Choosing Dry or Wet Food for Cats Makes Little Difference

MU Study Suggests that Weight Gain, Not Type of Diet, Contributes to Diabetes in Cats

Nov. 28, 2007

Story Contact:  Christian Basi, (573) 882-4430, BasiC@missouri.edu

COLUMBIA, Mo. – Although society is accustomed to seeing Garfield-sized cats, obese, middle-aged cats can have a variety of problems including diabetes mellitus, which can be fatal. The causes of diabetes mellitus in cats remain unknown although there has been a strong debate about whether a dry food diet puts cats at greater risk for diabetes. A new study from a University of Missouri-Columbia veterinarian suggests that weight gain, not the type of diet, is more important when trying to prevent diabetes in cats.

Because dry cat food contains more starch and more carbohydrates than canned cat food, some have argued that a diet containing large amounts of carbohydrates is unnatural for a cat that is anatomically and physiologically designed to be a carnivore. Carbohydrates constitute between 30 percent and 40 percent of dry cat food. Some have been concerned that this unnatural diet is harmful to cats and leads to increased incidence of diabetes. Wet cat food, on the other hand, is high in protein and more similar to a natural carnivore diet. 

In the study, Robert Backus, assistant professor and director of the Nestle Purina Endowed Small Animal Nutrition Program at MU, and his team of researchers compared a colony of cats in California raised on dry food with a colony of cats in New Zealand raised on canned food. After comparing glucose-tolerance tests, which measures blood samples and indicates how fast glucose is being cleared from the blood after eating, researchers found no significant difference between a dry food diet and a wet food diet. They also compared the results between cats less than three years of age and cats older than three. The MU veterinarian indicated that allowing cats to eat enough to become overweight is more detrimental to their health than the type of food they eat. 

“Little bits of too much energy lead to weight gain overtime,” Backus said. “We did find that cats on canned or wet food diets have less of a tendency towards obesity than cats on dry food diets.”

Forty percent of all cats in middle age are overweight or obese. According to Backus, male cats should weigh between 10 and 11 pounds, and female cats should weigh between 5.5 and 7.7 pounds. Besides diabetes, overweight cats are prone to other conditions such as skin diseases, oral diseases and certain cancers. When cats are spayed and neutered, they have a tendency to eat more and gain weight. Backus suggests monitoring the food even more closely at this time and not allowing the cat to eat in excess.

“The most effective thing you can do is be the one who determines how much your cat eats,” Backus said. “We have been conditioned to fat cats, but cats should have only between 18 percent to 20 percent body fat.”

Backus’ research was presented recently at the American College of Veterinary Internal Medicine Conference in Seattle.

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