption of whole grains, and this displaces some portion of yuckfoods (processed junk, white-flour products, sugary things, and so forth). As a result, it’s hard to tell whether any health perks are due to the addition of whole grains, or from the reduction of truly-awful-for-you foods. This is particularly true in studies that scout out disease patterns in populations rather than controlled studies that measure specific changes that occur with the addition of whole grains.
- They don’t adequately account for other factors that often accompany whole-grain consumption, like a greater level of health consciousness, more exercise, other positive diet choices, and so forth.
However, a few gems are lurking in the massive slush-pile of irrelevant studies. This one’s pretty doggone interesting, and it’s from all the way back in 1959: “Comparisons of atherogenesis in rabbits fed liquid oil, hydrogenated oil, wheat germ and sucrose.” You can click on that for the full-text PDF.
As you might guess from the title, this study examines the effects of diet on the development of atherosclerosis—AKA hardening of the arteries. The researchers took cholesterol-infused rabbit food and supplemented it with liquid corn oil (yuck), hydrogenated corn oil (double yuck), wheat germ (mystery murderer?), and sucrose (sweet poison!). Sorry, I dig hyperbole. Anyway, part of the goal was to create an experiment testing the hypothesis that “the geographic differences in the incidence of coronary disease might be related to selective hydrogenation of polyunsaturated fatty acids or to degermination of cereals.”
So now, the moment of truth: Which group had the most severe atherogenesis? Perhaps the one fed the nasty hydrogenated oil, as hypothesized? Ladies and gentlemen, place your bets. From the article:
The most severe atherogenesis occurred in the animals on the wheat germ diet.