"Puff is the biggest cat I've ever seen," Clair said. "I know she was quite stressed while living with her previous owner, which may have led to her over-eating or not getting enough exercise. She was even too big for the cat carrier so we had to use a dog cage to bring her home."
Clair said she has tried to place Puff on a healthier diet for the past year, which has helped her lose about 5 pounds, but told The Dodo that she is still very determined in trying to sneak extra food.
"I'm strict with what she eats but she's determined — I've caught her eating the fish food from the fish tank before," she said.
Puff is competing with four other cats, six dogs and a rabbit in Pet Fit Club, a six-month diet and exercise program that awards a winner based on the amount of progress the mates make over that period of time.
"Each year we select a number of overweight dogs, cats and rabbits from across the U.K. to participate," Jessica Wassell of the PDSA said. "They are put on a diet and exercise program at their local PDSA pet hospital and attend monthly weigh-ins to track their weight loss."
