What Did Humans Eat Before Fire?

Before humans discovered fire, our ancestors relied on a raw diet consisting of meat, bone marrow, insects, fruits, nuts, seeds, and tubers, which required significantly more chewing, posed higher risks of bacterial and parasitic infections, and demanded a more robust digestive system with larger guts and stronger jaw musculature; this multi-million-year period of raw food consumption was not merely a survival challenge but an essential evolutionary proving ground that shaped human behavioral flexibility, cognitive development, and social cooperation, ultimately enabling the brain expansion that would define our species.