British Shorthair weight gain at 10

A British Shorthair putting on weight despite careful portioning is a frustrating but genuinely common situation — the breed has a naturally slow metabolism, and once they hit their senior years that slows down further. Cats age more gracefully than dogs in many ways, but they do become prone to specific conditions as they get older: kidney disease, hyperthyroidism, dental disease, and arthritis are the big ones worth watching for. Extra weight makes all of those harder to manage. How old is your cat exactly, are you noticing any other changes alongside the weight gain — drinking more, moving less, any change in coat — and what made you start looking into this now?

That pattern — gradual gain over a year despite measured portions, combined with reduced activity — is really typical of a British Shorthair entering senior metabolism territory. The reduced activity both reflects and accelerates the problem because they burn fewer calories while often still eating the same amount. Dry food, even premium dry, is worth looking at here. It tends to be calorie-dense, and cats don't always compensate by drinking enough water, which matters more as they age. What dry food are you currently feeding him, and do you know roughly how many calories you're giving per day?

So at 6.5kg he's already carrying more than the ideal weight for the breed — British Shorthairs should typically sit around 4 to 5.5kg for males. The Indoor Adult formula is decent but it's not formulated for weight management, and 60g of a standard dry food can be more calories than a less active senior needs. The clearest single change I'd recommend is switching to Royal Canin Satiety Weight Management dry food for cats. It's specifically engineered to create a genuine feeling of fullness on fewer calories — higher fibre, lower fat, and it doesn't leave cats pestering for more food the way a simple calorie reduction on normal food tends to. It's widely available on Amazon UK and easy to transition to gradually over two weeks to avoid digestive upset. That said, at 10 and gaining weight despite doing everything right, a vet check to rule out hypothyroidism or early kidney changes is genuinely worth doing — not because anything sounds alarming, but because catching those early makes a real difference.

Royal Canin's feeding guide for Satiety puts a 6.5kg cat needing to lose weight at around 45 to 55g per day — so noticeably less volume than you're giving now, which is partly the point. The formula is denser in satiety fibres so he should feel satisfied on less. On wet food — yes, adding some is actually a good idea for a senior British Shorthair. It increases water intake, supports kidney function, and wet food generally has fewer calories per gram than dry. A practical approach is to give roughly 40g of the Satiety dry plus a small portion of a good quality senior wet food once a day. Royal Canin also do a Satiety wet pouch that pairs well, or any grain-free senior wet food with named meat as the first ingredient works fine. The combination tends to produce better weight results than dry alone.

That's exactly the right combination — the diet change will start working within a few weeks and the vet check gives you a clean baseline for his senior years. Aim for a recheck weight in about six to eight weeks; you're looking for slow loss, around 0.5% of body weight per week at most, so nothing dramatic. British Shorthairs are wonderfully robust cats when they're at a healthy weight, so it's worth the effort now.