Share 'Calorie needs'

How can we estimate the calorie needs of a nearly non-ambulant child who is 16 Years old.I have been trying to find information about the optimum amount of calories to feed my son who is suffering from DMD,but there isn't much information.Are there no trials conducted to estimate the nutritional needs of our children.My son takes prednisone,so it is hard to maintain his weight and he is very shor…