Obesity in Cats and What to Do

Obligate carnivores are designed to meet their energy needs with a high protein, moderate fat diet with little to no carbohydrates. Carbohydrates are minimally used for energy and those that are not used are converted to and stored as fat. The so-called “light” diets that are on the market have targeted the fat content as the nutrient to be decreased. The choice is then to raise either the protein or carbohydrate content of the diet, or both. Since animal-based protein (meat and organs) is more expensive than carbohydrates (grains/potatoes/peas), pet food manufacturers raise the carbohydrate levels in these foods making them very species-inappropriate and unhealthy. An optimal weight loss diet should be: high in protein (over 40% of calories), moderate in fat (under 50% of calories), low in carbohydrates (under 10% of calories), and high in water. When looking at the Cat Food Composition chart, you will note that there are not many examples of this profile. Why? Because fat is cheaper than protein. The calories from protein + fat + carbs must = 100%. If the carbs are kept below 10%, that leaves 90-95% of the calories to be divided between protein and fat. Protein is expensive. Fat is cheap. Therefore, low carb diets are usually high in fat. Examples of nice profiles include Friskies Classic Pates, some Fancy Feast varieties, Weruva Paw Lickin' Chicken, Tiki Puka Puka Luau, and Tiki Koolina Luau. You will notice that many of the higher protein diets are fish-based but it is not a good idea to feed fish to cats. Or, at least not as their main diet. Fish can be high in mercury, high in PBDEs (fire retardant chemicals linked to hyperthyroidism), high in phosphorus (not good for older cats' kidneys) and can be very addicting. It is best to feed poultry-based diets to cats. Water content of the diet is very important. Studies have shown that cats lose weight much easier on canned food versus dry. Dry food is very calorically dense and is high in carbohydrates which are not as satisfying to a cat as protein is. Many cats on the commercial 'light' or 'less active' diets either do not lose weight or do lose weight but also lose muscle mass along with the loss of fat. This is not our goal. The goal is to lose fat while maintaining muscle mass. In several studies, cats fed a high protein/low carbohydrate diet lost weight but maintained their lean body mass in comparison to cats fed a high carbohydrate/low fat diet. Many caretakers feed very small amounts of these "light" diets hoping that their cat will lose weight. However, feeding a small amount of a diet that is inappropriate for the species is not the answer! The caretaker often ends up with either a crabby, overweight cat or a thinner cat that may have lost too much muscle mass. See Molly’s and Bennie’s story of weight loss on this site's Feline Obesity page to read about how these sweet cats went from inactive obese cats that could barely walk or clean themselves to healthier, happier felines. Molly had great difficulty walking and cleaning herself due to her obese condition which was brought on by the consumption of dry food. Kittens, however, loved using her for a pillow. Molly’s veterinarian had prescribed Hill's Prescription dry r/d for her and instructed her caretaker to feed Molly only very small portions - and to put a shock collar on her to keep her away from her housemates' food. This is obviously not sound - or humane - obesity management advice. Hill's Prescription r/d is a very poor quality, high carbohydrate (35%) diet that contains the following inappropriate and unhealthy ingredients including a high level of fiber which a feline intestinal tract is not designed to process