Many children eat very little but manages to survive anyway. Do not nag him but let his own apetite decide. See to it that there is always his favourite food there in case he gets hungry. Notice his preferences and serve that in his room. Children can be very conservative in their choice of food. Many children find it easier to eat alone sitting in front of the TV. They eat so slow and little, that the family is provoked by watching. It is important for you to not loose you temper in front of him so that his eating habits become a powerstruggle between you. It is sometimes easier for the child to drink a glass of milk after the food rather than eating a full meal.