It may not seem as though your cat is doing much when he is lounging near a sunny window for hours on end, but he's burning energy - and a lot of it - all day. In fact, your lap cat needs more energy-producing nutrients, like protein, than most dogs do in order to stay healthy and active.
As your kitten reaches adulthood, his nutritional needs change. He needs less protein and fat and fewer calories. You can switch your cat to an adult food when he's one year old. When you switch to a new food, do it gradually. Over a two-week period mix in more and more of the new food as you decrease the amount of his original food.
The short answer: Pick a premium food formulated for your adult or older cat. Most premium pet food manufacturers invest considerable time and money researching the best formula for cats and performing feeding trials. These trials test cats who eat the food to make sure they're getting the balanced nutrition they need to keep them healthy. And while different brands of premium products may include a different mix of nutrients, all contain high-quality ingredients, which is one of the most important factors in choosing an adult cat's food.
Remember, when you're choosing a pet food, you generally get what you pay for. More expensive products are usually made from higher-quality ingredients, which means your cat can digest the food more easily and retain more nutritional value from each bite. And because your pet eats less when it's a high-quality product, you'll have less work when you go to clean the litter box.