Cat Health
Cat Obesity UK — Body Condition, Diet & Indoor Cat Weight
Published Last updated 3 min read
Quick answer
Obesity affects a large proportion of UK pet cats, especially indoor-only cats. Weigh food on scales, limit treats, encourage play hunting daily, and ask your vet for a body condition score. Never crash-diet a cat — rapid weight loss risks fatty liver disease.
Obesity risks for UK cats
According to the PDSA and RSPCA, overweight cats face higher rates of:
- Diabetes mellitus
- Urinary tract disease and cystitis
- Osteoarthritis — harder to detect because cats hide lameness
- Liver disease during inappropriate weight loss
- Reduced grooming and skin problems
- Anaesthetic complications if surgery is needed
Indoor cats burn fewer calories but often receive the same portions as outdoor cats. Neutering reduces energy needs — adjust feeding after surgery. See Cat neutering UK.
Body condition scoring
According to Blue Cross guidance, assess your cat at home:
| Sign | Healthy weight |
|---|---|
| Ribs | Felt with light pressure — not protruding |
| Waist | Slight inward curve behind ribs when viewed from above |
| Belly | Primordial pouch may hang — distinguish from overall roundness |
| Spine | Palpable but not sharp |
Vets record body condition score (BCS) at visits. Ideal is typically 4–5 on a 9-point scale. Long-haired cats hide weight visually — feel the body weekly.
Feeding routines that work
According to the PDSA, practical UK feeding strategies include:
- Weigh kibble or wet food — measuring cups are inaccurate
- Split meals — two or more smaller meals reduce begging
- Treat budget — maximum 10% of daily calories; use kibble from the allowance
- Avoid human food — dairy, tuna in oil and leftovers add hidden calories
- Multi-cat feeding — separate bowls in different rooms; microchip feeders help in some households
Automatic feeders can dispense measured amounts when you are at work. Free-feeding dry food suits some lean active cats but commonly contributes to weight gain in sedentary indoor cats.
Prescription weight-management diets from your vet provide balanced nutrients at lower calories — important because simply cutting normal food risks nutrient deficiency.
Activity for indoor cats
According to the RSPCA, environmental enrichment supports weight control:
- Play sessions — 5–10 minutes, two or three times daily with wand toys
- Vertical space — cat trees encourage climbing
- Puzzle feeders — dry food in activity balls slows eating
- Rotating toys — novelty maintains interest
Outdoor access increases activity but carries road, fight and disease risks — weight management must not rely on unsupervised roaming. Secure catios and harness walking suit some UK cats.
Veterinary weight clinics
According to the BVA, vet nurse weight clinics offer:
- Starting weight and target on practice scales
- Fortnightly check-ins
- Adjustment of calorie plans based on rate of loss
- Screening blood tests if diabetes or thyroid disease is suspected
Safe loss is roughly 1–2% of body weight per week — slower than many owners expect. A cat that loses weight too quickly needs immediate vet review.
Medical causes to rule out
Weight gain despite controlled feeding, a pot-bellied appearance with thin legs, or increased thirst and urination warrant blood and urine tests. Hypothyroidism is less common in cats than dogs; hyperthyroidism usually causes weight loss — but overall body composition still needs professional assessment.
Sources & further reading
Facts in this guide are rewritten in plain English from publicly available UK advice. We name the organisation where a specific point comes from their guidance. Links below go to the original pages — use them to read the source material directly.
PETHEALTH+ is independent. These organisations do not sponsor, approve, or partner with this website. Guidance checked against sources listed below (last updated 2026-06-25).
Related guides
Frequently Asked Questions
- How do I tell if my cat is overweight?
- Feel the ribs — they should be palpable with slight fat cover. Look for a waist behind the ribs when viewed from above. A hanging belly flap (primordial pouch) is normal in many cats; overall body shape and vet body condition scoring matter more.
- How much should an indoor cat eat?
- Follow the feeding guide on your cat food as a starting point, then adjust to maintain lean body condition. Most adult indoor cats need fewer calories than active outdoor cats. Weigh food daily and count treats.
- Is it safe to put a cat on a diet?
- Yes, but only with veterinary guidance. Rapid weight loss can cause hepatic lipidosis (fatty liver), which is life-threatening. Safe plans aim for gradual loss over months.