[ I wrote the following as part of a "conversation" with a friend, but thought that folks on the list would have some perspectives on the topic.] Fat in the Paleolithic Diet There seems to be some controversy regarding the role of fat in the diet of Paleolithic humans. One reason for disagreement is that people tend to speak of a typical Paleo diet, when in fact it stands to reason that the diet differed considerably according to geography and climate. Diets of 20thC HGers certainly exhibit much diversity, with a large range in the relationship of plant and animal food in the diet, and in the types of animal food. In The Paleolithic Prescription (PP), Eaton et al. construct an average diet for Late Paleolithic humans that has 21% of total calories coming from fat (slightlyly less than half from animal sources). The amount of animal fat is based on the average fat content of 43 species of present-day wild game from three continents. The average is 4.3%, with a range from around 1-8%. This is far below choice beef sirloin at 27%. One question is: to what extent does the composition of present-day wild game approximate that of the game hunted by Paleo humans? Many of the animals hunted by Paleo humans -- at least in Europe and North America -- no longer exist. It seems that here too geography and climate would play a major role. Much of the period in which homo sapiens sapiens has lived (roughly the last 100,000 years) was characterized by very cold climate, at least in the temperate regions. Since fat is an insulator, it seems likely that at least some of the hunted animals in these regions had a higher fat content than that of present-day wild game, but probably still much less than domesticated cattle. It is also worth bearing in mind that modern humans arrived relatively late in colder regions such as Northern Europe and Siberia (beginning around 35,000 years ago), and much of the pre-agric human population adapted to wild game that was available in the tropics (presumably less fatty?). In their article The Cave Man Diet (PPNF Health Journal, Vol. 21, No. 2), Fallon and Enig argue that the Paleo diet was both higher in fat and higher in saturated fat than the typical diet proposed by Eaton et al. Drawing on the collection Ice Age Hunters of the Rocky Mountains, they list a number of animals that were hunted, and say that many of them are fatty animals. However, two animals that they cite as fatty (bison and beaver) are listed by Eaton et al. as having fat content of only 3.8% and 5.1% respectively. However, Fallon/Enig also refer to the cave mans preference for the fatty portions of his kill. The fat contents cited by Eaton et al. refer to portion of fat in muscle meat. But other portions (organs, brains, tongue, marrow) are prized by many 20thC HGers, and these are usually higher in fat content. Eaton et al. also argue that the animal fat in the Paleo diet was low in saturated fat compared to that of domesticated red meat. This too is based on the fat content of present-day wild game. Saturated fat as % of all fatty acids is generally in the 60-70% range, well below domestic beef/pork/veal. Fallon/Enig report similar data. So, have Eaton et al. understated the role of fat in the Paleo diet? It seems that may be so with respect to people living in Europe and No. America, and perhaps the colder regions of Asia. Plant foods were less abundant in these regions, so animal foods played a larger role than indicated by the typical diet in the PP. And it makes sense that people in cold climates would want to get as much calorie-dense fat as possible. For Paleo people in other regions who lived in a less cold climate, perhaps the role of fat suggested in the PP is closer to the truth? Stephen Meyers Berkeley, CA