2021 AAHA Nutrition and Weight Management Guidelines

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The guidelines discuss the components of a systematic approach to nutritional management of dogs and cats. A nutritional assessment, including a body condition score and muscle condition score, is a screening evaluation that should ideally be performed at every examination. Individualized nutritional recommendations, based on the nutritional assessment, should be designed to achieve and maintain an appropriate body weight and meet nutritional requirements. Communicating nutritional recommendations to clients is a challenging aspect of nutritional management because pet owners may interpret the practice team’s guidance as advocacy for a particular pet food brand or a judgment of the client’s ability to properly care for the pet or of the owner’s own nutritional status. The guidelines discuss approaches for effective, nonjudgmental communication of dietary recommendations to clients and strategies to increase acceptance of and adherence to veterinary nutrition recommendations. Other pet nutrition topics of current interest include recommendations for particular pet life stages, breeds, and disease conditions; risk factors for nutritional deficiencies and obesity; and considerations for home-prepared diets. (J Am Anim Hosp Assoc 2021; 57:153–178. DOI 10.5326/JAAHA-MS-7232)


Nutritional management is a central component of a complete healthcare plan for canine and feline patients and is integral to a pet’s longevity and quality of life. The positive impact of proper nutrition on health and morbidities such as chronic kidney disease (CKD), diabetes mellitus, and osteoarthritis is well accepted. Thus, a nutritional assessment of canine and feline patients should be performed on a regular basis throughout all pet life stages, ideally at each exam visit. With that goal in mind, the objectives of these guidelines are to:

  • Describe how to perform an individualized, breed-specific, evidence-guided nutritional assessment for canine and feline patients.
  • Provide recommendations for diagnosis, treatment, and management of under- or overweight pets.
  • Provide a comprehensive list of nutrients of concern for specific health conditions.
  • Offer suggestions on how to effectively communicate and educate owners about nutritional recommendations, including for weight control.
  • Provide strategies to increase adherence to pet nutrition recommendations.
  • Address several nutrition-related topics of current interest, including raw and home-prepared diets, breed-specific nutrition, and diet-associated dilated cardiomyopathy in dogs.

This report updates and complements previously published but still relevant nutrition-related guidelines produced by the American Animal Hospital Association. These include the 2010 AAHA Nutritional Assessment Guidelines for Dogs and Cats and the 2014 AAHA Weight Management Guidelines for Dogs and Cats.1,2 These prior guidelines address two essential components of nutritional management: assessment and weight control. The 2021 AAHA Nutrition and Weight Management Guidelines for Dogs and Cats include other important topics necessary for a truly comprehensive approach to dietary management in primary-care companion-animal practice. These include step-by-step methods for performing a complete nutritional assessment and preparing an individualized nutritional plan as well as communication tips that promote optimal adherence to the dietary recommendations.

Practitioners have minimal or no control over certain aspects of pet health such as the patient’s genetics and home environment. Nutrition, on the other hand, can be substantially influenced by the veterinarian’s medical expertise and recommendations. Achieving this positive effect requires a partnership between the veterinarian, the practice team, and the pet-owner client. More so than many other pet healthcare topics, discussing nutrition with clients can include sensitive topics such as obesity, pet food choice, feeding habits, and food rewards. For that reason, these guidelines include a detailed discussion on communicating dietary recommendations to clients in a trust-based, nondefensive manner.

Practice guidelines are consensus statements developed by experts with decades of clinical experience, both evidence guided and anecdotal. These guidelines support the veterinary medical profession’s bioethical obligation to its patients and their owners by giving clinicians the practical means to advocate for pets who cannot represent themselves. Guidelines such as those contained in this report enhance veterinarians’ expertise, which they can leverage on behalf of their patients, thus honoring the principles of clinical bioethics that are the basis of their client-patient relationships.

It is worth noting that individualized nutritional assessments and dietary management require no specialized equipment and can be implemented with little additional time expenditure or cost. Using the approach described in these guidelines, practitioners and their healthcare teams can ensure that nutrition becomes a foundation of good health for their canine and feline patients.

AAFCO (Association of American Feed Control Officials); ACVN (American College of Veterinary Nutrition); BCS (body condition score); BF% (body fat percentage); BW (body weight); CKD (chronic kidney disease); DCM (dilated cardiomyopathy); DEXA (dual-energy X-ray absorptiometry); DHF (diet history form); HPP (high-pressure processing); MER (maintenance energy requirement); MCS (muscle condition score); RER (resting energy requirement); WSAVA (World Small Animal Veterinary Association); USDA (United States Department of Agriculture)

These guidelines were prepared by a Task Force of experts convened by the American Animal Hospital Association (AAHA) and were subjected to a formal peer-review process. This document is intended as a guideline only, not an AAHA standard of care. These guidelines and recommendations should not be construed as dictating an exclusive protocol, course of treatment, or procedure. Variations in practice may be warranted based on the needs of the individual patient, resources, and limitations unique to each individual practice setting. Evidence-based support for specific recommendations has been cited whenever possible and appropriate.

Other recommendations are based on practical clinical experience and a consensus of expert opinion. Further research is needed to document some of these recommendations. Because each case is different, veterinarians must base their decisions on the best available scientific evidence in conjunction with their own knowledge and experience.

These guidelines are supported by generous educational grants from Hill’s Pet Nutrition, Inc., Purina® Pro Plan® Veterinary Diets, and Royal Canin®.