Redefining Obesity in Veterinary Medicine: Making the Case for "Clinical Obesity"
In this issue, we explore why 'clinical obesity' is more than just a term—it's a critical tool for enhancing outcomes in our fight against pet obesity
The words we use in veterinary medicine matter, particularly when it comes to obesity.
What healthcare professionals say and how they say it influences the acceptance of preventive measures, diagnoses, therapeutic plans, and treatment adherence. Choose the right words and express them effectively, and patients benefit. Selecting the wrong words may risk patient outcomes and jeopardize client relationships.
The terms used to describe obesity in animals have the power to inspire change and promote health or fuel bias and stigma, causing patients to suffer. Offensive words such as “fat” and “obese” can serve to judge and blame, and substitutions such as “chonky” and “fluffy” diminish the severity of the health impacts caused by excess adiposity. The veterinary profession needs a better, scientifically valid vocabulary for more precise, empathetic, and effective communication about pet obesity.
Obesity Blame and Shame
"Obesity" is unique in that it carries emotional and societal connotations absent in most medical conditions. Many mistakenly believe that obesity results solely from a lack of willpower, intentional overeating, or under-exercising, and that it can be "cured" through self-discipline alone.
Weight gain is often unfairly viewed as a personal choice, with those affected seen as entirely to blame. In veterinary medicine, pet owners are frequently held solely accountable for their pet's body condition, and obesity is often framed as a failure to be a "good pet parent."
While these sentiments contain some truth, they fall far short of the full picture. The causes of obesity in both humans and animals are multifactorial, including genetics, hormonal imbalances, environmental endocrine disruptors, alterations in the microbiome, lifestyle choices, and more.
Like many other chronic diseases, obesity typically results from a combination of factors. Yet, we rarely blame a patient for developing cancer, kidney disease, or even arthritis. In fact, we often console those affected by these conditions with phrases like, "It's not your fault." So why don't we approach obesity with the same compassion and understanding?
Obesity is an active disease state that negatively impacts quality of life, reduces life expectancy, and causes or complicates nearly every other medical condition. It is also an emotionally charged issue, burdened by a significant stigma that often acts as a barrier to care. Few diseases so urgently demand our most compassionate and empathetic language..
Defining Obesity in Evidence-based Terms
For the past several years, I've been advocating for a revision in how we define obesity in animals. The term "obesity" has become polarizing, with its definition varying widely among veterinary professionals. Body condition scoring establishes adiposity, but adiposity alone does not complete a diagnosis.
Further complicating the issue is how the general public and media perceive obesity, as an undesirable aesthetic or lifestyle choice rather than a serious disease, particularly in companion animals. Terms like "chonky cats" and "greedy dogs" are often used to defuse emotional triggers and reduce blame. However, these expressions also trivialize the life-threatening complications of obesity.
Words matter, and that's where the term "clinical obesity" comes in.
Global Shift to “Clinical Obesity”
The Lancet Diabetes and Endocrinology Commission on Clinical Obesity published its findings in January 2025, shifting the conversation in human medicine toward "clinical obesity." The commission had announced more than a year earlier that new terminology was necessary, particularly in response to the global surge in GLP-1 medication use.
The authors aimed to provide a medically coherent framework for disease diagnosis and to settle the ongoing dispute over obesity as a disease. We're working on this for veterinary medicine.
It’s Time for “Clinical Obesity” in Veterinary Medicine
The Association for Pet Obesity Prevention (APOP) and the World Pet Obesity Association (WPOA) have advocated for the use of the term "clinical obesity" in veterinary medicine. Adoption has been uneven. Parts of organized veterinary medicine remain unconvinced that obesity in companion animals is a distinct disease, or that current language falls short. Some approaches continue to place responsibility primarily on owner behavior, despite evidence from human and pediatric medicine that this framing does not improve outcomes.
The goal of defining clinical obesity is to address the limitations of traditional definitions and diagnostic criteria that impede clinical practice and recommendation, ensuring that veterinary patients with obesity receive the care they deserve.
