The latest clue as to why our modern diet may be making us sick comes

 The latest clue as to why our modern diet may be making us sick comes

 from Harvard primatologist Richard Wrangham, who argues that the biggest revolution in the human diet came not when we started to eat meat but when we learned to cook. Our human ancestors who began cooking sometime between 1.8 million and 400,000 years ago probably had more children who

 thrived, Wrangham says. Pounding and heating food “predigests” it, so our guts spend less energy breaking it down, absorb more than if the food were raw, and thus extract more fuel for our brains. “Cooking produces soft, energy-rich foods,” says Wrangham. Today we can’t survive on raw, unprocessed food alone, he says. We have evolved to depend upon cooked food.

To test his ideas, Wrangham and his students fed raw and cooked food to rats and mice. When I visited Wrangham’s lab at Harvard, his then graduate student, Rachel Carmody, opened the door of a small refrigerator to show me plastic bags filled with meat and sweet potatoes, some raw and some cooked. Mice raised on cooked foods gained 15 to 40 percent more weight than mice raised only on raw food.