Obesity in dogs, Part 2: Treating excess weight with a multiple-modality approach

In Part 2 of our two-part discussion on overweight and obese dogs, we highlight modalities for treating the excess weight and monitoring the success of the various interventions. Effective management of excess weight in companion animals may include dietary, lifestyle, and pharmacologic modifications. Pairing interventions that benefit both the pet's and owners' health may be a valuable role for veterinarians.

DIETARY INTERVENTION

Establishing an appropriate dietary therapy regimen involves two important goals: The plan must be tailored to the individual animal, and caloric restriction must occur without concurrent protein starvation to prevent a loss of lean muscle tissue during weight loss.

Photo by Gregory Kindred

A weight-loss goal does not necessarily have to equate to the patient's achieving its ideal body weight.1 Indeed, the ultimate goal should be based on the pet, the family's situation and goals, and the entire family's—including the pet's—ability to reach the goal. It is important to set reasonable and attainable goals to avoid client discouragement, which may occur if the pet is not meeting the expected goal.2

Determining dietary intake

Calculate the current dietary intake, including all caloric sources, if possible.3 If this value can be determined, you could start a weight-loss program by recommending feeding the dog a total of 80% of the current energy intake. However, ideally—and certainly if the current intake cannot be determined because of ad libitum feeding, access to unmonitored feed sources, variable treat offers, or insufficient diet history—calculate the pet's maintenance energy requirement (MER) at the pet's target weight by using the equation3

MER (kcal) = 132 x body weight [kg]0.75

Estimations for energy restrictions are inexact. The dog could remain stable, lose weight, or even gain weight. Weight monitoring and intake adjustment will likely be needed, and the pet's family must be prepared for this long-term project.

Therapeutic diets

Veterinary therapeutic diets formulated for active weight loss are generally less energy dense than other diets are.4,5 The calories are diluted on a volume basis with fiber, water, or air, but these diets are not necessarily low in fat. Therapeutic diets vary widely in nutritional profiles, ingredients, and fiber concentrations, so appropriate options exist for a wide range of patients. Weight-loss diets are boosted with essential nutrients relative to calories so that when energy is restricted, protein, vitamins, and minerals are not restricted.

Feeding a maintenance diet for weight loss carries the risk of deficiency since these modifications have not been incorporated, and the diet will be fed for an extended period. That applies to situations in which owners are feeding restricted amounts of a maintenance diet only or attempting to dilute the calories of a maintenance diet with items such as green beans or pumpkin.

Recent evidence suggests high-protein diets facilitate the maintenance of lean body mass during weight loss and improve weight-loss success rates.6

Compliance tips

Providing measuring cups may help increase compliance. Using a portion of the diet for treats or training should also be suggested, as many owners do not realize that the entire diet does not need to be fed only from the bowl.7

Clients in the habit of giving treats will likely continue to do so with or without your endorsement. As such, an effective weight-loss program should include a treat allowance with daily guidelines and specific suggestions for treats. Up to 10% of the daily calories may be allotted for treats to avoid nutrient imbalances by dilution.8,9

Weight cycling

Dieting in people is often accompanied by repeated bouts of weight loss and regain, a phenomenon known as weight cycling or yo-yo dieting. Effects of weight cycling and obesity induction and reinduction in people and animal models have been reported.10-13 Recently, a prospective investigation of obesity induction and reinduction in nine beagles documented a significant increase of food efficiency in the obesity reinduction phase compared with the obesity induction phase—simply stated, the dogs became obese in a shorter time period at a lower calorie count (reinduction phase).14 These results demonstrated weight cycling in dogs in which rapid regain of body weight occurred after successful weight loss. These findings support the phenomenon of metabolic downregulation of energy needs with weight loss, which continues after target weights have been achieved.

PRESCRIBED EXERCISE

In addition to reducing an overweight pet's energy intake, by increasing energy expenditure through increased exercise, you will increase weight loss.15,16 A maximally effective weight-management program incorporates both calorie restriction and exercise recommendations.

Interactive exercise between dogs and owners is an alternative activity to enhance the human-animal bond, and increased activity could enhance weight loss in pets. Common examples of potentially appropriate exercises include low-impact walking, chasing a ball, tossing a Frisbee, swimming or using an underwater treadmill, and socializing at a dog park. Guided-exercise treatments with a certified canine rehabilitation practitioner following veterinary consultation may be beneficial in maximizing weight-loss goals.

In obese dogs, it is important to start an exercise program slowly and gradually increase the duration and intensity of the exercise. In some dogs, exercise may be impossible because of severe orthopedic or cardiopulmonary problems or because of the owners' inability to exercise with their pet.

The parallel problem of excess weight in pets and their owners represents a unique opportunity to target weight loss and increase activity in both groups. A comprehensive prospective study that is underway, Owners and Pets Exercising Together (OPET), uses the dog-owner relationship to affect the physical activity of both owner and animal (see the Related Link "Owners and Pets Exercising Together study" below).17

PHARMACOLOGIC INTERVENTION

Three pharmacologic approaches to weight management are available for people: drugs that reduce fat digestion from the intestine, drugs that reduce appetite, and drugs that increase metabolism. Of these three types of drugs, only orlistat (Xenical—Genentech) is approved for human consumption in the United States. Sibutramine (Meridia—Abbott Laboratories, Reductil—Abbott Laboratories) was withdrawn from the U.S. market by the Food and Drug Administration in October 2010. Orlistat is a derivative of a lipostatin that inhibits gastrointestinal lipases. In contrast to orlistat, sibutramine is a noradrenergic, serotonergic reuptake inhibitor that enhances both satiety and thermogenesis.

