Why humans started cooking

I find the argument that cooked food provides the human eating it more energy very plausible, and am surprised that it is controversial. (Is it really?)

This article appeared some time ago on HN, suggesting that the advent of cooking, and the higher amount of energy we could derive from cooked foods, allowed us to evolve a reduced gastrointestinal system and our big powerful brains:

http://news.bbc.co.uk/2/hi/8543906.stm