A mission to Mars should have an all-female crew, says Kate Green, who participated in a simulated expedition. Over 5 weeks, the female crew members expended less than half the calories of the men and at mealtimes, the women ate smaller portions. Less food would mean a lighter spacecraft payload and reduced fuel.
OK. Since this is already going to be a storm of epic proportions in this thread I'll throw a log onto the fire:
Why go with women if weight and consumption is the primary staffing concern?
Why not train an all dwarf/midget crew? Maybe a few horse jockeys...