There seems to be an acceptance that we ate fruits and vegetable matter.
Here are a few notes that I made on the book with page references. Some notes are from reading the reference material or independent research.
Page 30 - Millenium Man of Kenya shows that bipedalism was in use 6 million years ago by an agile climber who walked on the ground and ate fruit and vegetable matter.
"At the University of Toronto, David Popovich has been studying the micro-nutrient content of the wild vegetation consumed by gorillas. He has found that much of the energy and nutrient value that gorillas are able to derive from such a diet comes from colonic
fermentation. Their studies on human subjects have shown that humans may also be able to rely on colonic
fermentation. Thus, a diet consisting of substantial quantities of fruits, vegetables and nuts - no pasta or starches - will provide adequate protein, B-12 and amino acids (the building blocks of protein). Gorillas and chimpanzees have little trouble digesting cellulose thanks to the presence of the ciliate Troglodytella in their intestines. However, chimps and gorillas in captivity begin to lose their Troglodytella when they are fed cooked food. Thus, it is reasonable to assume that humans lost their intestinal cilia when they started cooking with fire."
Page 44 - Bacteria in human colons proved quite efficient at fermenting the fibre of fruit and vegetables. The microbial populations fermented some three-quarters of the cell wall material, and about 90% of the volatile fatty acids that resulted were delivered to the blood stream.
Page 45 - our gut microflora are very sensitive to different types of dietary fibre. We are very efficient at processing vegetable fibre from dicotyledenous sources (flowereing plants like fig trees, carrots and lettuces) but are less so from monocotyledens (grasses and cereals)
Page 48 - The Sugar
in wild fruit tends to be rich in glucose and fructose compared to cultivated fruit that has been bred for its sweeter tasting sucrose content.