My 11 year old neutered boy has been on Royal Canin Satiety for the last 18 months or so as he need to lose 2kg. He's now done this and I have upped his food to the maintenance level. However he is nearly ALWAYS crying for food. I feed him morning and evening, but an hour after his meals he wants more. He is up to date with his worming. Should I change his food to something more suited to a hungry, 11 year old??