When and how often you feel hungry is a well-documented to be a conditioned response based on eating patterns, it isn't intrinsic unless you go quite a long time without eating. Human eating patterns have considerable flexibility. A person with a normal metabolism can habitually eat one meal a day without being any more hungry than someone that eats three meals a day with snacking in between.

Unless they are on a particularly aggressive program of calorie reduction, eating less than they are eating now is not asking them to be perpetually hungry.