Here is a letter I wrote to the Dominion Post on 1 September 2019 that wasn’t published.
David Ruddlesden (Thurs 29 Aug) seems to think we are designed to be primarily carnivores.
Carnivores have long, sharp, canine teeth, jaws that open wide enough to swallow a large catch and a very large stomach to contain it. Stomach pH is 1, the acidity of battery acid. They have a short gut, claws to hold prey, bent knee joints ready to pounce, they are fast on their feet and have eyes designed to detect motion at night.
Herbivores have small canine teeth, teeth and jaws are designed to grind rather than tear, a small mouth and relatively small stomach. Its pH is 4. Their salivary glands produce amylase, an enzyme evolved to start digesting starch. They have a long digestive tract, and food spends a long time in the large intestine to ferment fibre. Their eyes are designed to focus on and be attracted by ripe fruit. They don’t have claws.
Paleolithic humans from all continents were more gatherers than hunters. Their women provided the staple diet of roots, leaves, berries and fruits while their men occasionally caught animal or fish prey which didn’t last long before it went rotten.