Why? Of course Northern European had different diets (e.g. lard instead of olive oil etc.) but on the Mediterranean cost diets weren't that similar.
> you can enter ketosis every day on a diet of carbohydrates by eating one or two times a day
So being on the brink of starvation all the time? Does not seem sustainable.
> all of this could have applied to most people until relatively recently
Highly unlikely. What makes you think that was the case?
> had almost none of the diseases we have that are all really metabolic dysfunction/diabetes at their root
True. Unless you were rich. Even heard of gout? But yeah probably somewhat accurate for the whole population. But again, not much to do with ketosis.
I mean is there any evidence even today that someone whose diet is primarily (~80%) grain and other plant products with a lot of carbohydrates can enter ketosis even when practicing "intermittent fasting" while consuming ~2000-3000 calories per day (e.g. the estimate for standard Roman soldier daily rations is 3,000-4,000)? Seems impossible...
> its extremely well established science
You saying this doesn't make it true.