The popularity of cats and dogs isn't the only thing that has grown in the last 20 years. So have their bellies.
Some veterinarians say Americans are feeding their pets to death without even knowing it.
Treats take the brunt of the blame, said North Carolina veterinarian Ernie Ward, author of a book released this year called Chow Hounds and founder of the Association of Pet Obesity Prevention. He calls treats "kibble crack" and "calorie grenades."
"We confuse food with love. In the dog world, what they want most is interaction and affection. It's not a cry for food, it's a cry for attention," he said.
The most egregious offense may be the "guilt treat" - those dropped by the handful when pets have to be left alone, said Marion Nestle, a nutritionist, New York University professor, and author of the 2006 book for humans called What to Eat. Her book with Cornell University animal nutrition expert Malden C. Nesheim, Feed Your Pet Right, is due in bookstores this month.
Experts agree that people and pets are fighting the battle of the bulge for all the same reasons - too many calories and carbohydrates and too little exercise.
The Association of Pet Obesity Prevention represents 400 clinics, or about 1,000 veterinarians. When polled last year, those vets said 45 percent of the dogs in their care and 57 percent of the cats were overweight or obese, defined as 30 percent above ideal weight.
The size of the country's cats and dogs hasn't gone unnoticed. About eight years ago, Guinness World Records eliminated its fattest cat and fattest dog categories because of the health hazards, spokesman Stuart Claxton said.
There are diet pet foods galore, gyms, personal trainers, masseuses, TV fitness shows, and now, even a reality show - Purina has just completed an online Biggest Loser for dogs.
The recently completed canine version, called Project Pet Slim Down, was run by veterinarian Grace Long, director of veterinary technical marketing for Nestle Purina PetCare. Webisodes will be available online this summer.
One of the show's biggest successes was Courtney and her owner, Michael Shaun Corby of Los Angeles.
Courtney, an 8-year-old shih tzu, "was starting to seem weak and tired all the time. I hoped to get a healthier, happier dog. And besides she didn't look as good in her fat clothes," Corby said.
The dog started the program weighing 19 pounds and shed 20 percent of her body weight. Since the project ended, Courtney has continued to lose.
"Courtney is like a teenager again. She is happy, really happy, and I didn't notice she wasn't happy until I saw her this new 'skinny self,' " Corby said.
Getting Courtney her svelte figure became a team project with friends, family, and houseguests. "It shocked me that she only needed half a cup of food a day. I had been giving her two cups each meal," he said. He posted signs all over the house telling others not to feed her. "Some friends had been known to give her chips and pizza," he said.
Pet owners can overfeed their animals by as much as 25 percent a day, Ward said. "It seems so innocent. You overfeed and you don't even know it," he said.
As a result, "we're raising the first generation of dogs that likely won't live as long as their parents," Ward said. "A cat's sagging stomach is a deadly ball and chain and a dog's thick midsection is a hormone bomb factory waiting to explode."
There is no law requiring calorie counts on dog food, Ward said. Purina is one of those companies that does it voluntarily. Some labels, especially those on treats, require a calculator and a scale to understand, Nestle said.
As a last resort for dogs (no cats allowed), there is the fat farm.
At K9s Only in Los Angeles, you can rent your dog time on a treadmill or sign it up for swimming lessons. Twenty minutes in the pool can be like a three-mile hike and save stress on an overweight dog's knees, co-owner Kelly Dorafshar said.
It doesn't come cheap: At K9s Only, which also provides day care, training, massage, and grooming, 30 minutes on the treadmill rents for $25.
Buffing up Fido or Fluffy will help the animal live longer so you have more time together, your vet bills will be lower, and the dog will be healthier and happier and experience less pain from diseases like arthritis, the veterinarians said.
Slimming them down will also help you slim down, Ward said. "This works on both ends of the leash."