Are we meat eaters or vegetarians? Part II
Meat eating made us human. The anthropological evidence strongly supports the idea that the addition of increasingly larger amounts of meat in the diet of our predecessors was essential in the evolution of the large human brain. Our large brains came at the metabolic expense of our guts, which shrank as our brains grew.
In April 1995 an article appeared in the journal Current Anthropology that was an intellectual tour de force and, in my view, an example of a perfect theoretical paper. “The Expensive-Tissue Hypothesis” (ETH) by Leslie Aiello and Peter Wheeler demonstrated by a brilliant thought experiment that our species didn’t evolve to eat meat but evolved because it ate meat.
The ETH is an example of the kind of scientific detective work that I love. In fact, this paper is one of my all time favorites. (An amazing bit of trivia about this paper is that it almost didn’t get published. I had the opportunity to talk with Leslie Aiello at a meeting a few months ago, and she told me that the journal was reluctant to publish the paper because they thought it too technical for their readers. I suspect they also found it too controversial. Now I’m sure they’re glad they published because I would imagine it is the most cited of all the papers ever published in Current Anthropology.) The authors methodically lay the scientific foundation for their experiment, then, like Sherlock Holmes, progress step by step, accumulating little pieces of data until they reach the ineluctable conclusion that meat eating made us human. I would like to walk us all through their thought processes as laid out in their brilliant paper.
