Characteristics of a Good Reducing Diet
Holly Frisby, DVM, MS
Veterinary Services Department, Drs. Foster & Smith, Inc.
Essential to a good weight reduction program is reducing the calories fed, but how much? Most weight loss protocols for cats recommend feeding 75% of the energy needs your cat would need when he is at his ideal weight. There is extreme variability (up to 20%) in the actual energy of pets of the same weight, since their activity level can vary greatly. For this reason, the cat's response to the weight reduction program is monitored and adjustments made as necessary.
Regular food or diet food?
There are two basic ways to cut down on calories. One is to feed less of the food the cat is currently eating. The second is to switch to special weight reduction diets. And of course, with either way, table scraps are a no-no and treats need to be minimized.
There are several advantages to feeding a balanced commercial weight reduction diet. First, weight reduction diets are generally high-fiber, low-fat diets which have a low energy density and allow a greater loss of body fat than simply feeding smaller amounts of a high-fat diet. This is because fat contains over twice as many calories as protein and carbohydrates and low-calorie dense foods tend to produce satiety (a feeling of being full) at a lower level of calorie intake. In addition, more energy is used in digesting and absorbing low-fat, high-fiber diets. Finally, by reducing the amount of the food currently being fed, you are also decreasing the level of protein, vitamins, minerals, etc., the cat is receiving. These differences could be eliminated by using supplements, but it is something an owner should be aware of.
There are some instances in which feeding less of the current diet is preferred. If a cat is already on a special diet because of another medical condition (e.g.; bladder stones), it would be beneficial to maintain the pet on that diet. In some instances, the restricted availability of special weight reduction foods or their increased cost may make feeding less of the normal diet more appealing to the owner.
There are many weight reduction diets available and include Hill's Prescription Diet r/d and w/d, Waltham's Calorie Control Diet, Innovative Veterinary Diet's Hifactor Formula, Purina's OM-Formula, and Eukanuba's Reduced Fat Formula. In addition, there are 'grocery store' brands which market themselves as weight reduction or weight control diets. Many pet foods claim to be diet foods and nutritionally balanced. To be sure your cat is receiving adequate nutrition while on a weight reduction diet, consider some of the guidelines below.
Fat
Fat is the most calorie dense nutrient; fat provides over twice as many calories per gram as carbohydrates or protein. The fat, then, is what needs to be decreased the most in weight reduction diets. It still is necessary for the pet to receive some fat. Fat-soluble vitamins (vitamins A, D, E, and K), essential fatty acids, and other fats are necessary for health. It is generally recommended that the fat content of weight reduction foods for cats should be 7-14% of dry matter.
Fiber
A reducing diet generally has increased fiber which is an indigestible carbohydrate. High-fiber, low-fat diets allow a greater loss of body fat than simply feeding smaller amounts of a high-fat diet. Fiber stimulates chewing, increases the metabolic energy needed to digest the food, slows the rate of movement of food out of the stomach, helps to stabilize the blood glucose level, and improves the sensitivity of the body to insulin. As a result, some nutritionists feel it has a 'satiety effect' meaning the animal will feel 'full' for a longer period of time. Fiber may slightly decrease the digestibility of other nutrients in the diet. Many diet foods contain over 5% fiber on a dry matter basis. Some diets contain up to 12-30% fiber. Diets containing that quantity of fiber, however, can cause flatulence and will increase the quantity of feces produced.
Protein
A reducing diet must contain adequate amounts of protein to prevent loss of lean body mass (muscle) while the animal is losing weight. A reducing diet for cats should contain at least 35% crude protein on a dry matter basis.
Calories
To lose weight, animals must take in less calories than they use so that they start using their body fat to make up the difference. The number of calories used varies greatly according to the age, size, and activity of the animal. In general, reducing diets for cats should have less than 3.6 kcal of metabolizable energy (ME) per gram of dry matter.
Vitamins and Minerals
Good, balanced weight reduction diets have a proportional increase in vitamins and minerals relative to the energy content. In the past, pets on reducing diets often developed dry, flaky skin because there were less than adequate fatty acids included in the diet. The better diet foods now have added fatty acids, sometimes in the form of fish oil, to ensure animals are receiving the appropriate levels of these essential nutrients. To keep your cat's skin and coat healthy, it may still be necessary to supplement your pet with a fatty acid supplement such as Derm Caps or Drs. Foster and Smith Vitacaps. Depending on the amount and type of food you feed, a balanced vitamin-mineral supplement may also be recommended.
Feeding a weight reduction diet
Always consult your veterinarian before placing your cat on a weight reduction program. Overweight cats should not be allowed to lose weight too fast, or a serious liver disease called hepatic lipidosis can occur. All members of the household should understand and agree to follow the diet instructions. Feeding a weight reduction diet while still feeding treats is a recipe for failure. Feeding the pet before you cook your own meal and eat can assist in decreasing the amount of begging at the table. Feed the overweight cat in a separate area from where the other pets are fed and prevent her from eating the other pet's food. It is often helpful to feed 3 to 4 smaller meals of the diet rather than just one or two. Be sure fresh water is available at all times.
Summary
Weight reduction diets can be helpful tools in producing weight loss in overweight animals. In selecting a weight reduction diet, a nutrient analysis should be performed to ensure the animal will maintain adequate nutrition during the weight reduction process. Increasing exercise and eliminating treats need to go hand in hand with the reducing diet, if we are to achieve optimal results.
