Our chickens cost nothing to keep and they provide meat when they stop laying, three lambs bought in spring and killed in November keep us in good quality meat and save me work on grass cutting and hedge trimming. Try living on a diet that is natural to the northern hemisphere, no potatoes, tomatoes, oranges etc. Our long distant ancestors started eating meat and their brain size increased, this also gave them time to develop culturally, if we had continued to spend every waking minute searching for nuts and berries, we would still be in the trees.
I don't know what you were eating but most vegetarians stuggle not to eat too many carbs, oils and sugars. Winter's easy, grains, pulses and nuts all last and don't need feeding like animals do.
Poor hunter uhuh....not convinced. The majority of food procured by hunter gatherers isn't meat. A man with no wife goes hungry because she and her children forage most of the grub.
cheers,
Toddy