Depends on whether you think our bodies evolved to handle a Paleolithic or Neolithic diet.
People (in most of the world, anyway) had no consistent access to long-chain carbs before agriculture.
The question is therefore one of how quickly we evolved physically after they became available.
A pre-agriculture diet would be much heavier on protein. Most types of carbs would be available only intermittently, not as a regular part of the diet.
Not necessarily. Our methods of hunting involved chasing down beasts for hours at a time. You’re looking possibly a whole village chowing down on a single deer.
The evidence is that, from what I’ve read is that we choose from a wider range of foods than even good diets consist of today. Amongst the foods back then would be called weeds today, like Dandelion stalks.
But, if you want to experiment, you could always cut back or increase your intake of proteins and see if that works for you.