My girls eat any where from .75 cups twice a day to more than 2 cups twice a day. This varies by meal too, more if they seem thin or I have been working them hard, less if they seem pudgy or have been sedentary.
My guys get 'cookie time', they have to earn cookies by performing somehow, at least twice a day, and get a large bedtime biscuit, and nibbles of our food, so they have several eating opportunities a day :-) This makes a Labrador happy!