Paleo diet: Dr. Loren Cordain's rebuttal to the National Academy of Sciences.

Dr. Loren Cordain is considered by many to be the founder of the Pal(a)eolithic diet.

From http://thepaleodiet.com/dr-loren-cordain/

He wrote this:- Rebuttal to the Proceedings of the National Academy of Sciences June 2013 Papers

"In summary, recent comprehensive analyses (1-3) of δ13C values in the enamel of African hominins from 4.1 to 1.5 MYA support the conclusion that plants of C4 origin were ultimately responsible for this isotopic signature. Nevertheless, when the isotopic data is triangulated from archaeological, physiological and nutrition evidence, it is apparent that the C4 signature in ancestral African hominin enamel almost certainly is resultant from increased consumption of animals that consumed C4 plants."

EDIT: Hat-tip to Robb Wolf.