Back in the day our keto hunter primal ancestors, likely the men, we’re hunting animals, eating fattest parts tossing the rest to the dogs (or women and children), or having a poor hunt and running on the ketones. Their bodies were evolving to eat this way and to thrive this way.
The other half of the population, the women, were likely eating meat brought back that was less fatty. In every society I have ever heard of , the women were burdened with the children, or pregnant. As they were not as likely to be hunting with children, they were probably gathering what edible plants and roots they could. This was certainly partially true of the American Indians. So their bodies were evolving and thriving on less fatty meats, edible plants and roots, or running on ketones.
I wonder if this might account for the difference in how men and women’s bodies store and use energy. Was just thinking about this a bit.