From fat to fit-Avoiding six common mistakes while helping pets combat obesity (Sponsored by Nestlé Purina)

We veterinarians are all aware that weight problems affect 30% to 40% of our patients. The effects of obesity are far-reaching, predisposing our patients to insulin resistance, type II diabetes, orthopedic disease, and possibly even cancer.1-3 We all know that a pet is not in ideal health if it is not at its ideal weight, but many of us have also discovered how difficult it can be to motivate clients to help their pets lose weight. In this article, I will describe six common mistakes veterinarians make when implementing weight-management programs and explain how best to avoid them.

Mistake #1 — Not backing your recommendations with hard science

To drive home the importance of weight loss to my clients, I now discuss the ramifications of obesity and chronic inflammation on the pet's body. Although this does not motivate every client to be more interested in his dog's or cat's body condition, it may persuade those owners who are on the fence to try a weight-loss program.

The pathophysiology of obesity is becoming much clearer. Fat is now recognized as an endocrine organ, since adipose tissue releases local and systemic cytokines (known as adipokines) that are thought to regulate systemic inflammation and food intake.1 A handful of measurable mediators of chronic inflammation and adipokines have been defined in dogs and cats.1 The picture of obesity and chronic inflammation in pets is similar to the evolving human story. When fat from obese animals is examined histologically, apoptotic/necrotic adipocytes are surrounded by inflammatory macrophages. This results in a chronic inflammatory response. This process may stimulate further release of inflammatory mediators from surrounding adipocytes, creating a chronic inflammatory stimulus back and forth between macrophages and adipocytes.

There are 40 to 50 identified adipokines released from fat cells. The ones of clinical importance in dogs and cats are adiponectin, leptin, monocyte chemotactic protein-1, and resistin. Adiponectin is the most abundant adipokine in the bloodstream in all species, but it does not circulate as a single monomer only. It circulates and has its best insulin-propagating activity as large polymers of six to 18 bonded monomers. In this form, it is called high-molecular-weight (HMW) adiponectin.4 HMW adiponectin is released from adipocytes in lean people and its secretion is severely diminished in obese people, with post-gastric-bypass surgery patients showing increases in serum HMW adiponectin.5 This is important because adiponectin improves insulin signaling; therefore, when obese animals stop secreting it, insulin resistance can ensue.

Recent results from our data set and now from an Australian group suggest that adiponectin and HMW adiponectin concentrations are not affected during weight loss in dogs.6,7 However, even in obese dogs, it appears that adiponectin is continually secreted at high concentrations into the blood. Could this be part of the reason why insulin resistance in dogs is hard to define in clinical investigations? And is this why type II diabetes is rarely observed in dogs? Further research is needed to elucidate the clinical ramifications of adiponectin secretion in dogs and cats.

Figure I

Table 1 shows results from a recent study examining adipokine concentrations before and after a weight-loss program in dogs. The results show that all of the aforementioned adipokines except for adiponectin decrease after about 25% weight loss in a group of dogs, similar to other reports.8,9 This decrease in inflammatory adipokines corresponds with a drop in the systemic marker of inflammation, the acute phase protein called C-reactive protein (CRP). In obese people, the increased inflammation is associated with an increased risk of heart disease and type II diabetes.10 The chronic health ramifications of this slightly elevated inflammatory response in dogs and cats still need to be investigated.

Although there is much left to be studied, we do know that obesity has a multitude of systemic effects and predisposes pets to many problems. We can do a better job of communicating to clients what is definitively known about the short- and long-term health risks of obesity in pets.

Mistake #2 — Having a "do as I say, not as I do" attitude

One of the biggest problems in practice is that we do not invest adequate time in obesity prevention or management. We ask clients to exert a great deal of effort for the health of their pets, and so we should be willing to do the same. Fortunately, the major pet food companies make software that allows us to track our patients' progress. This tracking can be entrusted to a technician who is familiar with your weight-loss software program. When you dispense the first bag of a therapeutic diet, it is best to have your technician schedule several monthly weigh-in sessions for the animal. These are usually free office visits, but you will find that the client typically buys another bag of food or another item, such as a flea control product or heartworm preventive, which more than justifies the time spent in these cases. Reminder calls before each weigh-in session are a good idea. Time and time again, plans without weigh-in appointments fail because of client noncompliance. If veterinary professionals do not take a long-term interest in these cases, then clients are also less likely to comply or come back for that second bag of weight-loss-formula food, and the battle is lost.

