There's been a lot of discussion here about fats and the thoughts range
from Mary Enig on the one hand to those who still shun saturated fat and
can't get used to the idea of getting upwards of 50% of their calories
from fat.  My brain is pushing me in Enig's direction, but cultural
conditioning is pulling me back from a commitment.

What I'd really like to know is what the fat profile and content was of
the animals consumed by our paleolithic ancestors in the late
Pleistocene.  Seems to me there are four classes of beef (and I'd like to
confine the discussion to beef, so we are comparing like with like):

(1)  Feedlot fed cattle (applies to farmed fish, too, for that matter):
characterized by antibiotics, added growth hormones, unnatural foods and
minimal exercise.

(2) Grass-fed beef - but not organic.  They have their feed supplemented,
are kept well with antibiotics, their pastures are artificially fertilized
and they, too, have minimal exercise compared with their Pleistocene
ancestors.

(3) Organic and Bio-dynamic meat.  The cattle have food inputs that are
close enough to Pleistocene, except in three repects (i) minimal exercise
(ii) generally have adequate and reliable food and water - no serious
stress (iii) castration of bulls.

(4) near-Pleistocene quality.  Some Australian beef falls into this
category, at least in non-drought years.  The cattle roam free, unbothered
by humans for a year, they exercise naturally, are exposed to natural
stresses, but are mustered annually for culling, calf-branding, vet
inspection etc.

I would really like to know the ratio of SFA : MUFA : PUFA in each of
these four classes, also the profiles of EFAs within those three groups,
especially, of course the Omega-6 and Omega-3s.

Loren Cordain in his 2002 paper <Tissue fatty acid composition in wild
ruminants> adopted a different typology:

(1)  North American elk, mule deer and antelope (but were they wild? from
a farm? from a zoo?)

(2)  African ruminants - cape buffalo and eland (ditto)

(3)  Steers grass-fed in N America - note that steers are castrated
bulls.  I understand that castration is undertaken to render the animals
more docile and to increase their ability to put on weight.  It is an
unnatural process and is significant enough, in my view, to render
comparison with uncastrated wild ruminants vulnerable to the effects of
this large uncontrolled variable

(4)  Steers grain-fed in N America (ditto)

His conclusions were that, broadly speaking, the first three of his
classes had similar fatty acid profiles while the fourth stood out as
significantly different.  However, I find his conclusions do not go as far
as I would like to be able to go to identify a Pleistocene benchmark for
beef.  Once we have a Pleistocene benchmark we can look at (a) the
significant characteristics of the fatty acid profile of the benchmark and
(b) the compromises and concessions we would accept for both day-to-day
nutrition of healthy people and the special needs of disease prevention
(the focus of Cordain's article).

Do any list subscribers have further information which helps establish a
Pleistocene benchmark?

Keith