2021 AAHA Nutrition and Weight Management Guidelines for Dogs and Cats Executive Summary

The 2021 AAHA Nutrition and Weight Management Guidelines for Dogs and Cats discuss the components of a systematic approach to nutritional management of dogs and cats. This Executive Summary provides selected highlights of the guidelines.

Note: This Executive Summary provides selected highlights of the guidelines. It is not a replacement for reading the guidelines in their entirety.

by Constance Hardesty, MSc

The 2021 AAHA Nutrition and Weight Management Guidelines for Dogs and Cats discuss the components of a systematic approach to nutritional management of dogs and cats. These guidelines update and complement previously published but still relevant nutrition-related guidelines produced by the American Animal Hospital Association, the 2010 AAHA Nutritional Assessment Guidelines for Dogs and Cats, and the 2014 AAHA Weight Management Guidelines for Dogs and Cats.

For tables, figures, and the box mentioned in this executive summary, see the 2021 AAHA Nutrition and Weight Management Guidelines.


The World Small Animal Veterinary Association (WSAVA) recommends nutrition as the fifth vital assessment to optimize the health and well-being of pets. The AAHA Advisory Panel endorses this recommendation.

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.

To help practices implement a comprehensive and systematic nutritional program, these guidelines address recommendations and implementation in three broad areas: nutritional assessment and recommendations, client communication, and teamwork.

A nutritional assessment including body condition score (BCS) and muscle condition score (MCS) of canine and feline patients is the initial step. The assessment should be performed on a regular basis throughout all pet life stages, ideally at each exam visit. Based on the assessment, patient-specific nutrition recommendations can be made. These recommendations often have specific therapeutic goals, such as weight loss or dietary support of chronic or acute disease conditions.

Client attitudes toward pet nutrition are often based on individual biases and strongly held beliefs. For this reason, eŽective client communication is important in achieving adherence with dietary recommendations. To ensure that the client has a positive perception of nutritional recommendations, nutrition conversations should focus on both the message and the communication process, taking into consideration the client’s views on topics such as pet food choice, dietary rewards, and weight control. Integrating nutritional management as a vital part of the practice’s culture requires the expertise and commitment of the entire veterinary team.

How to Perform a Complete Nutritional Assessment

The nutritional assessment is an iterative process that requires repeated assessment over the animal’s lifetime. The assessment should evaluate factors in three broad categories: animal-specific, diet-specific, and feeding management (Figure 1). Several factors in these categories (e.g., adverse food reactions, nutrient imbalance, competitive eating) are listed in the guidelines’ Table 1. A nutritional assessment comprises two parts: a screening evaluation for all pets and an extended evaluation as needed.

Screening evaluation

A screening evaluation should be performed on every pet at every visit. The screening (see Figure 2) should evaluate the pet’s nutritional history, environment, activity level, body weight (BW), BCS, and MCS, followed by a complete physical exam.

To improve accuracy, pet owners can complete the diet history at home, and it can be checked by practice team members.

If nutritional risk factors are identified, an extended evaluation is recommended. The guidelines other helpful information and pointers to online tools, including components of a comprehensive nutrition history such as main meal, table food, supplements, and so on (Figure 5); links to diet history forms (Table 7); the 9-point WSAVA BCS chart (Figure 3); and the WSAVA MCS chart for dogs (Figure 4). Links to canine and feline BCS and MCS tools appear in footnotes 7, 8, 12, and 13. Table 2 correlates BCS scores to body fat and body weight. And clinically relevant nutrition terms are defined in Table 3.

Body fat index, girth assessment, and fecal scoring also may be useful. Limb girth, an emerging assessment, may prove valuable.

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For hospitalized patients, a nutritional assessment should be performed on admission and at least daily, and feeding orders should be written and assessed daily. BW needs to be checked at least daily to assess hydration status. The guidelines discuss what information to gather about hospitalized patients and what topics to cover in their feeding orders.

Nutritional risk factors

The initial screening evaluation may reveal risk factors that require an extended evaluation. The guidelines and Table 4 refer to several risk factors related to life stage, medical/dietary history, and physical examination, such as lactation, inadequate housing, or unexplained weight change, respectively.

Extended evaluation

The extended nutritional assessment is an opportuniƒ to gather a more comprehensive nutritional history and pursue clinical diagnostics as indicated by abnormal physical exam findings, areas of concern in the nutritional history, and nutritional risk factors. Table 5 lists some diagnostic tests suitable for an extended nutritional assessment. Medical conditions or diseases may benefit from nutritional interventions (see Table 8).

How to Create Individualized Nutritional Recommendations

Apparently healthy patients maintaining ideal weight may not require major diet adjustments unless a nutritional risk factor is identified.

When making new feeding recommendations, consider the feeding plan, gradual adjustments to the pet’s diet, and feeding management and environmental factors such as food-dispensing toys.

The guidelines devote special attention to areas of interest such as whether a diet is complete and balanced, the overall quality of a commercial diet and its feeding instructions, and a calculation to determine suitable caloric intake (see Box 1).

Recommendations for hospitalized patients address caloric intake, support for anorexic or hyporexic patients, medication support, and protocols that promote enteral nutrition over parenteral nutrition. Because of the risk of food aversion and aspiration, oral syringe feeding is no longer recommended.

Obesity prevention and weight reduction

The guidelines devote significant attention to obesity prevention, weight reduction, and therapeutic diets to promote weight loss. Proper weight management will support the patient’s overall quality of lie, may extend lifespan, and can help to prevent or mitigate comorbidities.

Potential risk factors for obesity range from breed predisposition, age-related metabolic changes (for example, lower energy requirements in dogs and reduced digestibility in cats), and health conditions (spay, neuter, hypothyroidism), to feeding and exercise patterns (including clients’ underestimating pets’ caloric intake and overestimating their exercise). A lengthy list of risk factors appears in Table 6.

