(MNN) -- Plenty of people indulge their pets because it makes them happy and keeps the peace. But did you know that overweight cats and dogs can develop diabetes, just like humans do?

My sister's dog, Daisy, spent a six-month vacation at my home after the birth of my nephew. The 14-pound terrier enjoyed having free run of the house.

During her stay, Daisy also took great pleasure in tormenting my 48-pound dog, Lulu, and teasing Tonka, our 75-pound foster pooch. To keep the peace, I often fed Daisy first and then scooped out the same amount of kibble for Lulu and Tonka.

It wasn't until my brother-in-law visited that I realized the major flaw in my game plan. One look at his formerly miniature schnauzer and he asked, "What are you feeding her?"

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Daisy had been eating her own kibble and whatever Lulu and Tonka left behind in their bowls. I quickly resolved the situation by removing all three food bowls after mealtime, and taking everyone on regular walks around the neighborhood.

Soon Daisy dropped those extra pounds and regained her original girlish figure. Now she burns calories by playing fetch and hide-and-seek with my 18-month-old nephew.

Daisy's weight gain was a short-term problem, but a growing number of cats and dogs in the United States are losing their battle of the bulge -- just like their human companions.

In a 2009 study, the Association for Pet Obesity Prevention found that more than 58 percent of cats and 45 percent of dogs in the United States are overweight or obese.

Like people, overweight cats face a high risk of diabetes. Arthritis and decreased mobility also are symptoms of weight gain.

Often, clients don't take note of the excess pounds until the cat has trouble jumping on the couch or tackling its favorite tower. Overweight cats also have trouble with grooming, which can lead to skin issues.

As for dogs, those additional pounds make them more prone to arthritis. Join pain leads to decreased mobility, which means they tend to gain even more weight.

"It's a huge problem," says Dr. Jennifer Monroe of Eagle's Landing Veterinary Hospital in Georgia. "It's very easy to put a large bowl of food on the floor and leave it for the entire day, but that's really not how animals should be fed. They don't have to work for food, so their energy requirements are lower and they should not be fed as much."

While she has noticed an increase in overweight pets visiting Eagle's Landing, Monroe says that addressing the issue with clients can be tricky, especially when the owner is overweight.

According to the Centers for Disease Control and Prevention, more than one third of U.S. adults -- more than 72 million people -- are obese. From 1980 to 2008, obesity rates for adults have doubled.

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"I like to start off being honest," Monroe says. "I'll note that Fluffy is putting on a few extra pounds or getting a few extra treats. This opens the conversation about what they are feeding the pet. Once you get them open to the idea of discussing their pet's weight you can discuss obesity."

Often, owners are willing to take action when they understand that obesity can shorten a pet's life span. Monroe adds that many clients will do for their pets what they cannot do for themselves.

"Pets don't decide how much they will eat; we do," she says. "We have a responsibility to them as their caretakers to make sure they stay healthy. The best way to make sure they stay healthy is to keep their weight in a reasonable range."

To help veterinarians educate their clients about healthy weight ranges for cats and dogs, in 2008 the American Veterinary Medical Association created obesity prevention kits that contained educational resources and images of pets at a healthy weight.

The Association for Pet Obesity Prevention also educates pet owners about ideal weight ranges. Sixty-five to 80 pounds is listed as the ideal weight for a healthy Labrador retriever, while a healthy Persian cat should weigh between 7 and 12 pounds.

"We are so used to thinking overweight is normal, but we have to realize that is not normal," Monroe says. "We have sliding scales in every one of our exam rooms so we can show our owners what exactly we are seeing. We can show physical characteristics of a healthy cat or dog."

Of course, it's no secret that cats aren't exactly open to exercise, so veterinarians typically suggest dietary changes to control weight issues. But Monroe says humans can outsmart their feline companions with intense playtime.

Have a lengthy discussion with your vet about your pet's weight. Here are a few more tips to get cats and dogs in shape.

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Focus on play time: Don't just roll around on the carpet with your cat. Take about 20 minutes for some intense playtime. All you need is a flashlight, and perhaps some disco tunes.

Embrace the thrill of the hunt: Try a good chase around the house. "If you have a two-story house, start on the bottom floor and make them run up the stairs," Monroe says.

Interactive toys: Add low-calorie treats to slow-release or interactive toys. This makes your cat or dog work for its food. (The horror!)

Get crafty: Cat towers can help cats get moving. If you are crafty, try building your own kitty condo. Ehow.com offers tips to start this house project.

Step outside: For owners with limited mobility, slingshot toys provide an extra boost to outdoor games of fetch with the dog. Some toys even have slots for treats so that portly pups stay motivated.

Hit the pavement: Walking on a flat surface provides good, low-impact exercise for overweight dogs and people. Just be mindful of when your dog has had enough. Excessive panting may be a sign of overexposure.

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Table scraps require moderation: "I am a big fan of healthy and appropriate table scraps," Monroe says. "Where people get in trouble is feeding indiscriminately."

Dog food should comprise a day's worth of calories for your dog. Adding table scraps, such as a bite of fatty meat or pizza crust, can throw a day's calorie count.

"A bite of pizza for us is rather insignificant," Monroe says. "For a 15-pound Dachshund, that is an entirely different story."

Add veggies: Raw or cooked carrots, green beans or cauliflower make great table scraps.

"If you have a dog that has become accustomed to table scraps, you can do that without them feeling deprived, but it can take some time," she notes.

It helps to simmer veggies in vegetable or chicken stock.

Take a dip: If there is a safe place available, swimming provides dogs and their human companions an excellent workout that also eases achy joints.

Make friends: A pet that is well-behaved and vaccinated can burn a few calories running around at the dog park. Got treats? Break your pet's favorite treats up into smaller pieces for distribution.

"With dogs, the size of treat doesn't matter," Monroe says. "They will swallow in one bite anyway. They still think they are being treated several times."

Morieka Johnson writes about pets, fashion and money-saving ideas for MNN.com. You can follow her and many other green writers on Twitter @MotherNatureNet.

© Copyright 2011 Mother Nature Network

© Copyright 2011 Mother Nature Network