Pet obesity has quietly become one of the most common welfare issues facing UK pets, and it’s often harder to spot in your own animal than in someone else’s — a gradual weight gain over months or years can start to look normal simply because you see your pet every day.
How widespread the problem is
According to PDSA, the veterinary charity that publishes annual welfare data on UK pets, vets estimate that nearly half of dogs in the UK are overweight. Cats aren’t far behind: PDSA guidance states that over a third of cats in the UK are overweight, putting them at increased risk of health problems including diabetes, cystitis and arthritis. Rabbits are affected too, with around a third of pet rabbits estimated to be overweight, according to PDSA data.
Why it happens gradually, not suddenly
Pet obesity rarely results from one dramatic change — it tends to build up through small, repeated choices: slightly oversized portions, regular treats and table scraps, reduced exercise as pets age or owners’ schedules get busier, and free-feeding arrangements where food is available throughout the day rather than at set portions. Because the change is gradual, many owners don’t notice their pet’s weight creeping up until a vet flags it at a routine check-up.
Why it matters beyond appearance
Extra weight isn’t just a cosmetic issue. PDSA guidance links obesity in cats to increased risk of diabetes, cystitis and arthritis, while in dogs, excess weight puts additional strain on joints, the heart and other organs, and can shorten life expectancy. The extra weight also makes existing health conditions harder to manage and can complicate anaesthesia or surgery if needed later in life.
How vets assess a healthy weight
Rather than relying purely on scale weight (which varies hugely by breed and size), vets typically use body condition scoring — feeling for a pet’s ribs, waist and general shape — to judge whether they’re a healthy weight. This is something a vet or vet nurse can show you how to do at home between check-ups, since visual and hands-on assessment often catches gradual changes that are easy to miss day to day.
Managing weight loss safely
PDSA guidance recommends a supervised approach to pet weight loss rather than an improvised diet, since a plan that’s too aggressive or poorly balanced can cause its own health problems. Weight management typically involves:
- A veterinary check-up first, to rule out underlying medical causes of weight gain and establish a safe target weight.
- A specially formulated weight reduction food with correct levels of fat, protein and nutrients to support weight loss without leaving your pet feeling constantly hungry.
- Consistent, measured portions rather than estimating by eye, using kitchen scales where possible.
- A gradual increase in exercise appropriate to your pet’s current fitness and any existing joint issues.
- Cutting back on treats, or substituting a portion of their usual measured food allowance for treats rather than adding them on top.
This isn’t an exhaustive list of every consideration for every pet — individual health conditions, age and breed all affect what’s appropriate, which is why involving a vet at the outset matters.
Structured support programmes
For owners who want more structured support, PDSA runs Pet Fit Club, a six-month diet and exercise programme tailored and overseen by PDSA vets and nurses, alongside an annual Big Weigh In campaign encouraging owners to get their pet’s weight checked to help address the broader issue of pet obesity across the UK.
Getting started
If you’re not sure whether your pet is carrying extra weight, a free weight check at a vet practice is a straightforward first step — many practices offer this without requiring a full consultation. Catching gradual weight gain early makes it considerably easier to manage than addressing significant obesity once it’s established, both for your pet’s comfort and their long-term health.
Why treats deserve particular attention
Treats are worth singling out because they’re often where the biggest, least-noticed calorie contribution comes from. A single small dog biscuit or a spoonful of cheese might seem trivial in isolation, but relative to a small dog’s total daily calorie needs, treats given multiple times a day can add up to a significant proportion of intake without ever appearing on a “how much do I feed my dog” calculation based on their main meals alone. The same applies to cats given daily dental treats or a saucer of milk, which isn’t part of a cat’s natural diet and adds calories many owners don’t factor in.
A practical approach many vets recommend is treating your pet’s daily food allowance as a fixed budget, and taking treats out of that budget rather than adding them on top — using a portion of their normal kibble as training rewards, for example, rather than a separate treat entirely. This keeps the reward and bonding value of treat-giving intact while removing the hidden calorie creep that often drives gradual weight gain over months and years.
It’s also worth having an honest conversation with everyone in the household, including children, about treat-giving, since weight gain often results from several people each giving what feels like a small, reasonable amount without realising the combined total across the day.