Photo by Gregory Kindred

Only one weight-loss drug is approved for administration in dogs in the United States. Dirlotapide (Slentrol—Pfizer Animal Health) is an intestinal microsomal triglyceride transfer protein inhibitor that prevents formation of chylomicrons in intestinal cells. This action results in an increase in peptide YY secretion. Peptide YY is a potent appetite suppressant that affects the satiety center in the hypothalamus and accounts for 90% of the drug action. The reduction of fat absorption in the small intestine due to the prevention of chylomicron formation is responsible for only a small fraction of the effect, and, thus, steatorrhea related to fat malabsorption is minimal.18-23

All pharmacologic weight-management aids should be considered short-term interventions, may have significant side effects, and may be contraindicated in some patients. Additionally, weight loss achieved by patients will most likely be temporary if owner behaviors are not concurrently modified to promote a more healthful lifestyle. For example, it is helpful to explain to owners that treats are similar to snacking between meals for people, and when giving treats is a well-established habit, it may require consciously and permanently adjusting what role treats play in the relationship (i.e. owners should consider bonding with their pets via a physical activity rather than through giving treats).

FOOD-RELATED ATTITUDES AND BEHAVIOR

Many dogs become overweight or obese because of the social bonding that occurs with owners and their dogs during feeding. This human-animal-bond activity adds a strong behavioral component to the development of obesity, which must be addressed. Food is such an important part of daily culture that it is critically important to recognize how owners view food and the importance of nurturance within their family system, recognizing that the family pet may become part of that culture.

To achieve success in changing food-related attitudes and behaviors, it is important to substitute low-calorie treats, games, or grooming activities for table scraps or other high-calorie treats. Begging for food is more of a behavioral problem than it is a hunger problem, and if this relationship is not considered in weight-loss programs, the program is doomed to fail. In some cases, consulting with a veterinary behaviorist is an important part of the overall plan for weight loss.

PATIENT MONITORING

Monitoring and adjusting are critical in any weight-loss plan. The dog should be weighed on the same scale every two to four weeks. A healthy weight-loss goal is a loss of 1% to 2% of body weight a week.24 A pet's family members must understand how long the weight-loss plan may take, and they should be encouraged to focus on the progress rather than on a quantitative end goal.24

At each weight assessment, evaluate compliance by reviewing the amount fed with the owners, including treats and unmonitored food sources. A dog that is losing weight too fast is at risk for losing lean body mass and for demonstrating undesirable behaviors. If the dog is losing too slowly, is stable, or is gaining, further calorie restriction may be indicated; however, concurrently, increased physical activity is likely preferable to reduce the degree of metabolic slowdown.8

Most evidence suggests that exercise improves the success rate of weight-loss programs.1,2,7,15-17,25 If possible, encouraging increased activity will facilitate more efficient weight loss and, once achieved, will help ensure maintenance of a lean body condition.

Adherence is crucial for the success of any weight-loss plan.8 A pet's family is responsible for feeding the correct amount of food and treats, weighing the pet regularly, following through on adjustments, exercising the pet, and controlling the dog's access to unmonitored food sources. The family must be committed to the weight-loss program for several months.

Consideration of concurrent diseases is also an important aspect of weight management. Indeed, many overweight companion animals must consume diets that may not be formulated for active weight loss. In these cases, it is advisable to consult with a veterinary nutritionist to ensure that appropriate and safe weight loss is possible.

CONCLUSION

Excess weight is the most common nutritional health problem in dogs, and obesity-associated risks continue to increase. Adipose tissue is a highly metabolically active endocrine organ, producing adipokines that are linked to inflammation and the inflammatory response. Thus, obesity is considered a chronic inflammatory disease, and many obesity-related risks may be attributed to this inflammatory state.

Obesity is treatable, and therapeutic options continue to increase. Additionally, a collaborative effort between owners and veterinarians is required to fully intervene in a sensitive and healthful manner and to monitor the situation when a companion animal needs to lose weight. Without this relationship, the meaning of food and feeding within the family system may potentially sabotage the intervention. But with an effective collaboration, the excess weight may be effectively addressed.

Editors' note: All of the authors of this article receive financial support from Waltham Pet Nutrition for a prospective human and canine obesity study entitled OPET: Owners and Pets Exercising Together.

Christopher G. Byers, DVM, DACVECC, DACVIM

VCA Veterinary Referral Associates

500 Perry Parkway

Gaithersburg, MD 20877

Cindy C. Wilson, PhD

Mark B. Stephens, MD, MS

Jeffrey Goodie, PhD, ABPP

Department of Family Medicine

School of Medicine Uniformed Services

University of the Health Sciences

Bethesda, MD 20814

F. Ellen Netting, PhD

School of Social Work

Virginia Commonwealth University

Richmond, VA 23284

Cara Olsen, PhD

Department of Preventive Medicine and Biometrics

School of Medicine Uniformed Services

University of the Health Sciences

Bethesda, MD 20814

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