Mistake #3 — Miscalculating the pet's maintenance energy requirement

Often the first mistake that veterinarians make when implementing a weight-loss program is incorrectly calculating a patient's maintenance energy requirement (MER). For animals weighing less than 30 kg, the MER is calculated in kilocalories (kcal) by first using the linear equation to calculate the resting energy requirement (RER):11

RERkcal = 30(BWkg) + 70.

Then, to determine the MER, a multiplier is applied to the RER. This multiplier is based on the animal's activity level, and it is frequently around 1.5. With this equation, you should use the pet's ideal body weight. Other weight-loss equations use current body weight and/or body condition score to calculate the daily caloric amount. For more information on one such method, visit Purinaveterinarydiets.com, or call the Veterinary Resource Center at 1-800-222-VETS (8387). Regardless of the methods used, it is ideal to target between 1-3% weekly weight loss for dogs and between 0.5-2.0% in cats.

One common mistake in using this equation is calculating the RER using the animal's current body weight instead of its ideal or goal body weight. You should use the pet's ideal body weight.

A second error can occur with the activity level multiplier. Using 1.5 as the multiplier is acceptable for young active dogs or indoor/outdoor cats, but it is not appropriate for inactive dogs or indoor cats. Often the multiplier should be less than 1.5, particularly in cases in which a previous weight-loss program was unsuccessful. Recent research suggests that obese, inactive cats should start at their RER (that is, with a multiplier of 1.0), because they are not active enough to have an MER. The multiplier should be closer to 1.0 or 1.2 in the typical inactive, neutered, overweight dog.12,13

Unfortunately, the linear RER equation only works for dogs that weigh less than 30 kg. If used for an obese 50-kg Rottweiler, then the dog's kilocalorie needs would be overestimated right from the start. For larger dogs, the RER is calculated by plugging the ideal body weight into this exponential equation:13-15 95(BWkg)0.75 . Be sure you begin a patient's weight-loss program based on correct calculations. Use the pet's ideal body weight in your RER calculations and be sure to use an appropriate multiplier to calculate a pet's MER.

Mistake #4 — Not addressing the pet's activity level

The issue of activity level in weight-loss programs for cats and dogs has been hotly debated. I recently completed a study using pedometer technology with dogs and found a very strong correlation between body condition score (BCS) and average daily number of steps (Figure 1).16 This suggests either that obese dogs walk less than thinner dogs or that walking less predisposes dogs to obesity. A second clinical study recently conducted by my laboratory group suggests that the former is true.6 In the second study, we also measured steps taken with a pedometer during a weight- loss program, and we found that pedometer readings were virtually unchanged when the dogs' average BCS dropped from 8 to 5.5. That is, weight loss did not increase their activity level.

Table 1. Medians for body weight, body condition score, serum adipokines, and markers of inflammation before and after weight loss

This, unfortunately, really points the finger at owners. From our data, we predict that the owner's activity and willingness to increase the dog's physical activity may play a role in the success of a canine weight-loss program.

Another question is whether active dogs lose weight quicker than less active dogs do. Our study showed that active dogs could eat approximately 5 more kcal/kg of metabolic body weight (not kg of true body weight) during weight loss. Thus, activity does play a role in calorie consumption and weight loss. In our study, active dogs averaged about 5,000 more steps per day than inactive dogs did. This equates to about a 2-mile walk each day.6

It is, without a doubt, more challenging to increase the activity level of cats, especially obese cats. Veterinarians should encourage owners to work at this, and share their own ideas about ways to boost the cat's activity level in the home. Although most cats quickly grow bored with the same activities, if owners are willing to be creative, they can pique a cat's interest by rotating toys or using laser pointers and treat dispensers.

Mistake #5 — Not addressing problems with the pet's behavior and satiety

Undesirable behaviors, such as begging, breaking into pet food bags, and food protectiveness, can develop or worsen during a weight-loss program. Owners are less likely to comply with your recommendations if they see these negative behaviors develop or worsen.

Because of my involvement with a fairly extensive obesity trial and routine obesity clinic work, I feel that switching some pets to a canned therapeutic food or a combination of canned and dry foods can sometimes result in progress. An 8-oz portion of dry kibble has between 225 and 275 kcal for dogs and a half cup of food (4 oz) has 125 to 175 kcal for cats, while a 13-oz can for dogs has 175 to 275 kcal and a 6-oz can for cats has 110 to 130 kcal. Therefore, the cans contain fewer calories but more volume. Clients will appreciate being able to feed the increased quantity, and the canned food is likely to provide more immediate gastric fill, increasing the dog's or cat's satiety.

