[VLM]

"Are you primarily speaking to our consumption of processed foods?"

Primarily, although massive grain consumption is evolutionarily very recent, so that counts too.

"Also, what was the diet of our ancestors, and how was this information about our ancestral diet ascertained?"

Talk to the archeologists. However it doesn't require much research to determine very few people ate twinkies or drank coffee a thousand years ago. I would not recommend talking to public relations firms, or people collecting a paycheck from the food industry in general.