Of 143 veterinarians questioned by the Royal Society for the Prevention of Cruelty to Animals for the report, 80 percent reported a steep rise in the number of cases of overweight pets.
More than three quarters — 76 percent — had started special fat clinics to reduce the girth of pets.
One owner in three of 2,300 questioned acknowledged that their four-legged friend was too fat. For cats, the figure was above 50 percent.
One man used to feed his dog a breakfast of egg, sausage and bacon until it became so fat it could not move and had to be put down. He was banned for life from keeping animals, the Royal Society for the Prevention of Cruelty to Animals said.
"People who let their pets starve are labeled cruel and callous, but what people don't realize is that overfeeding your pet can cause just as much suffering as starving it," Grant said.
"A fat dog may look cute and cuddly but in reality you are killing it with kindness. An animal only needs to be slightly over its ideal body weight for health problems to begin," he said.
"If you think your pet is overweight, consult your vet today and show your animal that you really do care about them."
