12 Overweight Rats, Dogs and Cats Compete in 'Biggest Loser' Competition for Pets

Organizers hope the competition will help encourage pet owners to help their animals maintain a healthy weight.

This challenge is for the toughest of the fluffiest.

Welcome to "The Biggest Loser: Fur Ball Edition," where 12 of the U.K.'s most overweight animals will go paw-to-paw in a weight loss competition.

Mr. T, an oversized rat, weighs a whopping two pounds, more than four times the weight of an average rat. His goal for the challenge is to shed half his weight, to a healthier one pound.

The fat rat will be going against Billy, a 25-pound Shih Tzu; Bella, a 52-pound beagle; Pollyanna, a 25-pound pug and Benji, a 25-pound cat that can no longer fit through the cat flap on its owner's door.

During the weight loss competition, held through the People's Dispensary for Sick Animals' (PDSA) Pet Fit Club, will include a six-month diet and exercise program tailored specifically to each animal's needs.

"Pet obesity is an epidemic that is seriously impacting the lives of millions of pets across the country," veterinarian Olivia Anderson-Nathan said. "As with humans, carrying excess weight has serious health implications for our four-legged friends.”

Pet Fit Club, a non-profit animal weight loss clinic, hopes their latest competition will encourage pet owners to help their animal companions be their healthiest selves.

To follow the competition, visit their website.