Early humans ate meat, plants, insects, fruits, flowers and bark. According to LiveScience, eating meat caused physiological changes which made today's human possible. Nutrients in meat were found to allow the growth of the modern human's bigger brains.
Before the 2014 discovery of ancient human waste showing the diet of Neanderthals, many scientists thought that these early humans ate a diet consisting mainly of meat. The discovery that Neanderthal was omnivorous changed the way scientists considered human evolution. Research detailed on the LiveScience website concluded that the skull of an ancient infant showed signs of B12 vitamin deficiency. A nutrient derived only from animal sources, the B12 deficiency proved that these early humans needed meat for proper brain function.
Reports cited on Nature.com found that early humans developed specialized tools to remove the meat and marrow from animal bones. The discovery led researchers to determine that early humans regularly consumed meat. Although scientists did not pinpoint exactly when humans began eating meat, fossil evidence pointed to an earlier date than first suspected. Chimpanzees also regularly consumed meat, however it was a small part of their diet. The reports also concluded that early humans ate nuts, grains and other hard foods in addition to meat. Tooth evidence revealed molars that chewed hard food.