Marilyn Harris:
> I am beginning to wonder about too much fats in our diets. 
> First, from reading about the non-protective associations 
> involving fats and cancer and after just reading about how 
> Nathan Pritikin's arteries were found to be absolutely clean 
> like a teenager's:
> 
>
http://www.pritikin.com/eperspective/specialissues/pritikinatkins/index.htm
> ... I just wonder whether our diets should change as we grow older to
include way more vegetables and far less
> meats/fats? Or at least the right type's of fats? Maybe more monosaturated
or those with high levels of omega 3s?

Hi Marilyn,

I don't know. I had read about Pritikin and was pretty impressed by his
autopsy as well, and not as impressed by the fact that no autopsy was done
on Atkins and he had heart disease, yet his supporters claim it was not diet
related. However, there is no scientific theory underlying the Pritikin diet
and I haven't seen any studies that demonstrated its efficacy for a sample
group.

> Should we not base the creation of an optimum diet for humans on clues
derived from our physiology and from comparative
> studies of similar physiques of other animals and not necessarily from our
hunting abilities? 

I wouldn't start with any of those, though they are all clues to consider. I
would start with trying to figure out what our species, homo sapiens,
generally ate when it was in its natural environment in the wild and
semi-wild (its "primitive" state). Based on evolutionary theory, the key
starting point to look at would seem to be the period during which our
species developed, though earlier periods would provide some relevant
information as well. A key demarcation point would be when humans started to
consume a diet much more of their own creation (pastoral and agrarian),
rather than what they found in the wild. Another key demarcation point would
be when they used modern technology to further alter their foods (industrial
processing, chemical additives, and invented food products). These points
would signal when our diet started going downhill and accelerated its
decline, I think.

> Does meat-eating increase life-span or brain-size? 

There is a hypothesis that it contributed to the evolution of larger hominid
brains, but it is hotly debated. Whether meat added to life-span, I don't
know. Meat does seem to improve fertility and increase co-operation in
mostly plant-eating primates like chimps, based on the work of Goodall,
Leakey and others. Leakey thinks that the cooperation that hunting and
sharing of meat required and encouraged was more important in the
development of humans than the