In a recent post, Mary Enig & Sally Fallon solicited information
on the fat content of wild game animals.   My colleague, Boyd Eaton, has
previously summarized the fat content of lean game muscle meat (1), but
did not present data on total carcass fat content.
          Speth (2) has compiled data from 33 analyses of whole body fat
% of 11 different species of wild ungulates.   The mean value of 3.6%
fat is similar to other estimates (2-5%) based upon compiled data (3).
In contrast the total body fat content of a domesticated, grain fed
steer ranges between 33-40% (2).    In wild animals, the total fat
content changes seasonally (at higher latitudes it is lowest during late
winter and early spring, whereas in lower latitudes it is lowest during
the dry season).   During late summer & early fall, certain North
American species have been reported to have total fat levels as high as
17% (2), whereas some African species have been shown to have values as
high as 6% (2).  Stefansson (4) noted that "the largest slab of back fat
which I have seen taken from a caribou on the Arctic coast was from a
bull killed near Langton Bay early in September, the fat weighing 39
lbs".   Large caribou bull can weigh between 350-400lbs, so the
subcutaneous back fat of high northern ungulate species could
conceivably represent 10% of the total weight under the best of
conditions during early fall.   However, remember that after the rut and
into winter total fat % drops back down to an average of 1.3% (2) for
caribou.  This reduction of total fat percentage occurs for all tissues
except brain, and results mainly from reductions in subcutaneous storage
fat.   Wild ungulates unlike domesticated cattle do not store depot fat
(saturated primarily) intra-muscularly (i.e. marbling)   Thus, it is
apparent that high levels of total fat intake could have only occurred
seasonally (perhaps 2-4 months) in early man dependent upon wild
ungulates for the bulk of daily energy.
            Higher levels of fat intake could conceivably occur with
selective butchering in which fatty tissues were eaten to the exclusion
of lean.    This proposition however, is quite wasteful and over the
long haul, contradicts optimal foraging theory (5).   In all likelihood,
fatty tissues would have always been preferred over lean (3), but the
fatty tissues mainly consumed over the course of the entire year would
have been organs (marrow, brain, perinephral fat, mesenteric fat,
spleen, tongue, gonads, retro-orbital fat, liver, kidney, thymus, heart)
rather than subcutaneous depot fat; simply because subcutaneous fat
depots are negligible for most of the year.    The fatty acid
composition of organs is quite different from that of subcutaneous fat
depots in which saturated fat prevails.   Most organs are quite high in
long chain PUFA of both n3 and n6 varieties; often times they are also
quite high in MUFA; rarely if ever do they contain higher levels of
saturated fat relative to the combined PUFA and MUFA (6).   Further, the
total amount of organ meats, relative to muscle meat in a single animal
is quite small.   Consequently, even with the selective consumption of
organ meats, the total fat energy in the diet would still not approach
western levels because of the diluting influence of high consumption of
lean meat (as predicted by optimal foraging theory) which averages ~2%
by weight or 17% by energy.
        The muscle meat of wild animals is much less saturated than is
that of domesticated animals (3).   The  saturated fat content of 3
domesticated muscle meats (lamb, beef, pork - averaging 4.2% total fat )
has a mean saturated fat content of 42% (3).   In contrast, the
saturated fat content of 5 wild animals (rabbit, buffalo, sambar deer,
kangaroo, wild pig - averaging 1.4% total fat) has a mean saturated fat
content of 32% (3).   It is apparent that both the relative and absolute
amounts of saturated fats in game muscle meat is considerably lower
(particularly when total energy estimates are used rather than per
weight measures).      Pre-agricultural diets were characterized by
extremely high (by modern standards) protein intakes (35-45% total
energy), low carbohydrate intakes (25-35% total energy) and low to
moderate fat intakes (25%-35%).   Saturated fats would have almost
always comprised less than 40% of the total fat intake.  Thus, it would
have been difficult or impossible for pre-agricultural man to consume a
high fat (>40%energy) diet in which saturated fats were predominant.

                                REFERENCES

1.      Eaton SB.  Humans, lipids and evolution. Lipids 1992;27:814-20.
2.      Speth JD.  Energy source, protein metabolism, and
hunter-gatherer subsistence strategies. J Anthropological Archaeology
1983;2:1-31.
3.      Sinclair AJ, O'Dea K.  Fats in human diets through history: is
the western diet out of step.  In: Wood JD, Fisher AV (Eds).  Reducing
Fat in Meat Animals.  Elsevier Applied Science, New York, 1990, 1-47.
4.      Stefansson V.  The Fat of the Land. MacMillan Company, New York,
1960, pp 28-29.
5.      Hawkes K et al.  Why hunters gather: optimal foraging and the
Ache of eastern Paraguay. Am Ethnologist 1982;9:379-98.
6.      Cordain L et al.  The fatty acid composition of muscle, brain,
marrow and adipose tissue in elk: evolutionary implications for human
dietary lipid requirements.  World Rev Nutr Diet (abstract), 1998, in
press.