In my previous post regarding food scarcity and the "thrifty" gene, I
completely messed up my reference numbering in paragraph #3 from cutting
and pasting errors.  The correct version of that post is as follows:


I would like to respond to Jenny's comment:

> Why is it that many scientifically trained people think
hunter-gatherers
> regularly starved to death, allowing natural selection of the 'thrifty
> genotype' (one susceptible to overweight and obesity today)?  Is it
true
> that we often starved - what is the evidence?

        Implicit in JV Neel's original "thrifty gene" hypothesis (1) is
the assumption that pre-agricultural man must have gone through regular,
periodic episodes of starvation that negatively impacted reproductive
potential and hence resulted in the selection of a gene or genes which
would have survival value during the fluctuations between "feast and
famine".   This concept is frequently invoked to explain the high
incidence of diseases of insulin resistance (non-insulin dependent
diabetes mellitus (NIDDM), hypertension, obesity, coronary artery
disease) among recently acculturated populations (2,3).    John Allen
(one of our members - if he is still listening in the ether) has
proposed the existence of a "non-thrifty genotype" (4) which is more
prevalent in  westernized populations in which these putative
adaptations to feast and famine do not occur.
        Although Neel's hypothesis has become "one of the orienting
concepts of nutritional and biomedical anthropology" (4), it is founded
upon an assumption which cannot be corroborated by the available
ethnographic data derived from living hunter gatherer populations nor by
the fossil record.   Indeed, periodic starvation became more frequent
and nutritional status declined when hunter gatherer populations made
the transition to agriculture (5,6).   Diamond has pointed out that
starvation among early agriculturalist was quite common because of the
dependence upon a few staple cereal crops (7).  If one staple food crop
failed, farmers ran a greater risk of starvation than did hunter
gatherers who could utilize a much broader range of wide  plant and
animal foods.   Modern studies of hunter gatherers show that there is a
seasonal fluctuation in body weight, but these studies do not indicate
any evidence of starvation or chronic malnutrition (8,9).   I havent
carefully examined the northern latitude studies, but  Stefanson  has
reported that  starvation did not occur among the Copper Eskimos (10).
        In a review of 51 references examining human populations from
around the earth and from differing chronologies, as they made the
transition from hunter gatherers to farmers, Cohen (11) concluded that
there was an overall decline in both the quality and quantity of life.
Generally, in most parts of the world, whenever cereal based diets were
first adopted as a staple food replacing the rich variety of wild animal
and plant based foods of hunter gatherers, there was a characteristic
reduction in stature (11,12,13,14) an increase in infant mortality
(6,11), a reduction in life span (6,11), an increased incidence of
infectious diseases (6, 7,11,15), an increase in iron deficiency anemia
(6,11,15), an increased incidence of osteomalacia, porotic hyperostosis
and other bone mineral disorders (6,11,12, 15) and an increase in the
number of dental caries and enamel defects (6,11,16).   Clearly, early
farming brought on not a reduced mortality from starvation and
nutritionally related diseases, but to the contrary, an increase.   If
this is the case, then the advent of agriculture would not have reduced
the selection for a thrifty genotype would have actually increased it.
Obviously, population and epidemiological data indicates this is not the
case.  Therefore, the assumption that starvation was the single and only
factor selecting for a putative "thrifty genotype" could not be correct.
Alternatively, my colleague Jenny Brand Miller (17) has suggested that
the high protein intake of pre-agricultural diets would have represented
a more likely environmental pressure responsible for selecting for
multiple genes originally hypothesized by Neel to be "thrifty genes".
It is likely that Neel's concept of "thrifty" is a misinterpretation of
the true function of these multiple genes.   I refer interested readers
to Jenny's mechanistic explanation for this phenomenon (17) & perhaps
she could comment upon this.
        By the way, as a matter of interpretation - there seems to be a
bit of confusion concerning my previous post correlating latitude to
animal based hunted foods.   I indicated that the mean dietary
subsistence percentage for hunted animal foods for world wide
hunter-gatherers  is 26-35%.   This value is indeed correct - it differs
from previous values I have presented in  this forum because those
values (56-65%) represented the combined animal foods derived both from
hunting and fishing.   These data support Jenny's contention that a high
protein diet would have been the norm for our stone age ancestors, and
that this nutritional pressure may have favored the selection of genes
which promoted survival in the face of ultra high protein intakes.
The sudden (in geological terms) switch to the high carbohydrate diet
with the advent of  agriculture would have produced disssonace (or as my
friend Boyd Eaton says, "discordance") between genes that previously
enhanced survival and a novel environmental pressure (low protein, high
carbohydrate diets).

                                Cordially,

                                Loren Cordain, Ph.D.
                                Colorado State University
                                Fort Collins, CO 80523




                                REFERENCES

1.      Neel JV. Diabetes mellitus: a "thrifty" genotype rendered
detrimental by "progress". Am J Hum Genet 1962;14:353-62.
2.      Wendorf M et al.  Excavation of the "Thrifty" genotype. Diabetes
1991;40:161-65.
3.      West KM et al.  Diabetes in american Indians and other native
populations of the new world. Diabetes 1974;23:841-55.
4.      Allen JS et al.  The non-thrifty genotype. Current Anthropology
1996;37:831-42.	
5.      Buikstra JE. The Caribou Eskimo:general and specific disease. Am
J Physical Anthropol 1976;45:351-68.
6.      Cassidy CM.  Nutrition and health in agriculturalists and
hunter-gatherers: A case study of two prehistoric populations.  In:
Nutritional Anthropology: Contemporary approaches to diet and culture.
Jerome NW, Kendal RF, Pelto GH (Eds). pp117-146. Bedford Hills, NY:
Redgrave.
7.      Diamond J.  Agriculture's mixed blessings.  In: The Third
Chimpanzee.  Harper Perennial, NY, 1993, 180-191.
8.      Wilmsen EN.  Seasonal effects of dietary intake on Kalahari San.
Federation Proceedings 1978;37:65-72.
9.      Bronte-Stewart B et al.  S Afr J Lab Clin Med 1960;6:187-.
10.     Stefansson V.  The Fat of the Land. MacMillan, NY, 1960.
11.     Cohen, M.N. (1987).  The significance of long-term changes in
human diet and food economy.  In: Food and Evolution. Toward a Theory of
Human Food Habits.  Temple University Press, Philadelphia, 261-283.
12.     Eaton, S. B. and Nelson, D.A. (1991).  Calcium in evolutionary
perspective. American Journal of Clinical Nutrition, 54, 281s-287s.
13.     Angel, J.L. (1975). Paleoecology, paleodemography and health.
In: Polgar, S. (Ed.), Population, Ecology and Social Evolution. Mouton,
The Hague, 167-190.
14.     Nickens, P.R. (1976). Stature reduction as an adaptive response
to food production in Mesoamerica. Journal of Archaeological Science, 3,
31-41.
15.     Lallo, J.W., Armelagos, G.J. and Mensforth, R.P. (1977). The
role of diet, disease, and physiology in the origin of porotic
hyperostosis. Human Biology, 49, 471-483.
16.     Turner, C.G. (1979). Dental anthropological indications of
agriculture among the Jomon people of central Japan. American Journal of
Physical Anthropology, 51, 619-636.
17.     Brand Miller JC, Colagiuri S.  The carnivore connection: dietary
carbohydrate in the evolution of NIDDM.  Diabetologia 1994;37:1280-86.