A puppy's nutritional needs change based on his age, but in general, he requires more nutrients than an adult because he is growing rapidly. He is ready to eat solid foods after four weeks and should be fully weaned by six weeks. Afterward, he should eat a high-protein diet.
A puppy's exact nutritional requirements depend on his breed, size and age, but he should be fed a brand with 25 to 30 percent of the calories coming from protein. He generally needs to eat twice as much as an adult would based on size, especially during the first five months. At 6 months, it may be appropriate to scale him down from three meals per day to two.
A small-breed puppy can usually be trusted to eat only when hungry. However, a large-breed puppy likely needs portion control and a more-specialized diet. Too much food can promote rapid growth, so large-breed puppy foods are designed to control growth, provide nutritional supplements and to prevent problems. Overfeeding a dog, even if he is an adult, can contribute to future problems and increase the likelihood of hip dysplasia.
A puppy's treats should be no more than 5 percent of his calories per day. He should not be fed table scraps, and treats should be appropriately sized.