Ancestors of the original man. And if you don't know who the original man is then I can't help you. Most of the world's remaining hunter-gatherers live in Africa and are still practicing this lifestyle to this day. San Bushmen typically track animals that they are hunting for several days and lots of miles. Then when they make the kill they eat the whole animal in one day (because there are obviously no refrigerators in the desert). Then they rest and start the cycle up again.
Our ancestors were not eating everyday. They were definitely not eating 3 meals a day. They would eat every few days after they made a big kill. The rest of the time was spent tracking animals which expended lots of energy. This is why I'm telling ya'll you can fast and still get intense workouts in. Our bodies evolved to work even when we haven't had food for several days because it was necessary to survival.