Without cooking, an average person would have to eat around five kilos of raw food to get enough calories to survive.
The daily mountain of fruit and vegetables would mean a six-hour chewing marathon.
It is already accepted that the introduction of meat into our ancestors' diet caused their brains to grow and their intelligence to increase.
Meat - a more concentrated form of energy - not only meant bigger brains for our ancestors, but also an end to the need to devote nearly all their time to foraging to maintain energy levels.
(Hat tip: Bayou Renaissance Man)