I have recently investigated the Paleolithic diet literature and a number of basic issues interest and puzzle me. First, it seems that to identify with a particular lifestyle or practice, one requires a reasonable body of empirical knowledge of the aforementioned. It appears that this basic condition is not satisfied in the case of aspiring modern day Paleolithic nutritional adepts. The available information on Paleolithic peoples is so scanty that it seems specious to believe that one can follow their nutritional practices with more than a modicum of accuracy. The picture we have of contemporary hunter-gatherers suggests that few conclusions can be drawn due to the high variability of nutritional patterns across different populations, in addition to the difficulty of the contaminating influences of contact with industrial and post-industrial cultures.

 Two of the assumptions that appear to be held in common by most who write about the Paleolithic diet is that there was  generally an absence of grains and dairy products (1). Furthermore, it is often suggested that there has not been a long enough evolutionary time period to physiologically adapt to the metabolic requirements of these substances, which has often led to the  breakdown of healthy  functioning (2). Experimental and anthropological investigations of pathology and longevity  suggest a picture which appears somewhat at variance with some of the current Paleolithic practitioners' beliefs. With regard to anthropological evidence, it appears that modern day Hunza and Vilcambas peoples demonstrate considerable disease-free extended life spans (3). Although problems arise ascertaining the exact ages of the the older members of Hunzaland, evidence suggests an absence of cardiovascular disorders (4).  Both of these populations are agricultural and subsist on a very restricted calorie diet which includes grains, legumes, dairy and very small quantities of meat. Regarding experimental  research, the most robust finding seems to be that a calorie restricted diet is positively correlated with longevity and reduced rates of pathology (5). No other nutritional variables appear to be reliably associated with longevity. With regard to pathology, a high intake of red meat has been associated quite consistently with the development of cancers (6).

         Perhaps the Paleolithic diet (if there is such a thing?), in the form of a relatively high fat and protein intake by today's standards, was evolutionarily selected because it was the most effective  to develop  the human form for the first two decades of life with the goal of effective reproduction. It may be that the genetic agenda has loaded the psychobiological developmental trajectory towards reproductive fitness rather than longevity. A diet higher in protein and fat, and lower in carbohydrates than that promulgated by current  mainstream  thinking, may have been necessary to ensure the viability of the human species, but may be out of step with current conditions. It hardly seems that reproductive prowess is a trait useful  in the face of the current population explosion and the ever dwindling food supplies for the planet.

One wonders if instead of chasing the chimera of 'Paleolithic man', we should not be looking more carefully  at the evidence from the 20th century. Any comments on these points would be appreciated.


References

1. DeVany, A. "Evolutionary Fitness," 14, 1997.
2. Eaton, S.B ., Shostak, M., et al. The Paleolithic Prescription: A Program of Diet & Exercise and a Design for Living: 41. New York: Harper & Row, 1988.
3. Leaf, A. National Geographic, 143:93, 1973.
4. White, P.D., & Toomey, E.G. , American Heart Journal, Dec., 1964.
5. Walford, R.L. & Weindruch, R. The Retardation of Aging and Disease by Dietary Restriction. Springfield, Illinois Charles C. Thomas, 1988.
6.    Campbell, T. Colin; Chen, J"Diet and chronic degenerative diseases: perspectives from China." American Journal of Clinical Nutrition, vol. 59,  1153S-1161S. , 1994.