Just like their human masters, a majority of American pets have a weight problem, according to a study.

In its fourth yearly study of how fat Americans’ four-legged furry friends are, the Association for Pet Obesity Prevention found that 53 per cent of cats and more than 55 per cent of dogs were overweight or obese.

That means there are around 50 million fat cats and 43 million pudgy dogs in the US.

The study looked at 133 adult cats and 383 dogs.

Nearly a third of the cats were classified by their veterinarians as overweight and nearly 22 per cent were deemed to be clinically obese, the study found.

Among the canines observed, 35 per cent were found to be overweight and 20.6 per cent were obese.

“We’re seeing a greater percentage of obese pets than ever before,” said Ernie Ward, founder of APOP.

In 2007, roughly 19 per cent of cats and a mere 10 per cent of dogs were found in the APOP study to be obese – defined for the family pet as having a body weight that is 30 per cent greater than normal.

“This is troubling because it means more pets will be affected by weight-related diseases such as arthritis, diabetes, high blood pressure and kidney disease,” the same illnesses that afflict obese humans, Dr Ward said.

American cats and dogs are doing slightly better, in obesity terms, than their masters and mistresses, around one in three of whom is obese.