To prevent obesity, compare reported intake against calculated requirements based on ideal BW and make downward recommendations. Reassess and adjust as needed at subsequent visits.

Once an animal has gained excess weight, appropriately inform the owner, gauge their willingness to institute a weight loss program, and other guidance and support for the duration of the program. The process is presented in full in the 2014 Weight Management Guidelines, which readers are encouraged to consult for more complete information.

Recent data suggest mean caloric intake for weight loss over a 12-week period is 63 ± 10.2 kcal/kg0.75 in dogs and 52 ± 4.9 kcal/kg0.711 in cats. The same principles regarding feeding plans for healthy, appropriate-weight cats and dogs apply for weight-loss plans. The major diŽerence is adjusting MER calculations for reduced calorie intake; a calculation is given in Box 1.

The guidelines recommend therapeutic weight loss diets fortified with nutrients for patients undergoing significant calorie restriction for weight loss. High-protein diets can spare lean mass with calorie restriction. Protein and added fiber can promote satiety, while added fiber will also reduce caloric density. High-moisture diets for cats may increase satiety.

Feeding management and activity plans are essential parts of a weight-loss effort. Activity plans are discussed in the 2014 Weight Management Guidelines. A veterinary rehabilitation practitioner can help to design an exercise plan (see Table 7).

The 2014 Weight Management Guidelines provide options for long-term monitoring and maintenance, which are often the most difficult aspects of a weight loss program. In addition, the 2021 guidelines offer some tips for helping clients commit to feeding restrictions.

Therapeutic diets not related to weight loss

When the nutritional assessment indicates a patient may benefit from a purpose-formulated therapeutic diet, the clinician needs to focus on specific nutrients of concern. The guidelines outline an approach for this, and nutrients of concern for selected diseases and conditions appear in the lengthy Table 8.

For diseases in which diagnostics and staging affect nutrients of concern (e.g., CKD) or when patients have multiple disease conditions and/or additional feeding or diet requirements, consider all nutrients of concern before selecting a diet.

Communicating with clients

Communicating about nutrition may require difficult and complex conversations. Success involves managing the message, the communication process, and issues related to perception; seeing past your personal biases to acknowledge (while not accepting) the client’s perspective; and enlisting every member of the practice team to reinforce core messages.

The guidelines other insights and advice about key milestones in the communications process, including:

  • Gathering a comprehensive nutrition history
  • Communicating a nutrition recommendation in six steps
  • Managing challenging nutrition conversations
  • Navigating the emotional connections
  • Intrateam communication

An effective, comprehensive nutritional history begins with open-ended questions, moves on to more focused questions, and ends with close-ended questions (see Table 9). A good open-ended question is, “Tell me your thoughts on his/her current diet.”

A common obstacle to successful nutrition recommendations is that the recommendation does not align with the client’s own goals or beliefs. Developing a nutrition recommendation is an iterative process in which it may be necessary to return to the nutrition history to gather additional information to better align a recommendation with the client’s goals and beliefs (see Figure 6).

Communicating a nutrition recommendation involves initiating the recommendation, exploring all options with the pet owner, educating them about each option, making a clear recommendation, soliciting feedback to modi« the recommendation, and planning follow-up actions.

The guidelines even suggest words to use or avoid in communicating with clients; for example, avoiding the word “treat” and questions beginning with the word “what.”

Clients may suspect the veterinarian has a financial motive in recommending a commercial pet food. To allay their suspicions, divide the recommendation into two parts. First, recommend a nutrition change as a preventative or to address a health concern. Second, if required, recommend a product-specific commercial diet to support the healthcare decision. Separating these recommendations teases apart the question of motivation (business versus healthcare) behind an overall nutrition recommendation.

Pet feeding is an emotional topic that requires careful navigation. The guidelines discuss clients’ emotional connection to feeding choices and explain how the veterinary team can work with clients to understand and accept nutrition recommendations.

Weight is not the only sensitive topic that comes up in conversations about pet nutrition. Other challenging topics include wet versus dry food, unconventional food choices, and use of nutraceuticals.

Other Timely Topics of Interest

Timely topics that are briefly discussed include diet-associated dilated cardiomyopathy; home-prepared diets; raw protein diets; age-specific and breed-specific diets; and microbiome, prebiotics, and postbiotics.

The Advisory Panel has provided current information on nutritional topics of interest. However, as dietary information is an evolving science, practitioners should make note of new developments that postdate the guidelines.

A Team Approach

Integrating nutritional assessments requires a committed and engaged team. Veterinary technicians are poised to lead the initiative, and group effort increases efficiency by distributing workload and delivering an integrated, cohesive message.

The effort begins with obtaining the diet history before the appointment, proceeds through assessment and recommendation, and continues with follow-up and accountability. The guidelines lay out step-by-step suggestions for involving the client service team, veterinarian, and veterinary technician.

Some ways to fine-tune an accountability program include pairing each patient with a specific team member, setting rules for the assessment and accountability program (e.g., assessment appointments should be scheduled separately from wellness or preventive care appointments), offering a small gift to recognize the client’s investment in supporting their pet’s optimum health, and recognizing that clients involved in a pet weight-loss program enter the practice more frequently, providing multiple opportunities to address other medical issues.


A unified approach to implementing an eŽective nutrition program will promote optimal pet health, therapeutic success, a strong veterinarian-client-patient relationship, and a long-term client association with the practice.

Constance Hardesty
Constance Hardesty, MSc, is a writer and freelancer living in Colorado. She is a former editor-in-chief at AAHA.


Photo credits: anastas_/iStock via Getty Images Plus, Lightspruch/iStock via Getty Images Plus



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