Just caught the second episode (Guts) of this series on BBC iplayer.
There was some really interesting ideas. I've always been told that it was the introduction of meat to the diet of our distant ancestors which led to increasingly larger brains, due to the high calorie requirement. It maybe that the cooking of plant foods/tubers alone allowed us to gain enough calories to power larger brains because of the reduced chewing time and quicker digestion. Meat was always a supplementary food and unreliable at that, so it would make sense if meat consumption wasn't the primary force driving increased brain sizes.
A possible counter to the "we wouldn't have evolved to be what we are without meat" argument.
It also (indirectly) raises questions on the suitability of the raw food diet for humans, as the cooking of foods seems to have dramatically driven our evolution (e.g. jaw/teeth size - and now brain size!). Obviously our ancestors would have eaten a lot more raw food than the average person nowadays, but it's looking like cooked plant foods may have made up the best part of our diet. This was before we had started farming and taming animals, so the lack of live plant enzymes can't have had a significant effect on our survival chances, otherwise we wouldn't be here (maybe, who knows).
