The paleoblogosphere is humming with excitement the past few days over the glorious work done by raw food blogger Denise Minger in her personal examination of the China Study, a large data set of epidemiology studies used by researcher T. Colin Campbell to formulate his book The China Study: The Most Comprehensive Study of Nutrition Ever Conducted and the Startling Implications for Diet, Weight Loss and Long-term Health. In it, Campbell comes to the conclusion that avoiding animal protein is the best way to avoid all sorts of diseases of civilization.
Denise's post uses the same China data set to implicate wheat as a major factor associated with heart disease and cancer, not animal protein. Kurt Harris of PaNu makes a point in his analysis of Denise's work that is the closest to my own struggles combing the literature - association studies are interesting, but troublesome. Conclusions from such studies should be viewed with a furrowed brow. "Hmmm, that's intriguing. I wonder why red-tailed baboons who eat less algae live longer than the red-tailed baboons who eat more algae? Why don't we do a prospective randomized controlled trial of red-tailed baboons and algae eating to sort that one out?" Because associations always come with confounding factors - turns out red-tailed baboons who eat algae love race car driving, and have you ever seen a baboon wearing a seat belt? Sophisticated statisticians will try to account for all these "confounding factors," but such a task can be simply impossible when examining a complex system such as society, or the biochemistry of the human body.
The psychiatric literature is loaded with brief, often useless, short-term randomized controlled studies of lesser and better quality and association studies. It seems the nutrition literature is even worse. Large, long prospective trials of good quality are horrendously expensive, and may take decades to do properly.
This is why I feel the healthiest and most sensible way to eat is based on an evolutionary paradigm, and that evolutionary-based lifestyle measures (though I haven't blogged too specifically about them yet, as the nutrition aspect is my primary personal interest, these measures would include regular exercise, meditation (as a proxy for the intense in-the-now concentration we used to use for hunting and gathering), proper sleep, working with the hands, and various other social/fun stress-reducing activities) are likely to be most effective for our modern, unsettled minds. It is not that there is a huge amount of science data backing that up - it is that until we have exhaustively proven otherwise (which so far, in my mind, we haven't), at least scientists can concede that our exceedingly complex human design is based on adaptations for our ancestors' lives.
For public health and sanity, I believe in an evolutionary viewpoint. And animal protein :)