Saturday is National Cat Day, and while you are hugging your feline in celebration, take a moment to assess the girth of your furry friend.

Nearly 60 per cent of cats in North America are obese, which University of Guelph researchers say is a serious health issue.

“People have the image of Garfield in their minds,” said Moran Tal Gavriel, a D.V.Sc. candidate in the Department of Clinical Studies in the Ontario Veterinary College (OVC).

“They think that big cats are cute, but it’s not healthy.”

Few owners ask veterinarians whether their cats are a healthy weight, she said.

Tal Gavriel and graduate student Bianca Di Sabatino are studying whether weight loss can help return fat cats to optimal health.

They’re comparing gastrointestinal (GI) bacteria of obese cats before and after weight loss with gut samples from healthy lean cats.

Obese cats — and people — have higher levels of two kinds of bacteria involved in metabolism, called firmicutes and bacteroidetes.

GI bacteria absorb energy from food, causing obese cats to gain more weight from the same amount of food than lean cats, said the researchers. Obese cats absorb more nutrients and continually gain weight.

Worse, these bacteria may cross the intestinal wall and cause inflammation or infection. That can lead to secondary diseases such as diabetes and osteoarthritis.

The team has found that cats are more active, vocal and affectionate after losing weight.

The researchers used a low-calorie, high-nutrition diet to examine GI bacteria changes.

The researchers say it’s important to follow a veterinary-prescribed diet for feline obesity.

Rapid weight loss is dangerous for cats, as it can cause excess fat to move into the liver. That puts strain on the organ and can lead to liver failure.

This research was sponsored by the Natural Sciences and Engineering Research Council of Canada and Hill’s Pet Nutrition.

Collaborators are Adronie Verbrugghe, a clinical studies professor and holder of the Royal Canin Veterinary Diets Endowed Chair in Canine and Feline Clinical Nutrition, and Prof.  Scott Weese, Department of Pathobiology.