Weight Problems in Pet Animals
—Do Diet Foods Work?

     by Susan Wynn, DVM

The High Points

• Obesity is extremely common in our pets, for the same reasons it is common in people—too much food, too little exercise
• Dry commercial diets don't help the situation, because we tend to feed the bowl, not the animal—we have to actually measure amounts and count calories
• Canned or homemade foods help us with portion control, due to their expense and also their water content, or because they are like an "Atkins" type diet
• Using Kong toys and Buster cubes with bits of food in them helps keep your pet occupied but without getting many calories in return
• Veggies for dogs and catnip for cats are low-cal treats

Introduction

Did you know that the most common form of malnutrition in the USA is obesity? Our pets have followed suit; in one study, 21.4% of dogs surveyed were obese, and only 60.3% were at optimum weight. Some animals are more likely to become corpulent—Labradors, Dachsunds, Beagles, Shelties and Basset hounds are particularly prone, as are many neutered animals and some pets fed table scraps. Cats fed free choice easily become obese.

We all know the causes of obesity—too little exercise and too many calories. There are two other factors probably at work here. An individual's personality may affect his metabolism: placid, relaxed animals will gain weight more easily than pets with a lot of nervous energy. Genetic make-up also plays a large role. Although "hormones" are not a common cause (as you may have heard a friend or two say), illnesses such as hyperadrenocorticism, hypothyroidism, or over-medication with steroids may be associated with weight gain. As you can appreciate, some pets are simply going to lose and maintain their weight better than others.

Unfortunately, the pet food industry is partially to blame. Pet foods come in a wider variety of choices, for less money, than ever before. We have become accustomed to feeding over-large amounts of inexpensive food, filling big bowls and thinking that we are making our pets happy. "Weight loss" diets perpetuate the myth by allowing us to continue to feed large amounts of food that is just lower in calories. In truth, if pets ate "human-quality" foods with plenty of lean meat and less grain, the food would be less expensive and pets would be less likely to become overweight.

Obesity is a frightening disease because in addition to causing serous discomfort and body dysfunction, it exacerbates other diseases. Obese animals may have trouble breathing. Obese animals with heart or lung disease can have deadly trouble. Arthritic animals undergo needless discomfort when carrying extra fat around. Obesity is known to cause liver disease, hypertension, constipation, heat intolerance, and increased risk under anesthesia. With all these problems, it is easy to see why obese animals do not have life expectancies as long as usual. In addition, lean animals have better immune systems and don't form tumors as readily.

Getting started

How can you tell if your pet is overweight? The best rule of thumb is to feel around the ribs—if you can find them. Cats should look like a straight line from above and the sides. Dogs at optimum weight should have a waist, and you should be able to feel their shoulders as well (some dogs, like some people, actually accumulate fat in the shoulder area, making them appear to have a waist while they are, in fact, overweight). If you cannot find ribs, but can grab handfuls of fat, it is time to consider a weight loss program. Ask your vet to teach you how to do a body condition score, which is a semi-objective way for you to track your pet's progress.

When embarking on a weight loss program, you should encourage your pet to exercise as well as cutting his calories, although it is advisable to have your veterinarian complete a physical exam and to start slowly, just as people should do at first.

Problems with weight loss diets

Many veterinarians recommend commercial weight loss diets, and some of these work so well that they are available by prescription only. Dogs and cats do lose weight with these diets, if fed the proper amount, and if the animal's metabolism can handle the increased grain protein and fiber provided by the diet. One common problem that we see is a gradual degeneration in coat quality. Many animals tend to stay overweight and develop dry flaky coats (making animals on weight loss diets easy to spot). These low fat diets may take their toll on the animal's coat, but problems can go deeper than that.

Wet food, less of it

There are quite a few pets, however, who don't seem to lose weight well using low fat diets anyway. Recent research has indicated that increasing dietary fiber may NOT suppress appetite, and holistic veterinarians have found that these animals sometimes do better on canned food (even of the maintenance variety) or on home-prepared diets. In addition, if the protein in the diet is too low, the animal may somehow sense that, and want amounts above the label recommendation in trying to fulfill their protein requirements.

Perhaps the fact that canned or homemade foods contain more water, and so the calories are "diluted" out, is responsible for this finding that some pets lose weight and feel great eating them. Some pets may simply need more meat, and less grain, in their diets. Perhaps the secret is that canned foods force the owner to turn to "meal feeding," instead of allowing free choice feeding. In any case, try to find a canned diet that is high quality and free of preservatives. If you have a pet that is already on a weight loss diet, DO NOT switch back to maintenance diets; simply use the canned form of a weight loss diet.

Snacks and Entertainment

Snacks are an important part of life for some pets. Unfortunately, many "snack" foods for pets are fattening junk food like human favorites tend to be. Good alternatives for dogs include a variety of vegetables, while cats sometimes like fruits or catnip.

If your cat or dog begs for food, try diverting that behavior to something more constructive. When they beg, start a game with the laser pointer for your cat, or throw a ball for the dog. Dogs can be kept busy for hours with a Buster Cube—you can hide food in it, and as the dog works with it, rolls it around and in general worries the Cube, it occasionally releases pieces of food.

Obesity is a serious medical and nutritional problem, but consulting with your veterinarian can help you improve the quality of your pet's life for years to come.