Weight Reduction in the Obese Pet

In 2014, AAHA published comprehensive weight management guidelines, including a detailed protocol for safe weight reduction.2 Because weight loss is a critical aspect of nutritional management for many pets, the 2021 Nutrition and Weight Management Guidelines include an abbreviated overview of this topic. We encourage readers to consult the 2014 Weight Management Guidelines for more complete information on this essential aspect of nutritional management.

Once an animal has gained excess weight, the veterinary team must appropriately inform the owner, gauge their willingness to institute a weight loss program, and offer guidance and support for the duration of the program. The overall design process is reviewed in the 2014 Weight Management Guidelines. Traditional methods to calculate caloric needs are included. 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.57,58 The same principles regarding feeding plans for healthy, appropriate-weight cats and dogs apply for weight loss plans. The major difference is adjusting MER calculations to account for necessary reduced calorie intake to induce weight loss (Box 1). Base these calculations on ideal weight and adjust as needed for the individual patient, based on current intake and lifestyle needs.

Box 1

Energy Requirement Calculations
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View Box 1: Energy Requirement Calculations >

RER = BWkg0.75 X 70
MER = RER X life stage factor

Example for a 10 lb neutered dog:

RER = 4.50.75 X 70 = 216 kcal/day
MER = 216 X 1.4 = 302 kcal/day

Nutritional Assessment Factors

Feline Life Stage Factors*

Canine Life Stage Factors*

Neutered adults



Intact adult



Inactive/obese prone



Weight loss





3.0 (for last 21 days)

Lactation (based on number of offspring and weeks of lactation)


3.0 to ≥6.0



<4 mo: 3.0
≥4 mo: 2.0



Light: 1.6–2.0
Moderate: 2.0–5.0
Heavy: 5.0–11.0

*The above life stage factors are general guidelines for estimating caloric intake. Sedentary and/or indoor pets may require less caloric intake than indicated above.
Adjustment of caloric intake should be done by monitoring BW and BCS.
BCS, body condition score; BW, body weight; MER, maintenance energy requirement; RER, resting energy requirement.

Calculate kg0.75 by using a scientific calculator on most smartphones:

  1. Open the calculator app.
  2. Turn the phone sideways. This should reveal a scientific calculator.
  3. Type the weight in kg. In this example, it would be 4.5.
  4. Press the xy button.
  5. Type in 0.75, then press the = button.
  6. The answer is kg0.75. In this example, it is 3.09.

Table 7

Additional Resources
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ACVN Diet History Form


WSAVA Diet History Form


AAFCO How to Understand a Dog or Cat Food Label


ACVN Board-Certified Veterinary Nutritionist Diplomate Directory


PNA Manufacturer Report


FDA Recalls & Withdrawals


PNA Energy Calculators


USDA FoodData Central


Waltham Puppy Growth Charts


American College of Veterinary Sports Medicine and Rehabilitation Diplomate Search


Find a Certified Canine Rehabilitation Practitioner or Certified Canine Fitness Training Professional


Although the correct calculations are necessary for a successful weight management program, feeding management and activity plans are essential parts of the package. Puzzle toys and automated feeders continue to be invaluable resources that may be especially useful to achieve successful weight loss via improved ease of plan implementation by owners.59,60 Consider collaborating with or referring to a veterinary rehabilitation practitioner (Table 7) to design a comprehensive exercise plan to address desired weight loss while maintaining muscle mass based on the pet’s current level of physical fitness. Use the 2014 Weight Management Guidelines for things to consider with an activity plan.

Long-term monitoring and maintenance are often the most difficult aspects of a weight loss program. Failure to achieve and maintain weight loss is common, and owner nonadherence is a major factor.61–63 After starting a weight loss program, reach out to the owner within the first couple days to determine if there are any immediate concerns. This can be done via phone or email and may help maintain owner adherence and reduce the risk of subsequent dropout.64 Because owners often have a strong human-animal bond with their pets, these first few days may pose the largest obstacle as the owner reconciles a “new normal” that does not involve a constant show of love and affection via provision of food items. Weight management plans should address increasing non– food-related interactions (e.g., walks, playtime, brushing). Postappointment contact can be used to reinforce these recommendations with owners who are struggling with their commitment to the feeding restriction aspect of the plan. The 2014 Weight Management Guidelines outline monitoring and maintenance options. 2 The goal is to be an advocate for both the pet and the owner, while maintaining a nonjudgmental style of communication (see section on Communicating with Clients).

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