How important are visual cues for determining satiation? To find out, 64 participants were served lunch in a “dark” restaurant where they ate in complete darkness. Half the participants unknowingly received considerably larger “super-size” portions which subsequently led them to eat 36% more food. Despite this difference, participants' appetite for dessert and their subjective satiety were largely unaffected by how much they had consumed. Consistent with expectations, participants were also less accurate in estimating their actual consumption quantity than a control group who ate the same meal in the light.