Homo Sapiens Sapiens are omnivore. They'll eat anything they can find or catch.
Cooking helps, as our ancestors found.
+1
We are super adaptable.
Our main system for producing energy (ATP) for our cells is the aerobic system; it's a pretty complicated pathway but our bodies can use carbs, fat & protein for this using The Krebs Cycle. At higher power outputs the higher oxygen demand for burning fat makes glucose/glycogen a preferable choice where power matters. (There are other means of producing energy Phospo Creatine system, Cori Cycle etc).
Once your source is real whole food possible to construct a healthy diet with all types of macros.
On ketosis (which I've tried but don't practice) not sure how one can say definitely that it's unhealthy; how could we have evolved without it? During periods of starvation, winter with low plant supply etc where would our brain get the necessary 600 cals a day or so for the 1kg organ on top of our shoulders that will only run on glucose or glucose/ketones. Without the adaption to enter ketosis (or some other back up system) how could we have survived times of scarcity?
While a love of nature/animals is an admirable quality, using it as a basis for asserting what is the correct way for all people to eat all of the time leaves one a little vulnerable to an accusation of bias.