How did her studies on the digestion of fiber by chimpanzees support this idea?

Question

Dr. Milton argues that despite adaptions favoring high quality(low fiber) food, human ancestors ate much more fiber than we do today.

Answer 1

Chimpanzees perform coprohagia i.e eating feces.
This is because they too cannot digest completely food fibers.
Chimps evolved separately from species HOMO at about 7 million years before.
Chimps have remained more or less the same, but we have changed drastically.
Thus Dr.Milton's argument is right.
Human ancestors ate much more fiber than we do today