Richard Wrangham figures our hominin ancestors tamed fire and started cooking with it 1.8 million years ago. Other authorities date our mastery of fire from 12,000 to 400,000 years ago.
From the New York Times:
“When early humans discovered how to build fires, life became much easier in many regards. They huddled around fire for warmth, light and protection. They used it to cook, which afforded them more calories than eating raw foods that were hard to chew and digest. They could socialize into the night, which possibly gave rise to storytelling and other cultural traditions.
But there were downsides, too. Occasionally, the smoke burned their eyes and seared their lungs. Their food was likely coated with char, which might have increased their risk for certain cancers. With everyone congregated in one place, diseases could have been transmitted more easily.”
Source: Smoke, Fire and Human Evolution – The New York Times