Assuming you are talking about a healthy, average-sized cat, they should be eating around 24 to 34 calories per pound every day. So, an 8-pound cat would need around 192 to 272 calories each day. However, this amount can vary based on things like the cat's age, activity level, and if they are spayed or neutered. For example, a sedentary senior cat may only need 20 calories per pound while a very active kitten could need up to 40 calories per pound.