Not taking a side here one way or another....

>The use of fire sets humans apart. 

Can't argue with that - for good or for bad.

>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.

Kinda broaching another subject here, but this has always been my beef with the "Lights Out" crowd. I'm really doubtful that "modern" cavemen regularly went to bed at sundown and got up at sunrise (well, maybe the sunrise part :) I'm pretty sure once fire was tamed they would have spent plenty of time dreamily looking into the fire at night and talking about the "lights in the sky", etc. Just as many of us "moderns" do.

> Wrangham disagrees, arguing that humans cannot easily digest raw meat

I'm not sure if "digest" is the appropriate term here. Perhaps they are trying to say assimilate? (Of which I cannot judge one way or another)

> Followers of a strict raw-food diet invariably lose weight. 

Is this a truism? If so, it would go a long way toward explaining many facets of obesity.