3 Nov 2015
Cecilia Villaverde
Job Title
Obesity is a common condition in dogs and cats with prevalence ranging from 25% to more than 50% in western Europe and the US.
It is not only a risk factor for many diseases, but it can also worsen clinical signs of others. Moreover, in dogs, being overweight can shorten lifespan, but despite increasing awareness, the overall prevalence of this problem has not decreased, which means there is a lot to do by the veterinary team regarding both prevention and treatment of this condition.
Several studies have shown it is common for owners of overweight pets to be unaware of the problem. Thus, performing a nutritional evaluation on each visit and communicating the results to the owner is critical to ensure the family of the pet knows of the problem and can decide to act on it.
WSAVA has published nutritional guidelines1 to help veterinarians adequately perform this nutritional evaluation.
Owners also need to be aware obesity is not a cosmetic problem: being overweight is linked to several diseases (either by contributing to their aetiology or by worsening clinical signs) and to a decreased longevity in dogs.
Findings from the signalment, history and physical exam (such as age, presence and severity of comorbidities) will affect if, how, and when the veterinary team addresses obesity. In patients with severe comorbidities, these will take priority over obesity unless being overweight has a significant impact on quality of life. However, in all other cases, overweight patients should be treated to avoid the negative health effects of excess body fat.
In my experience, communicating the health risks, using visual tools, and discussing obesity as a medical condition (rather than blaming owners for overfeeding the pet) is very useful to broach the subject delicately.
We must identify overweight pets in order to treat them. The most common diagnostic tool is the body condition score (BCS) scale (Figure 1). The BCS uses visual and tactile clues to assess fat depots and give a score to the patient. We can show this visually to the owner using the WSAVA toolkit2, which uses the nine-point scale.
Each point above five represents a 10% to 15% excess bodyweight and thus the BCS scale can be used to back calculate an ideal bodyweight, if one is not available from the weight history of the pet. For example, a 40kg dog with a BCS of 8/9 is three points above ideal, thus, has an estimate excess weight of 30% to 45% (12kg to 18 kg) and an estimated ideal weight of 22kg to 28kg. Some companies offer this BCS as a sliding scale on their websites to help owners for both dogs3,4 and cats5,6. There are websites such as PetMD7 that offer this as well.
There are other BCS scales (like the five-point scale and one based on shape8 and even other visual diagnostic tools, such as the body fat index (BFI), can be found9. The BFI also uses visual and tactile clues, but has a wider scale and it expresses the results in a similar way to the body mass index (BMI) used in human medicine, with the goal of helping the owner understand his or her pet’s problem.
There are also morphometric measures that relate bodyweight to body size and shape and can help diagnose obesity; one pet food company provides this tool9 where the veterinarian enters the different measures of the pet and a diagnostic of obesity plus a “target” ideal bodyweight is provided. The tool is also available as an app10,11.
Once the owners are aware of their pet’s issue and are onboard for treatment, the goal is to increase energy expenditure through physical activity, if possible, and to decrease energy intake. The latter, called energy (or calorie) restriction is the cornerstone of obesity management. Clinicians have to estimate current energy requirements via a detailed diet history and then apply a 20% to 30% restriction.
If this is not possible, for example in pets fed at will or in multi-pet households, we estimate current energy requirements with formulas and apply the restriction to that value, while considering the formulas have an associated error of 50% and initial estimations can thus be off the mark. The author uses the resting energy requirement (RER) formula for dogs and 0.8 × RER for cats (RER being 70 × bodyweight [kg]0.75 Kcal/day). These formulas can be used with current or ideal bodyweight depending on the specific situation, the latter being a more aggressive approach. There is a useful app available to calculate energy requirements12.
These or any other formulas are all valid as a starting point, but all of them will need frequent readjusting. If treats are allowed, maximum 10% of the daily calories can be allowed for them, with 90% of the calories then used for the therapeutic weight loss diet.
Veterinarians should use specific veterinary therapeutic diets for weight loss whenever possible. Not only do they provide less Kcal/kg, allowing owners to feed more volume of food than when using a maintenance diet, but they also provide nutrient fortification. Using these diets allows for calorie restriction without simultaneously restricting nutrients. This is especially important regarding protein, because a marginal protein intake will promote lean body mass loss, which opposes weight loss and promotes weight regain.
This is the most important step, especially when estimating energy requirements using a formula rather than current energy intake. Initially, the veterinary team should check bodyweight and BCS every two weeks, until the desired rate of weight loss (1% to 2% bodyweight loss per week) is achieved, when controls can be done every four weeks. If the owner has a good scale at home, controls can be done remotely by telephone or email, although clinic visits allow for reinforcement of recommendations, provision of food, and provision of encouragement and reassurance.
Pet owners can sometimes feel they are “starving” their pet and making them unhappy, and it is important to keep them focused on all the positive aspects of the desired outcome. Visual tools, such as plotting weight evolution over time on a spreadsheet, will help keep owners focused on the long-term success of the plan.
The vet team can also use social media to encourage compliance and perseverance, posting before and after pictures or even organising contests among the clients. Getting owners of pets on weight loss plans together in social media or during follow -up visits can also help owners support each other and offer tips and encouragement.
Figure 2 shows the algorithm to follow regarding adjustments during checkup appointments.
We should always discuss obesity prevention and treatment in healthy pets coming to us for wellness visits. Puppy and kitten “starter” kits should include information regarding obesity prevention and list the risk factors for this condition: age, breed, sedentarism and, most importantly, sterilisation. Showing the owners of a new puppy or kitten what their pet should look like and teaching them to give a BCS to their pets is essential. Also helpful is to give a specific written dietary recommendation (name of diet, amount to feed, method) at each visit, independently of the reason for presentation.
Major pet food companies have reliable information regarding weight management. Also, owners can keep a food diary either during the weight loss plan or as a prevention measure to accurately calculate daily calorie intake13,14.
There is an app for pet owners that can help them achieve success in the weight loss plan15.
Addressing obesity in pets is both good medicine and good business. The best proactive way to address this problem consists of informing owners about healthy weight and BCS during puppy and kitten wellness visits and at the time of sterilisation. There are a variety of easily accessible tools to help both the veterinary team and the pet owner to achieve and maintain successful weight loss.
