Are cats getting heavier? Pet owners and veterinarians have wondered for years. Now, researchers at the University of Guelph have pioneered the largest analysis to date, drawing on data from more than 19 million cats to map typical weight gain and loss across their lifetimes. Their findings show that most cats steadily gain weight with age, with averages peaking around eight years—even after outgrowing kittenhood.
The team examined 54 million veterinary weight records, accounting for variables like sex, neuter status, and breed to ensure robust insights.
Male cats reached higher peak weights than females, while neutered cats outweighed intact ones. Among popular purebreds (Siamese, Persian, Himalayan, and Maine Coon), peaks occurred between six and ten years. For domestic shorthairs, it was after eight years.
Notably, average weights for neutered eight-year-old domestic cats rose from 1995 to 2005 but stabilized between 2005 and 2015.
The study also highlighted a concern: 52% of cats had just one recorded weight, possibly indicating irregular vet visits or clinic changes.
