Well, a puppy is usually considered an adult dog when it is 1-2 years old. I think it may be about time for adult food. Your dog will become fat if you don't change to a healthier puppy food or to an adult food. He mat not look fat now, but he will. Be careful about changing dog foods, dogs can get sick when you change its food. If you keep him on the puppy food, change it when he is about 11 months old. I have been keeping Lady on Pedigree Dog Food since she was 11 months old. Before that I gave her Pedigree Puppy Food. By the way, about the exercise thing, you can have your dog get more exercise by training him or having a trainer come and teach him how to play fetch. You can also teach him many other outdoor games that will keep him active. With healthy food and lots of exersise, your puppy will stay in great shape!