The easiest way to determine your cat’s ideal weight, and if it needs to lose or gain weight, is by asking your veterinarian during your annual wellness appointment! This is where we (your friendly neighborhood vet) can discuss body condition scoring, the amount of calories required for their stage of life, any change in food, and a weight loss plan if indicated.
We judge a cat’s weight based on a body condition score (BCS) out of 9, where a 5 on the scale is ideal, a 1 is severe emaciation, and a 9 is severe obesity. This scale focuses on palpable fat over the ribs and spine, as well as if there is visually a “waist” from above, and how prominent the abdominal fat pad is (how low does the belly swing). In general most adult cats sit around 9-11 lbs on the scale, but there is some variation particularly in pure-bred cats (Maine Coons can be healthy upward of 15 lbs!).
To determine the amount of calories your cat should be eating, we calculate their resting energy requirement (RER) and their maintenance energy requirement (MER). The RER is based on their weight, and from there, their MER is calculated taking into consideration if they need to gain or lose weight, how old they are, and what their activity level is like. For instance, for a 10 lb neutered adult cat that lives inside and has a BCS of 5/9, they will need roughly 260 kcal/ day to maintain that perfect weight. Now 260 kcal may not sound like a lot, but to a 10 lb cat, it is the perfect amount!
There are a lot of handy resources on Purina’s website for help determining your cat’s BCS and MER. As always though, we are here to help! Feel free to reach out for an appointment to discuss your cat’s nutritional needs, or bring it up at your next wellness appointment.