Managing overweight pets successfully requires veterinary staff to go beyond standard nutrition and physical activity to include an understanding of the human–animal interaction. An effective weight loss plan incorporates calorie restriction, appropriate diet selection, physical activity, and discussion and modification of behaviours of the pet and pet's family. When prevention is not enough, this article will address how to approach weight management in overweight pets.
Introducing body condition scoring to pet owners
After determining a pet is any body condition score (BCS) above ideal, a discussion with the pet owner is the initial step to educate the family that their pet is overweight, and emphasise the health consequences of that excess weight (Figure 1). In multiple studies, 39% of owners underestimated their pet's BCS, even after knowing the BCS their veterinarian assigned to their pet (Rohlf et al, 2010; White et al, 2011). Furthermore, another study showed that half of the owners who correctly identified their pets’ BCS score above optimal still did not consider their pet to be overweight (Bland et al, 2009). Veterinary nurses should be prepared that pet owners may not know or understand what optimal weight is in their pets. Asking open-ended questions about their pet's weight may elicit information about pet owners’ perceptions of their pet's weight and their knowledge about the consequences. In one study on pet obesity (White et al, 2011), owners frequently used narratives or personal stories to explain their pet's weight status. When asked open-ended questions, the pet owners answered with historical information (pet was previously even more overweight, so the owner now feels their pet is thin in comparison), or they described personal or emotional rationale (acknowledging the pet was overweight, but felt guilty that their pet would resent them for withholding treats). Pet owners’ descriptions about their pet's weight and possible consequences of the excess weight will help gain the owner's perspective and potential challenges to discuss. Examples of open-ended questions to ask are included in Box 1.
Performing a nutritional assessment
Veterinary nurses should begin by assessing the pet, the family, and the environment, which includes a full diet history as described in the World Small Animal Nutritional Assessment Guidelines, available online at http://wsava.org/nutrition-toolkit (Freeman et al, 2011). All factors that impact feeding (current diet, daily schedule, specific treats, number and perceptions of household members), physical activity, and the environment (husbandry, environmental enrichment) should be identified. The veterinary staff can work together to perform a complete physical examination and any relevant diagnostic testing to determine if there are any medical conditions that may affect the weight management plan. As a part of every physical examination, the pet's current bodyweight, BCS, and muscle condition score (MCS) should be evaluated and recorded (Figure 2), which will help in monitoring the plan on follow-up appointments. Also, the pet owner's readiness to change, described in detail elsewhere (Churchill, 2010), should be assessed. This will help to identify potential opportunities and challenges when altering the pet's management and family dynamics. Tailoring the plan to the individual pet and family increases adherence and advances successful weight management (Brooks et al, 2014). For example, ‘non-negotiables’ — the food items that the pet owner will give regardless of the recommended treatment — can be an incorporated into management if asked about and discussed. Such compromises can help to increase adherence and trust in the future with the weight loss programme.
Selecting a diet
In the author's experience, over-the-counter diets marketed for weight management can be confusing for pet owners, as these diets vary considerably in calorie density (e.g. from 217–480 kcal/cup for dry cat and dog food) and feeding directions (Linder and Freeman, 2010). Additionally, restricting amounts of over-the-counter maintenance diets, including those marketed for weight management, could lead to deficiency of one or more essential nutrients (Linder et al, 2012). Nutrient profiles for weight loss diets should be chosen based on a pet's individual medical needs as well as the preferences and lifestyle of the owner and the pet (Box 2).
Adherence is critical in successful weight loss, so paying particular attention to owners’ concerns in diet selection will improve management. In general, weight loss diets should contain a high nutrient density (high nutrient:calorie ratio) to meet the essential nutrient needs of pets while reducing calories. In particular, increased protein is an important nutrient in weight loss diets, as it has been shown to help retain lean body mass during weight loss (Laflamme and Hannah, 2005). The optimal amount is unknown; however, diets that provide daily 4.96 g protein/bodyweight (kg)0.67 in cats or daily 3.28 g protein/bodyweight (kg)0.75 in dogs will meet National Research Council recommended allowances for otherwise healthy pets (National Research Council, 2006). Satiety can be an important aspect of weight loss as this may affect adherence to the weight management plan. Studies have shown that, in some pets, increased moisture or fibre leads to increased satiety (Jewell et al, 2000; Weber et al, 2007, Wei et al, 2011), though it is likely individual for each pet. Carnitine is sometimes added to diets for its role in fat metabolism, as well as omega-3 fatty acids for their role in decreasing inflammation. However, more studies are needed before widespread use is recommended. Reserving 10% of the total calorie intake for treats may also increase adherence without unbalancing the diet for pets (Box 3).
