Living (Too) Large

Increasing numbers of dogs and cats are packing on too many pounds. Here’s a look at what’s behind the excessive heft.

Once a whopping 21 pounds, Mishka now weighs a relatively trim 15. But there’s still more waddle in her stride than the family vet desires. So, the 11-year-old Boston Terrier not only spends time on an underwater treadmill several times a week, she also navigates through a field of stationary poles, uses an exercise ball and takes short walks on different textured surfaces—all to keep fit and avoid further weight gain.

The exercises, split between the University of Florida’s Small Animal Hospital in Gainesville and Affiliated Veterinary Specialists (AVS) in Maitland, also help with Mishka’s congenital knee problems, which have required multiple surgeries over the years. On May 1, she even made a bit of canine history, says her owner, Orlando businessman Dave Heine, as one of the few dogs in Central Florida to undergo a partial knee replacement, performed by Dr. Antonio Pozzi, the UF animal hospital’s orthopedic surgeon.

Although medically Mishka’s story contains several other threads, such as an autoimmune condition that causes her body to lose protein, her battle of the bulge reflects a growing national trend: a huge spike in the number of overweight cats and dogs that veterinarians see. 

According to the Association for Pet Obesity Prevention, some 44 million dogs and 58 million cats are overweight, or roughly half of dogs and nearly 60 percent of the cat population in the United States. Many of them are not just too heavy, but classified as obese. And, as with their human counterparts, obesity carries considerable health risks, including diabetes, joint issues, liver disease and even heart failure.

“We see lots of very overweight animals,” confirms Dr. Richard Hill, chief of the small animal internal medicine service at UF’s Gainesville hospital. “On a scale of 1 to 9, with 1 being very thin and 9 being very fat, sometimes we say they look like a 10 or 11!”

As dogs and cats get older, they tend to gain weight, much like middle-aged people, he says, although the principal reason behind increasing pet heft lies in overfeeding. Hill calls obesity the “number one nutritional disease of pets in First World countries.” Cats and dogs are equally prone to packing on unwanted pounds when their owners feed them too often, or too much. Veterinarians describe the problem as “free-feeding,” when owners leave food about the house, constantly available for nibbling or grazing. Dry food, especially, packs a high-caloric punch.

At Cat Depot in Sarasota, Lynn Rasys, the no-kill shelter’s director of communications, describes “Tiger” as a probable free-feeder. The eight-year-old gray striped cat, who passed away recently of liver failure, made national headlines, tipping the scales at 35 pounds—triple the size of a normal feline.

“Surprisingly, he didn’t have diabetes,” Rasys says. But his outsized bulk kept him in the shelter’s “chubby cat” pod until his adoption, when staff members literally had to wheel him out to the new owner’s car. 

Dr. Cheryl Tano weighs a portly feline patient. ROBERTO GONZALEZ

Diabetes develops differently in dogs and cats, according to Hill and other experts. While dogs may develop Type I diabetes, in which the body does not produce insulin, obese cats tend toward Type II, in which they still produce some insulin but not enough to control blood-sugar levels efficiently. Why this happens, “we’re not sure,” says Hill, but researchers hypothesize that a fat-derived hormone, known as adiponectin, goes down over time in obese cats and people, but not in fat dogs, perhaps accounting for their differing disease patterns.

Cats and dogs differ in another way. In cats, a high-protein diet can sometimes reverse the diabetic condition, says Dr. Kristin Olsen, an internal medicine specialist at AVS. “But in dogs, once they become diabetic, they stay so.”

In any overweight pet, certain health issues that can contribute to a weight problem should be ruled out first, say Olsen and other veterinarians. These include hyperthyroidism and Cushing’s Disease, where the adrenal glands release too much of a stress hormone, stimulating appetite. “This is more of a dog problem than a cat problem,” Olsen says. “Cats are more likely to just overeat.”

Pudgy or overweight dogs also face more structural issues than cats. Large breeds, especially, often develop hip or knee problems, as these joints strain under the wear-and-tear of extra pounds, Olsen says, while smaller breeds may develop breathing problems, as extra weight weakens their airways.

Although obesity poses potent heart risks in people, its impact on dogs and cats in that area is considered relatively slight. Neither dogs nor cats develop atherosclerosis—a hardening of the arteries—or blood clots, says UF’s Hill, although some cats, especially Maine Coons, tend toward heart failure as the heart muscle thickens. The reason for this discrepancy has to do with major differences in the way dogs and cats handle fat, he says. While in a human, two-thirds of cholesterol lies in LDL (low-density lipoproteins), the so-called “bad” cholesterol, it’s the reverse in cats and dogs, with two-thirds of cholesterol in HDL (high-density lipoproteins) or “good’ cholesterol.” And that may provide some protection, Hill says.

The upswing in pet obesity mirrors that seen in the human population. The Centers for Disease Control and Prevention defines one in three adults over age 20 in the U.S. as obese, a measurement of height and weight that correlates with body mass index or BMI. A BMI over 30 is considered obese.

But so far, there is little data showing a relationship between pet owners’ size and the size of their overweight pets. Dr. Cheryl Tano, an AVS surgeon, says she found only one published paper showing a connection in dogs, nothing in cats. Still, the health benefits of both owner and owned staying fit are obvious, and one study even shows a slight survival edge for dogs fed a restricted diet over many years, Tano says.

So, watching "calories in, calories out," remains a good strategy for helping both dogs and cats shed unwanted pounds, along with regular exercise, if orthopedic or breathing issues don't make it too difficult to do. When that happens, Olsen says, “it's good to come to a place like ours" for physical therapy.

Overfeeding is another matter. “Dogs don't go into the fridge and get their own food," Tano says. "You need to switch to healthier options." 

She says pet owners need to establish a feeding schedule and stick to it. For dogs, shy away from treats and replace them with green beans, carrots and even broccoli, which dogs seem to love, she says. Cats on the other hand, as natural carnivores, need a high-protein diet.

Hill, too, emphasizes the importance of dietary control. “The most important thing is to feed them less, to reduce caloric intake by a third, which should be done under the supervision of a veterinarian.”

Dr. Kelly Fishman supervises Mishka’s workout on an underwater treadmill at UF’s Small Animal Hospital. UF COLLEGE OF VETERINARY MEDICINE

As for Mishka, Heine readily admits he and his wife, Tatia, have spoiled her. “She loves her table food,” he says. 

But because she’s a medium-sized terrier, they worried less about her weight than her knee problems, until recently. High-dose steroids for her inflammatory bowel disease made her very hungry, Heine says, and her weight fluctuated widely over the past several years.

Keeping Mishka’s weight stable since her latest surgery is critical to her health, so the couple remain vigilant about her appointments. Mishka also gets acupuncture for pain.

Although Heine says he carries pet insurance, Mishka’s healthcare costs in her decade-plus life have run well into the thousands, not to mention the time spent chauffeuring her to various therapies. But Heine clearly feels nothing is too good for his beloved pooch.

“She has no idea she’s actually a dog,” he says, laughing. “Don’t even use the word ‘dog’ around her, or she’ll growl.”