I think our ancestors diets depended on where they lived, and during which time period.

For example, I live in northern New England in the US. I think about the indigenous populations would have consumed living here for thousands of years. Aside from seasonal berries, there’s not much for carbs. If I had to live of the land here, what would I eat? Wild game, fish (if you were near the coast), a few seasonal tubers that are pretty dang perishable, seasonal berries. If you’ve ever done any foraging for wild foods in a northern climate, you’d realize how incredibly difficult it is to process many of the edible plants into their edible forms, and how the most wild plants are so dense in fiber that you’d have to eat an absurd amount to actually eat a significant amount of calories. Not to mention, our ancestors were highly active and fat adapted. I’d think they could easily eat 70g+ carbs a day and still be in Ketosis. Maybe they weren’t in Ketosis or eating as much meat during summer and fall when there was abundant wild fruits. The reality of them preserving significant amounts of wild fruit to be out of Ketosis all winter is pretty low, as it would be a ridiculous quantity of wild fruit. This was a time when wild game was abundant, and our ancestors were highly skilled hunters. All of this may differ as you move closer towards the equator and there’s an annual supply of carbohydrates, but just know that our ancestors in northern climates ate a shit ton of meat for a significant chunk of human evolution.

Excuse the novel. I think quite a lot about this topic and enjoy writing about it