No set answer.
Different children have different needs.
Does he eat 3 meals, 6 meals, 9 snacks?
Some kids that age snack non-stop.
More important is the overall consumption.
I would say if he consumes more than 1 and half cups of healthy food a day and takes his vitamins and drinks 16 plus ounces of milk he is okay.
at 9:14 AM on Sep. 30, 2010