Additionally, a portion of the dry kibble can be reserved from the daily allowance to increase their pet's ‘treat’ allowance, and some low-calorie (2–3 kcal/treat) commercial treat options are also available.
Determining energy requirements
Starting points for caloric restriction in weight loss studies vary (Toll et al, 2010). In an ideal situation, a 20% restriction from the current intake can be a starting point if the current calorie intake can be obtained or estimated from a complete diet history (Burkholder and Bauer, 1998). However, if this is not known, recommended starting points can vary including equations for resting energy requirement (RER = 70 kcal/kg0.75) for current or ideal weight as well as a percentage of the maintenance energy requirement (MER) for current or ideal weight (Toll et al, 2010). In the author's experience, the calculated RER for estimated ideal weight can be a starting point from which adjustments can be made accordingly.
More important than the starting caloric amount are weekly or biweekly weigh-ins to ensure a safe and effective rate of weight loss.
Adjusting the optimal rate of weight loss
The aim of calorie restriction is to ensure that the rate of weight loss is steady, but the optimal rate of weight loss is likely dependent on each pet. Published rates of weight loss range from 0.5–2% per week of bodyweight loss for cats and dogs (Laflamme and Kuhlman, 1997; Burkholder and Bauer, 1998). In the author's clinical experience and one study, a rate of 1% of bodyweight loss per week limited risk of nutrient deficiency, loss of lean body mass, and rebound weight gain (Laflamme and Hannah, 2005). If pets have additional medical concerns, an even more gradual rate of weight loss (0.5% of bodyweight per week) is recommended, though more studies are needed to determine exact rates in specific disease states. Finally, owners should be prepared that the majority of dogs and cats will need lifelong calorie restriction for long-term maintenance of ideal weight.
Physical activity
The veterinary nurse should determine whether a patient is suitable for physical activity (Figure 1), and discuss with the pet owner how exercise may be integrated into a comprehensive weight management plan for their pet. Though more studies are needed to determine optimal amount, duration, and intensity of physical activity in cats and dogs, any increase in physical activity is likely beneficial for a pet of any weight. Encourage owners to increase their pet's activity gradually based on their needs, starting with 5–10 minutes per day with creative and low-intensity activities for sedentary pets (such as walking or swimming). Creativity in activities, such as incorporating food dispensing toys, spreading meals throughout different parts of the house, interactive toys, laser pointers, and electronic mice can also be helpful.
Monitoring and follow up
Regardless of the initial calorie allocation and diet selected, effective follow up and ongoing monitoring by the entire veterinary team is critical to success. Following the initial appointment, after 1–2 weeks on the plan, discuss any potential concerns with pet owners to identify any challenges or need for adjustment of the plan. Follow up every 2 weeks until the desired rate of weight loss is achieved; the frequency of follow-up appointments can be decreased as necessary. Providing positive support for pet owners will increase adherence and reinforce the effort of the pet owners. Monitoring and follow up can be challenging, and a list of common challenges and suggestions for overcoming them are available within the 2014 AAHA Weight Management Guidelines (Brooks et al, 2014), available online at: https://www.aahanet.org/PublicDocuments/Weight_Management_Guidelines.pdf.
Psychology of obesity
In addition to standard nutritional and exercise programmes, it is critical to understand how the dynamics of human–animal relationships can impact the prevention and treatment of obesity. Understanding weight loss in the broader context of human–animal relationships allows veterinary staff to effectively develop and support successful treatment plans. Strong attachment to pets may impact what pets owners are willing to do, influencing treatment both positively and negatively. For example, a highly attached pet owner may be more willing to devote financial resources and time; however, strong attachment may limit pet owners in withholding food or treats that may represent a part of that relationship. For overweight pets, compromising the type of treats or substitution of activities that foster that attachment can preserve the relationship while adhering to a weight management plan.
Conclusion
Obesity is a multifactorial condition that needs to be treated as a complex nutritional disorder. Despite standard diet and exercise, many weight management plans fail if the complex nature of obesity is not acknowledged and addressed. Comprehensive weight management programmes include pet and owner assessment, proper diet selection, caloric restriction, physical activity, and modification of pet and owner behaviour that preserves the emotional bond between pet owners and their pets. Obesity requires lifelong management; however, when veterinary staff go beyond standard treatment to include an understanding of human–animal interaction, it can also be completely preventable and curable.