Is he eating raw veggies now and wouldn't touch them before? If this is the case you can steam or cook them just a little first. It can also be a very good sign of a food intolerence. Have him start keeping track of what he eats and what seems to upset his tummy. For me it was dairy. Once I cut out the cheese and heavy cream the problem cleared and I lose weight much better. I made the mistake of having pizza toppings last night and was miserable with gas and a small amount of diareah all night last night.