These diagnostic terms will become increasingly relevant as veterinary obesity treatments evolve. Therapeutic diets continue to become more sophisticated, and new supplements and techniques aid in preserving and promoting lean muscle mass. Over the next decade, obesity medications will likely be approved for companion animals, making evidence-based definitions and diagnoses essential for prescriptions. Improved obesity diagnosis utilizing artificial intelligence-assisted imaging, adipose-specific biomarkers, and emerging modalities will require us to consider defining obesity in animals beyond the charts.
Previous obesity classification schemes and nomenclature, such as "morbid obesity," "Stage 1 obesity," "metabolically healthy obesity (MHO)," or "medically unhealthy obesity (MUO)," fail to identify a clinical disease and are unwieldy. This is not to say they lack validity but rather that they have not gained widespread acceptance. Physicians have attempted similar approaches with similarly disappointing results. It's time to explore a new path forward.
Two Stages of Obesity
Obesity in dogs and cats is a condition of excess body fat, usually a body condition score of 8 to 9 on a 9-point scale. In the framework APOP and WPOA follow, it has two stages.
Preclinical obesity is obesity-range body condition with no health or functional problem linked to excess body fat after appropriate assessment. It is the risk stage. It is not a reason to wait. Treatment starts here.
Clinical obesity is obesity-range body condition plus a meaningful health or functional problem with a supported link to the excess body fat, confirmed by examination or diagnostic testing.
Diagnosis follows a three-part check, the Three A's. Adiposity: excess body fat is confirmed. Abnormality: a real problem is documented, such as impaired mobility, labored breathing, or an abnormal test result. Attribution: the problem is reasonably connected to the excess body fat after other explanations have been considered.
A high body condition score alone does not establish clinical obesity. A coexisting disease alone does not establish it either. Both findings must be present and the link between them must be supported.
Every stage is treated. The stage sets urgency, intensity, and what a clinician can justify prescribing. It never sets whether to treat.
As evidence for an obesity-first medical approach in human medicine continues to grow, these distinctions will become more consequential. Over time, we anticipate the development of more rigorous and sophisticated diagnostic algorithms and tools to support their use in veterinary medicine.
The Power of “Clinical”
In both human and veterinary medicine, the expectation is that introducing a new obesity term using "clinical" will help medical professionals and the general public recognize it as different, and as a disease.
As new obesity diagnostic capabilities and treatments become available, new language will be required. Veterinary medicine needs to learn from our human colleagues and begin transitioning to enhanced communication as new therapies and tests evolve.
By adding the modifier "clinical," healthcare professionals can also distinguish obesity from "fatness" and other stigmatizing terms.
"Clinical" implies the need for medical assistance and guidance. Clinical obesity signifies that a documented health or functional problem has been linked to the excess body fat.
A two-year-old Labrador Retriever at a body condition score of 9 with no identified adiposity-related abnormality has preclinical obesity. That is a real diagnosis with a real treatment plan, not an absence of one. What it is not is clinical obesity, because no documented problem has been attributed to the excess body fat. The distinction matters for what a clinician can justify prescribing. It does not determine whether the patient is treated.
The body mass index has similar limitations. It is a validated screening tool and useful in population analyses, but it is inappropriate as the sole basis for diagnosing obesity in an individual.
The Three A's complete the diagnosis by requiring a documented abnormality and a supported attribution alongside the adiposity finding. In the near future, I expect advanced diagnostic testing to facilitate earlier and more precise assessment.nostic testing to facilitate even earlier, more precise, and accurate diagnosis.
A New Era of Veterinary Clinical Obesity
The next decade will be an important time in the diagnosis and treatment of both human and animal obesity. Veterinary medicine has the opportunity to avoid many mistakes human obesity medicine has encountered over the past three decades, including those related to nomenclature and communication strategies. The Lancet Commission on Clinical Obesity worked with over 75 global organizations committed to redefining obesity medicine.
If you’re interested in helping us better understand and define veterinary clinical obesity, contact us. Together, we can promote better health and quality of life for our patients.