Obesity is the most common nutritional disorder in companion cats, affecting an estimated 25-40% of the UK and US pet cat populations. Beyond cosmetic concerns, obesity causes significant welfare compromise through associated diseases, physical limitations, and reduced quality and length of life.
Obese cats face multiple welfare compromises: increased risk of diabetes mellitus, urinary tract disease, hepatic lipidosis, osteoarthritis, respiratory compromise, and dermatological problems. Physical limitations—inability to groom effectively, reduced mobility, difficulty grooming the perineum—cause discomfort and health problems. Life expectancy is significantly reduced. The cumulative welfare cost of feline obesity is substantial.
Neutering increases obesity risk substantially, reducing metabolic rate and altering appetite regulation. Indoor-only lifestyle reduces activity levels. Ad libitum feeding (food always available) removes satiety-based intake regulation in many cats. Highly palatable, energy-dense commercial diets in combination with reduced activity create a positive energy balance. Owner misperception of ideal bodyweight—normalisation of overweight cats—contributes to inadequate diet management.
Body condition scoring (1-9 scale, targeting 4-5; or 1-5 scale, targeting 3) provides systematic weight assessment beyond the weighing scales. Muscle condition scoring identifies muscle wasting concurrent with obesity (sarcopenic obesity—a particularly challenging clinical scenario). Baseline assessment before weight loss programmes monitors progress and prevents excessive muscle loss during caloric restriction.
Feline weight loss must be gradual—targeting 0.5-2% body weight per week maximum. Rapid weight loss risks hepatic lipidosis (fatty liver disease), a potentially fatal condition triggered by fat mobilisation during anorexia or excessive caloric restriction. Metabolic rate calculations determine starting caloric intake, typically at 80-85% of the target bodyweight's maintenance energy requirement. Veterinary-supervised programmes achieve better outcomes than owner-managed weight loss.
Prescription weight management diets reduce calories while maintaining nutrient density and satiety through high fibre and protein content. Transition to measured meal feeding (twice daily, measured portions) from ad libitum feeding is often necessary. Puzzle feeders increase feeding time, provide mental stimulation, and slow consumption rate. Multi-cat household feeding management prevents competition and inappropriate food access.
Increasing activity through interactive play (wand toys, laser pointers), enrichment feeding, and environmental complexity supports weight management. Indoor cats benefit from window perches, climbing opportunities, and rotating novel stimuli. While cats rarely exercise sufficiently to counteract dietary excess, increased activity improves metabolic health and quality of life during weight management.