Have you seen the following article from "New Scientist"?

How fire made us human, by Saswato R. Das

"THE inhabitants of the Admiralty Islands say that a divine serpent
once asked some children to cook a fish. The children dried it in the
sun and ate it raw. Seeing this, the serpent gave them fire and taught
them to cook.

So it is with every culture: the way that humans acquired fire is
enshrined in legend, usually involving either a heroic benefactor or a
trickster. In Greek myth, Prometheus stole fire from the gods and was
punished for it; according to the Apache, it was a cunning fox who
captured it for us. Once acquired, fire became sacred. In ancient
Rome, it was guarded in the temple of Vesta, goddess of the hearth, by
the Vestal Virgins. In India's Hindu temples, Agnihotri (literally
"fire-guarder") Brahmans are still keepers of the sacred flame.

Legends aside, no other animal controls fire. Most fear it. The use of
fire sets humans apart. But what difference has it made?

Anthropologist Frances Burton suggests that taming fire led to the
evolution of modern humans. Millions of years ago, our ape-like
ancestors may have overcome their fear of fire to pick at found
delicacies - maybe an animal accidentally cooked in a forest fire.
Over time, they learned how to keep a flame going by feeding it twigs,
how to use fire to thwart predators and how to harness it for heat and
light. This familiarity with fire, Burton argues, changed the hormonal
cycles that depend on light and darkness: light from nightly bonfires
may have caused a change in the nocturnal flow of melatonin. Over
time, this changed the rates and patterns of our ancestors' growth,
and the regulation and activation of genes, leading ultimately to us.

Primatologist Richard Wrangham, who has been observing chimpanzees in
Africa for 40 years, believes it is cooking itself that makes us
human. The pre-human species Homo erectus, which evolved in the
African savannah roughly 1.8 million years ago, was in many ways
similar to us: it had an upright body, long legs, large skull and
small gut. As Wrangham puts it, H. erectus could have worn our
clothes, unlike the apes that came before it. Scientists usually
explain this change in body shape by a change in diet, explaining that
learning how to make tools enabled our ancestors to catch more
animals. This allowed H. erectus to eat more meat, and because meat
has more calories than plants in a given volume, a smaller gut
sufficed.

Wrangham disagrees, arguing that humans cannot easily digest raw meat
and so our smaller gut must have evolved as a result of cooking. Just
look at today's raw-food movement, he says: followers of a strict
raw-food diet invariably lose weight, even though they do not have to
expend the energy that would be required to hunt and gather their
food. Our ancestors, who had no such choice, would have starved if
they had relied on raw food alone.

Followers of a strict raw-food diet invariably lose weight. Our
ancestors would have starved
Cooking changes the game dramatically. For one thing, it helps break
food down so that we expend less energy chewing and digesting it.
Cooking also allows us to absorb more energy from food by denaturing
protein and breaking down indigestible carbohydrates such as cellulose
into more digestible pieces.

Wrangham builds a compelling case, although archaeological proof of
his theory has yet to be found. There is evidence, however, that H.
erectus may have conquered fire: the oldest known hearths date from
about 800,000 years ago, discovered in Israel on the banks of an
ancient lake in the Jordan valley, about 600,000 years before modern
Homo sapiens emerged.
These fascinating books show how the biological evolution of human
beings may not have been a matter of biology alone, and why, as
Wrangham writes, "we humans are the cooking apes, the creatures of the
flame".

Saswato R. Das is a science and technology writer in New York
http://www.newscientist.com/article/mg20227112.500-how-fire-made-us-human.html?DCMP=OTC-rss&nsref=online-news