Feline obesity is a problem for one in three domestic felines. It is a metabolic disease that can be prevented by proper diet and exercise. The problem with obesity that few people realize is that fat cells never go away. They can shrink, grow larger, or proliferate, but they never really disappear. These cells are also metabolically active, making hormones such as anti-insulin hormones, pro-inflammatory proteins, leptin (increases glucose intolerance) and many others.

There are a number of diseases seen in felines today that are directly related to obesity. Some of these diseases include, but are not limited to, diabetes, arthritis, hepatic lipidosis, and feline lower urinary tract disease.

A number of situations can lead to obesity, but the two main causes are 1) ingesting too many calories and 2) not getting enough exercise. Food should be reduced by 1/3 at the time of the patient's spay or neuter, because anti-insulin hormones and leptin will begin to increase after neutering and predispose the cat to obesity. A good fact to remember when deciding how to best feed your pet is that for every teaspoon of food that is added to their daily diet, a cat will gain 1 pound! Cats eat by volume, not by calories. Increasing the water content of their food will help to ensure they remain full and satisfied while cutting out calories. The amount of food intake must be controlled—cats should not be fed free choice—and an exercise plan established in order to keep the pet healthy. Problems can be identified early by monitoring the pet’s weight.

Cats are special creatures. They utilize protein, not carbohydrates, for energy. When a cat is placed on a diet that is low in protein, they lose lean body mass and keep the fat. Their bodies do not have the enzymes needed to digest carbs, and their intestine is much shorter than an omnivore's. Their small intestine has more bacteria in it than that of dogs or humans. These bacteria digest protein and fat, but again, not carbs. In addition, cats' liver enzymes cannot handle large amounts of glucose. In young cats with diarrhea or cats with intermittent gastro-intestinal signs, high protein / low carb diets can be helpful.

Most dry foods have been associated with obesity. Dry cat food is a carbohydrate that has been sprayed with animal digest. Think donuts: carbohydrates covered in fat. The best high protein/low carb diets are canned kitten foods or Hill’s M/D, Purina D/M and Purina O/M. Of these foods, only Purina O/M is also low calorie. Controlling portion size is essential with any diet. Most cats should be fed at least 50% canned food. This will reduce the quantity of carbs they ingest as well as control the calories and increase water consumption. When doing any diet change, please remember that it can take up to six months for a diet change to take effect.