Global Pet Obesity Initiative

We call for the veterinary profession to adopt uniform nomenclature for canine and feline obesity.

Currently, there is no universally accepted definition of obesity in dogs and cats. This lack of professional consensus has created confusion among veterinary professionals, industry stakeholders, and pet owners. It also makes it challenging for veterinarians to provide clear, consistent messages to clients about obesity and may help explain why the condition is rarely recorded in patients’ clinical records.¹

We believe that adopting and widely publicizing a standard definition of obesity will raise awareness of the disease and increase discussion and motivation to act within the profession, with the ultimate goal of improving the health of cats and dogs.

Our recommendation is that obesity be defined as body weight 30% or more above ideal weight. While excess body weight (overweight and obesity) represents a continuum and any cut-off point for the onset of disease is somewhat arbitrary, this definition correlates with human obesity standards such as body mass index (BMI) and abdominal circumference.² It is also consistent with, and broadly supported by, veterinary studies demonstrating associations between obesity and comorbid diseases,³⁻⁵ functional impairment,⁶⁻¹¹ and decreased quality of life.¹² ¹³

The most practical clinical tool for measuring adiposity is the Body Condition Score (BCS). A 30% increase above ideal body weight corresponds to a score of 8/9 on the preferred 9-point BCS system.¹⁴⁻¹⁷ However, defining obesity based on percentage above ideal weight, rather than BCS alone, is preferable because it enables veterinarians to precisely identify the onset of obesity using multiple strategies.

For example, if a veterinary practice recommends routine body weight and BCS assessments throughout a pet’s life, and formally records the healthy adult weight of a dog or cat (i.e., the weight at early adulthood when BCS is ideal),¹⁸ subsequent weight gain can be tracked accurately as a percentage change from the healthy adult weight. This approach provides a more precise determination of when obesity begins, improving early detection and intervention.

We urge the global veterinary community to adopt a universal Body Condition Score for dogs and cats of whole-integer, one-through-nine (1–9) scale. Many different body condition scoring systems have been suggested for estimating the adiposity of dogs and cats3,4,14-17,19-22 and, while they may be broadly comparable (for example a 5-unit system using half units is broadly equivalent to a 9-unit system), having different methods creates confusion. Not only is this problematic for veterinary professionals and owners when discussing obesity and health care recommendations, it can also lead to inconsistency in interpreting the results of scientific studies. In adopting a universal system, we believe that the 9-unit body condition score is preferable. This system has been more extensively validated than other systems, for example by comparing scores against precise measures of body fat mass using dual-energy X-ray absorptiometry, DEXA).14-17,22 It is also the system that has been recommended by the WSAVA Global Nutrition Panel.23 We recognize that other validated methods of determining adiposity have been developed for cats and dogs, such as using multiple zoometric measures.20,21 While we would not discourage their use, we believe that body condition scoring has many advantages most notably speed and simplicity, to ensure consistent use in veterinary practices. By adopting a universal BCS, we believe veterinary teams will be better able to interpret veterinary medical research, more consistently and accurately assess their patients’ body condition, and clearly communicate with colleagues and clients.

We call on the veterinary profession to formally recognize canine and feline obesity as a disease.

For years, the human medical field has debated whether obesity should be classified as a disease.²⁴⁻²⁸ Opponents argue that body fat accumulation is simply a normal physiological response to an abnormal, “obesogenic” environment.²⁷⁻²⁸ However, obesity follows a disease-like progression: one or more causal factors trigger physiological changes that ultimately result in functional impairment and health decline.²⁶

In animals, prolonged positive energy balance causes the expansion of adipose tissue and fat deposition in other organs. This process disrupts metabolic, hormonal, and inflammatory pathways, leading to comorbidities and decreased quality of life.

Obesity meets the American Medical Association (AMA) criteria for defining a disease:

1. Impairment of normal body function

2. Characteristic signs or symptoms

3. Associated harm or morbidity

Some critics argue that labeling obesity a disease could negatively affect well-being or fail to improve medical support.²⁷⁻²⁸ However, studies show that a formal disease classification can reduce stigma, encourage proactive treatment, and improve access to care.²⁵⁻²⁶ The AMA adopted this position in 2013,²⁵ and many major organizations—including the World Health Organization, World Obesity Federation, FDA, and NIH—now support it as well.²⁶,³⁰⁻³¹

The Global Impact of Pet Obesity

Obesity is one of the most common medical disorders in veterinary practice.³⁻⁵,³²⁻³⁴ Studies suggest that over half of dogs and cats are overweight or obese, with prevalence rising worldwide, including in developing countries.³⁵⁻³⁶ Of particular concern, approximately 21% of dogs are already overweight by six months of age.³⁷

Obesity has serious consequences:

• Reduced life expectancy³⁸

• Lower quality of life¹²⁻¹³

• Increased risk of comorbidities³⁻⁴

• Metabolic, cardiovascular, respiratory, and renal dysfunction⁹⁻¹¹,³⁹

• Significant financial burden for pet owners⁴⁰

Companion animals differ from humans in one crucial way: they cannot make diet or feeding decisions for themselves. This underscores the responsibility of veterinarians and pet owners to intervene. Recognizing obesity as a disease will compel action, encourage innovation, and drive the development of new solutions for prevention and treatment.

While some argue that diagnostic tools such as BMI in humans or BCS in animals are imprecise,²⁷ this does not invalidate disease classification. Many chronic conditions—such as chronic kidney disease or periodontal disease—use diagnostic staging systems despite similar variability.⁴²⁻⁴³

Just as these systems are accepted, so too should obesity be recognized as a disease. This classification is consistent with veterinary practice and supported by a growing body of global research and consensus, including recommendations from the WSAVA One Health Committee.⁴¹

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