Turning tubby tabby into fitter feline

It is estimated that more than 30 percent of dogs and cats are obese — not just overweight, but truly obese. That means they are hauling around30 percent or more of excess fat.

Sandra's cat Louie weighs 26 pounds. Sandra says Louie should weigh 12 pounds. That's like a man whose ideal weight is 175 pounds weighing 380 pounds! Sandra has been trying for four months to put Louie on a diet — only to have him gain a pound.

I must commend Sandra for trying to address Louie's weight. Obesity is a serious issue.

Let's start by addressing the fundamentals of weight loss. Simply put, weight will be lost if the intake of calories is less than the calories needed to maintain current weight. What could be easier? Just feed Louie less than he needs to maintain his weight and he'll shed the pounds. Unfortunately, it is not that simple.

Every creature is different as to how many calories it burns per unit time and how many calories it needs to support its weight. Calorie burning can be increased through exercise, but it can be difficult to force a cat to exercise consistently.

Because Louie is not a dog, we will not put exercise into our calorie-burning equation. Instead, we will come up with a feeding strategy designed for weight loss. When I design a weight-loss schedule, especially when the patient is morbidly obese like Louie, I first recommend a thorough physical evaluation and blood testing. This can help rule out possible metabolic problems that might be contributing to the weight problem. It is also important to help identify possible disease processes that may have developed as a result of his obesity. Diabetes and heart disease are possible.

Hopefully, Louie has no underlying disease and no secondary disease and we can proceed with restricting his calorie intake. In cases involving hugely overweight patients, I use a special prescription diet containing fewer calories per unit volume, less caloric density, while still maintaining bulk in the food. This helps fill the patient's stomach without the added calories of a regular diet. There are no over-the-counter diets that allow this amount of calorie restriction.

We start by figuring Louie will need about 30 calories per pound of body weight per day. This number is an average and, as I mentioned, every cat is different. We multiple the 30 by his ideal body weight — 12 pounds according to Sandra. So he needs 360 calories per day. Remember, that is to maintain ideal weight; we must subtract some amount from that number in order to reduce the body weight over time. I would back off from the 360 calories by about 120 calories per day and, knowing that fat has about 3,600 calories in one pound, we can expect a weight-loss rate over time.

In order to feed the recommended 240 calories we've calculated, we must know the caloric density of the food. In the case of the diet I mentioned, there are 260 calories in a cup. Therefore, Louie will need slightly less than one cup per day. Back to our calculations, 3,600 divided by 120 gives us a loss of about 1 pound of fat over 30 days. Thirty days times 14 pounds of needed fat loss gives us a total time of 420 days for Louie to reach his ideal weight. This is, of course, a dynamic calculation, as every cat is different. Knowing this, we will weigh Louie once a month and adjust his caloric intake.

Once Louie reaches his target weight, we can then put him on a maintenance diet containing approximately 360 calories per day. This can be any high-quality diet. Remember that this amount does not include any treats or other dietary intake.

One point to remember when beginning and maintaining a diet program for our pets is that they may not buy into the whole idea. They will use every trick to get you to feed them more. Stay strong, my friends, and know that what you are doing might just be saving your beloved pet's life.

Jeff Kahler is a veterinarian in Modesto. Questions can be submitted to Your Pet in care of LifeStyles, The Modesto Bee, P.O. Box 5256, Modesto 95352.