Another trick for adding volume to a dog's diet is to substitute green beans for dog food. We have gone as high as 1 cup of green beans per cup of dog food. The owners appreciate the extra volume given, which creates the needed gastric fill.

When it comes to cats, portion control becomes an issue since every owner's 1/4-cup can be different. Ask cat owners to use a kitchen scale so they can precisely measure grams of food per feeding. Another trick with cats is to use zucchini to create gastric fill. Cats do not usually appreciate vegetables, but some seem to enjoy the texture of firm, steamed zucchini. Instruct the client to start adding three or four cubes of chopped, steamed zucchini to the regular meal. In some of our cases, cats ate up to 50 g of zucchini each day, and owners claimed that begging behaviors were diminished.

Mistake #6 — Using the wrong food

When choosing a food for a weight-loss program, you need to choose what is optimal for the patient. If you use a "light" food and restrict the assumed calories to around 60% of the MER at ideal body condition, you can create a subclinical nutrient deficiency since these foods are not designed for calorie restriction.17 Many companies provide around two times the Association of American Feed Control Officials (AAFCO) requirement when adding vitamin and mineral premixes during manufacturing, but some companies stay close to the AAFCO requirements, so there could be subpar vitamin and mineral consumption when the total amount of food is restricted. Therefore, when clients ask to use an over-the-counter light food, I often supplement the dog food with a human complete multivitamin (one-half tablet per 25 kg body weight for dogs). I do not recommend doing this for cats.

A bigger problem with using an over-the-counter light food is the fact that the calorie content of that product is really not known, since most of the caloric information is based on calculations of the guaranteed analysis numbers from the package rather than actual analysis of the food. Also, if the food is higher quality and more digestible than what AAFCO assumes for their calculations then the calculations may also be flawed and can contain more calories in the food than shown on the label. Additionally, the manufacturer's calculations are done based on the guaranteed analysis label, which contains minimum protein and minimum fat information. Thus, a food that is labeled as containing 5% fat may really contain 7% fat, meaning that it may contain 10% to 15% more calories than the amount calculated by the manufacturer. This is partly why manufacturers hesitate to label pet foods with kcal per cup or per can, since it is probably a low estimate of the true calories in the food.

An emerging area of interest in the therapeutic pet food market is the addition of isoflavones and other flavonoid supplements to foods. There is some indication that these bioactive molecules can diminish food intake. The exact mechanism of action has yet to be determined, but it is currently thought that flavonoids may act at the level of the hypothalamus to hinder appetite. The most convincing evidence has been in cats, though the long-term effects seem to be less rewarding.18-20 The flavonoids may only be useful for temporarily decreasing appetite. One study showed that eating behaviors returned to normal within a week.20 In the same study, the use of the isoflavone genistein enhanced retention of lean body mass during weight loss, which is intriguing. From a theoretical standpoint, maintaining lean body mass is advantageous since it is more metabolically active and, therefore, helps to burn fat during weight loss.

To preserve lean body mass during weight loss, two approaches have been used successfully. Fortifying food with 150 mg to 500 mg carnitine can improve retention of lean mass during a weight-reduction protocol.21 Other evidence suggests that a high-protein diet (40% to 50% dry matter) can help retain lean body mass during weight loss.22 Lean body mass retention cannot be achieved by feeding common over-the-counter light foods, which are often moderate to low in protein and are usually not fortified with carnitine.

Conclusion

As a profession we are on the cusp of new and exciting product innovations that will help our patients combat obesity not only with greater success, but also in a healthier way. The adage that "calories in must equal calories out" is still the key to successful weight loss. But we veterinarians can help ensure the success of our patients' weight-loss programs by avoiding the six common mistakes reviewed in this article. In summary, we should back up our recommendations for a weight-loss program with the science at hand, devote adequate time to obesity prevention and management in our practice, ensure the accuracy of the initial calculations on which our caloric recommendations are based, take into account the activity level of our patients, acknowledge that we may need to alter feeding recommendations for some pets to sate them and prevent negative behaviors, and help clients choose the best food for a patient's weight-loss program.

References

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