The following I found in "Cultural Anthropology" by Roger M Keesing,
wich in turn has cited it from Divale and Harris, American
Anthropologist 1979:532-533 :

"Any sudden shift from high-protein, low-calorie diets to low-protein,
high-calorie diets, should produse a spurt of population growth,
followed by an increase in female infanticide and the intensification of
warfare. The Yanomama of Amazonia may be th classic case. Expasion of
their investment in banana and plantain gardens probably provided the
starchy calorie supply...a population explosion among the central
villages. This expansion may have adversely affected the fragile
animal-protein ecology typical of interriverine Amazonian habitats.
Female infanticide produced junior-age sex ratios of 148:100 for 11
Yanomama villages in the intensive warfare zone, and an intense male
supremacist-warfare complex developed. But in 12 Ynomama villages that
were peripherically loctated, junior-age sex ratios were only 118:100
and warfare less intense ... . Recently fissioned groups fought each
other for possession of ... garden sites, as well as possession of the
proportionately decreasing number of woman and protein resources."

To me this tells something about the importance of animal food.
Also, when evaluating the percentage of animal food of recent h/g
people we have to consider that some of those who do not eat so much
animal food should have eaten more if they were able to get it.

- Hans