Cutting Carbohydrates for Obese Cats

Nutritionists emphasize benefits of increasing protein levels in diets.


[From Tufts March 2010 Issue]

Today, more than one-third of cats in the United States are overweight, posing many health risks and possibly contributing to shortened lives.

Ongoing research indicates that increasing protein levels and decreasing carbohydrates in feline diets play vital roles in preventing obesity and its related illnesses. One of these leading scientists, Debra Zoran, DVM, associate professor and chief of medicine at Texas A&M University’s College of Veterinary Medicine and Biomedical Sciences in College Station, presented her research at the June 2009 conference of The American College of Veterinary Internal Medicine (ACVIM) in Montreal, Canada.

Sally Perea, DVM, Catnip‘s veterinary nutritional advisor and a senior veterinary nutritionist for Natura Pet Products, states, “Improvements in commercial cat foods have resulted in pretty good feline health overall. There aren’t a lot of nutritional deficiencies in pet cats anymore. Today’s problem is too much nutrition.”

Given that feline obesity is associated with urinary tract disease, heart disease, cancer, lameness, diabetes and premature death, owners are literally killing their cats with kindness.

“We recently saw a 7-year-old, 25-pound female cat at our referral clinic,” recalls Dr. Zoran.

Most cats shouldn’t weigh more than 10 pounds. Fearing people will purposely overfeed their cats, The Guinness Book of World Records no longer accepts applications for the “world’s fattest cat.” But a black-and-white cat named Mikesch surely comes close. In 2004, he tipped the scales at over 40 pounds — four times a healthy cat’s weight. Mikesch couldn’t clean himself and could barely walk. His elderly owner had been feeding him four pounds of ground meat per day.

Most feline obesity cases happen in less dramatic ways.

“Since there are few moving things to chase indoors, there’s little impetus for cats move around, other than to go to the food bowl,” says Dr. Zoran. “And all too often, owners keep that bowl filled with kibble, which is coated in fat and very tasty. That’s a recipe for ‘supersizing’ your cat.”

While pet food manufacturers can’t be blamed for overfed cats, the high quantity of grain in most commercial cat foods means high carbohydrate levels.

“Cats are obligate carnivores; they are genetically programmed to consume high protein and low carbohydrate levels,” says Dr. Zoran. “Excess carbs can be a source of energy for active cats. But in sedentary cats, they are stored as fat.”

Today’s carbo-loaded cats might do better on a high-protein, low-carbohydrate diet often called the “Catkins diet.”

“The theory is like the Atkins diet for humans — that converting protein to fat requires more energy than converting carbohydrates to fat, so eating more protein and fewer carbohydrates will burn off calories,” explains Dr. Perea.

However, notes Dr. Perea, “The success of any diet depends largely upon reducing total calorie intake. And even low-carbohydrate diets can result in weight gain if the cat is overfed.”

So, when reading cat food labels, check calories and look for primarily meat products, rather than grains, among the first ingredients. Companies that make high-protein, yet low-calorie dry food include Royal Canin and Nestl Purina, notes Dr. Zoran.

The body composition of a mouse can provide guidelines to good feline nutrition. A mouse is nearly half protein, nearly half fat, less than 10 percent carbohydrates, and about 75 percent water.

“By contrast, dry cat foods average around 35 percent protein, up to 50 percent carbohydrates, and only 10 percent moisture,” says Dr. Perea. “Because cats have a short gastrointestinal tract, some carbohydrates can be hard for them to digest. So for cats with gastrointestinal problems, grain allergies, diabetes or weight problems, a low-carbohydrate diet makes sense.”

Another factor is protein.

Says Dr. Zoran, “Current research shows that a high-protein diet — one in which 45 percent of the calories come from protein — reduces fat, but preserves muscle mass. That’s essential to healthy weight loss.”

But, she cautions, “If you cut the amount of food in half, you’re also cutting the protein in half. Starting out with a high-protein diet helps balance this out.”

So, must you share your steak dinner with your cat? Or worse, go shopping for mice? Rest assured that high-protein, low-carbohydrate diets for your cat need not involve prime rib or rodents. Suitable cat foods can be found at your local pet supply store.

What’s in the can?
Canned food is one solution. It is composed of about 75 percent water, making it closer to the mouse model than dry food. A typical 5.5 ounce can of high-protein, low-carbohydrate food contains about 165 calories. That’s about what an average cat should consume each day. By contrast, many dry foods contain 500 calories per cup.

“Some cats complain constantly if their rations are cut. This is hard on their owners, and can be a big obstruction to weight loss,” says Dr. Zoran. “Your cat will feel fuller on fewer calories with canned food than with dry food.”

But whatever diet you choose, recommends Dr. Perea, “Measure the amount you’re feeding, and be aware of how much your cat is eating.”

“My ultimate goal is not to treat obesity, but to prevent it,” says Dr. Zoran. “Three quarters of all household cats have constant access to food.”

She adds that obesity is much harder to reverse than to prevent.

“Few 25-pound cats will ever become normal-sized cats again,” she says. “Successful treatment is far more likely with a 15-pound cat.”

Since it’s not healthy for cats to lose more than four percent of their body weight per month, weight loss is by necessity a slow, tedious process — and sadly, many owners give up.

Don’t be one of them. Weight control is your cat’s ticket to a long, healthy life. Armed with knowledge, healthy food and willpower, you may discover your cat’s true slim — and healthy body shape.


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