Who let the dogs pig out?

Victoria Stilwell, celebrity dog trainer and host of Animal Planet’s TV series It’s Me or the Dog, is seen in an undated handout photo.

NEW YORK (Reuters) - Someone once said that if your dog is fat you're not getting enough exercise.

So it's no surprise that as human obesity rates soar, man's best friend is loyally packing on the pounds as well.

"Overweight people are more likely to have overweight dogs," said Victoria Stilwell, dog trainer and author of "Fat Dog Slim: How to Have a Healthy, Happy Pet."

Over 34 percent of people in the United States are considered obese, according to the National Center for Health Statistics. Most estimates say up to 40 percent of household pets are overweight.

"An overweight dog shows real negligence by the owner. There's pressure on the bones and the heart and the organs. It's just not pleasant," she said.

"If a dog doesn't get enough exercise behavior problems such as anxiety, chewing, destruction, excessive barking, house soiling, can occur" said Stilwell, who hosts the Animal Planet television show "It's Me or the Dog."

In the show the British-born ex-actress comes to the rescue of pet owners driven to wits' end by dogs behaving badly.

"Really understanding your dog's experience of the world makes training easier," said Sitwell, who tries to see the world from a canine perspective.

"It's weird for them to be living in our domestic environment," Stilwell explained. "Why can't they toilet where they want? Why can't they jump up? Bark? Why can't they chew?"

Wayward pets are re-educated with positive reinforcement techniques. Neither hands nor voices are raised.

Stilwell says Sadie, her chocolate Lab, is living proof that a fat dog can get slim.

"When I rescued my dog two years ago she was extremely fat," she explained. "It took me a year of feeding her a very good quality diet and exercise to get 20 pounds (nine kilos) off her."

She suggests the exercise fit the breed.

"A Labrador Retriever is going to like retrieving. Dachshunds are tunnelers. And terriers want to negotiate to get to the toy rat. If your dog is a hunter you can hide toys in the garden," she said.

Dr. Nicholas Dodman, a veterinarian and animal behaviorist at the Cummings School of Veterinary Medicine at Tufts University, in Massachusetts, calls food and exercise the yin and yang of pet care.

"It's a lifestyle problem that leads to a sort of mental funk," he said. "The dog, who is at home, sometimes alone with very little to do, becomes bored and depressed. Eating becomes the only pleasure in life."

Dodman, author of "The Well-Adjusted Dog," blames the owner. "He (the dog) hasn't got opposable thumbs, he can't go to the refrigerator and take out a pork pie in the middle of the night. He eats what you give him."

His motto is -- a tired dog is a good dog.

"It's the owner's duty to provide a minimum of 30 minutes of cardio-type exercise," he said.

Dodman said felines also need 30 minutes of daily play.

But unlike their dog-owning counterparts, couch potato cat people can stay put.

"You don't have to rush around. Just shine a laser light or throw a ping pong ball. Cats will chase moving things."

On the subject of felines, Stilwell is stymied.

"Cats are a little beyond me," she admitted. "Cats are a different bowl of fish."