Pet obesity is now the most common nutritional disorder in UK cats and dogs. The PDSA estimates that 51% of dogs and 44% of cats in the UK are overweight or obese. Carrying excess weight does not just reduce quality of life — it significantly increases veterinary costs over your pet's lifetime.

Health Risks of Obesity

Overweight pets are at increased risk of:

  • Osteoarthritis: Excess weight puts additional strain on joints. Obese dogs develop arthritis earlier and more severely than lean dogs.
  • Diabetes: Obese cats are 4 times more likely to develop diabetes than cats at a healthy weight.
  • Heart disease: Excess fat increases the workload on the heart.
  • Breathing problems: Particularly dangerous for brachycephalic breeds that already have compromised airways.
  • Reduced lifespan: A landmark study showed that lean Labrador Retrievers lived on average 1.8 years longer than their overweight siblings.
  • Increased surgical risk: Anaesthetic is more dangerous in obese pets, and surgical wounds heal more slowly.
  • Urinary disease: Obese cats are at increased risk of feline lower urinary tract disease.
  • Cancer: Some studies link obesity to increased cancer risk in pets.

The Extra Vet Costs of Obesity

While there is no single UK study quantifying the full cost, the associated conditions add up:

  • Arthritis treatment: £200–£1,500/year
  • Diabetes management: £800–£1,800/year
  • Increased anaesthetic charges: Many vets charge more for anaesthetising overweight pets (10–20% surcharge)
  • More frequent vet visits: Obese pets typically visit the vet more often for weight-related conditions
  • Higher insurance premiums: Some insurers now ask about weight and may adjust premiums accordingly

A conservative estimate suggests overweight pets cost their owners £200–£1,000 extra per year in weight-related veterinary care.

Weight Management Options and Costs

Veterinary weight clinic: Many practices run free or low-cost weight clinics, often staffed by veterinary nurses. These provide weigh-ins, feeding advice, and progress monitoring. Cost: £0–£30 per session.

Prescription weight-loss diets:

  • Hills Metabolic, Royal Canin Satiety, Purina OM: £30–£60/month for dogs, £20–£40/month for cats
  • These diets are clinically proven to achieve safe weight loss while maintaining muscle mass

Standard reduced-calorie diets:

  • "Light" versions of regular pet foods: £20–£40/month for dogs, £15–£30/month for cats
  • Less effective than prescription diets but cheaper

How to Help Your Pet Lose Weight

  • Measure food accurately: Use kitchen scales, not scoops. Most owners significantly overfeed.
  • Cut treats: Treats should be no more than 10% of daily calories. Many owners unknowingly give 30–50% of calories as treats.
  • Increase exercise gradually: For dogs, add 5 minutes per walk per week. For cats, use interactive toys for 15–20 minutes daily.
  • Weigh regularly: Monthly weigh-ins at the vet (usually free) help track progress.
  • Address all feeders: Every family member must follow the same plan. One person "sneaking" treats undermines the entire effort.

How to Tell If Your Pet Is Overweight

Use the body condition score (BCS) system: you should be able to feel (but not see) your pet's ribs without pressing hard. Viewed from above, there should be a visible waist (narrowing behind the ribs). From the side, the belly should tuck up behind the rib cage, not hang down.

If in doubt, ask your vet or veterinary nurse for a body condition assessment. This is usually free and takes 2 minutes.

Last updated: March 2026. Sources: PDSA Animal Wellbeing Report, BSAVA guidelines, VetCost pricing data.