Cat constipation & dry food: switching to wet

A 9-year-old on dry food their whole life with constipation issues — that combination is really common, and honestly the dry food is almost certainly a big part of the problem. Cats are obligate carnivores with very specific nutritional needs, and many commercial dry foods don't fully meet them. More critically, dry food contributes to chronic low-level dehydration, which directly affects gut motility and kidney function — both serious concerns in a senior cat. Constipation is often one of the first visible signs that the body isn't getting enough moisture. Can you tell me a bit more: is this occasional constipation or a persistent issue, has your vet weighed in on it at all, and has your cat ever shown any interest in wet food or do they flatly refuse it?

Six months of constipation is a real quality-of-life issue and your vet is right that water intake is the lever to pull — but just adding water to dry food rarely works well enough because the kibble expands and cats often reject the texture. The more effective move is transitioning to wet food, which delivers moisture as part of the food itself rather than relying on your cat to drink more. The challenge you'll face is that lifelong dry-food cats sometimes stage a full hunger strike when wet food appears. The key is going very slowly — start by offering a tiny amount of wet food alongside his usual dry, let him sniff and investigate without pressure, and gradually shift the ratio over two to four weeks. Has he ever shown any interest in strong-smelling foods, like fish or meat-based treats? That tells me something about which wet food is most likely to get him over the line.

Good — fish preference is really useful information, and the fact that he's otherwise healthy means you're dealing with a manageable problem rather than chasing multiple issues at once. For a senior cat with chronic constipation transitioning off lifelong dry food, I'd recommend Royal Canin Digestive Care wet food in the loaf format. It's specifically formulated to support gut motility, has a high moisture content, and the smooth loaf texture tends to be more accepted by cats who've never encountered pâté or chunks. The fish varieties give you something in his flavour wheelhouse. It's not cheap, but for a cat with an active digestive issue it's worth using a targeted food rather than a general senior wet food, at least while you're getting the constipation under control. Once he's reliably eating wet food and the constipation has resolved, you'd have more flexibility on brand.

It's a fair question and worth taking seriously. Chronic dehydration from dry food does increase the risk of kidney disease in cats, and at nine years old he's entering the age range where it becomes more prevalent. I wouldn't panic — many cats who've eaten dry food their whole lives have perfectly functional kidneys — but I'd suggest asking your vet to run a basic blood panel including kidney values at his next check-up if they haven't recently. Early kidney disease is very manageable if caught early, and getting him onto wet food now is genuinely one of the best things you can do to slow any progression. The move you're already making is the right one.

That's exactly the right plan. Go slowly with the transition — don't remove the dry food abruptly or he'll dig his heels in. A few weeks of patience now will pay off significantly for his gut and kidney health long term. Good luck with him.