By Carmela Stamper, DVM, FDA Center for Veterinary Medicine
This is a true story; only the name and coat color have been changed to protect the innocent.
Rosie was a sweet girl; a happy black Labrador retriever, who, like many labs, lived to eat. Food on the kitchen counter? Kiss it goodbye. Counter-surfing was a rewarding daily sport in Rosie’s house. Unopened loaves of fresh bread were a particular target—a tasty mid-day snack, plastic bag and all.
When Rosie damaged both her knees at a young age, she began to have difficulty moving around, especially after arthritis set in. Her human mom, feeling badly for Rosie and knowing that eating was Rosie’s greatest joy in life, fed her more than an inactive, arthritic, young dog needed. Cutting back the amount of food she fed Rosie was, emotionally, not an option.
As time went on, Rosie gained weight. And she gained more weight. Rosie was a 75-pound lab now trapped in a 150-pound body; she could hardly walk. When she tried to get up after laying down, she looked like a rearing elephant seal—pushing and propping herself up with her front legs, rolls of fat rippling down her back. A simple change in position was difficult; walking occurred only when necessary. So, at 8 years old—middle-age by Labrador retriever standards—Rosie died of liver disease caused by her obesity.
Obesity is a common topic these days, whether in newspapers, online, or on TV. More than one-third of American adults are obese.1 According to the Centers for Disease Control and Prevention, 17 percent of U.S. children and adolescents are obese. But what, exactly, is obesity?
Obesity is a term simply meaning excess fat tissue in the body.2, 3 Although people may think of fat as relatively harmless or somewhat inconvenient, it is anything but. The fat in a person’s body, like the fat in an animal’s body, is made up of many tiny cells. These cells make various hormones, like insulin, and secrete these hormones directly into the bloodstream. (Hormones are special chemicals that regulate certain cells or organs in the body.)
In a person or an animal with low body fat, the amount of additional hormones produced by fat cells is small because there aren’t many fat cells. However, in people or animals with higher body fat and more fat cells, a greater amount of additional hormones is secreted into the bloodstream, negatively affecting the body. Obesity leads to a variety of diseases including: Type 2 diabetes mellitus, high blood pressure, gallstones, fatty liver disease, sleep apnea, heart failure, degenerative joint disease, asthma, and cancer.4
Just as obesity has become a serious problem in people, it is also a growing problem in their pets. According to the Association for Pet Obesity Prevention, 54 percent of dogs and cats in the U.S. are overweight or obese. The diseases seen in these pets are eerily similar to those reported for people: Type 2 diabetes mellitus, osteoarthritis, high blood pressure, heart and respiratory disease, kidney disease, and shortened life span.5
Obesity is a complex disease in people. Genetics, environmental factors, other diseases, and medications all may play a role. It’s a similar story in pets. There are pet-specific factors, such as if the pet is on any medications or has a disease that contributes to obesity; environmental factors, such as not enough exercise and how the pet is fed by the owner; and genetics, with some breeds more prone to being overweight. Studies show that weight loss in pets improves their overall health by:
- Improving respiratory function,
- Decreasing osteoarthritis in shoulder, hip, and elbow joints,
- Lengthening the median life span in dogs, and
- Delaying the onset of chronic diseases in dogs.6, 7, 8
Guidelines for People, Guidelines for Dogs and Cats
The U.S. Department of Agriculture (USDA) and the Department of Health and Human Services jointly created the Dietary Guidelines for Americans to address proper nutrition and the prevention of diet-related diseases in people. The nutrition and health experts in both departments re-evaluate current science and medical knowledge every 5 years and use that information to revise the guidelines when necessary.
Until 2010, the guidelines provided nutrition advice for healthy Americans over the age of 2 years. The latest revision, released in 2015, addresses this healthy population and those Americans at an increased risk of obesity-related diseases. The guidelines, written for the general public, provide recommendations on how to eat healthy and maintain proper calorie balance (calories in equal calories out) to prevent becoming overweight or obese. An easy–to–understand picture, the USDA Food Plate, is a companion to the guidelines and gives people a visual example of proper food portions on their dinner plates (http://www.choosemyplate.gov/).
Unfortunately, similar dietary guidelines don’t exist for pets. In summer 2010, however, the American Animal Hospital Association (AAHA) released a document written for veterinarians and their staff, entitled AAHA Nutritional Assessment Guidelines for Dogs and Cats. The association drafted the document because “good nutrition enhances pets’ quality and quantity of life, and is integral to optimal animal care.”9 The guidelines give veterinarians and their staff a no-cost, quick way to obtain crucial nutrition information for pets. Using this information, veterinarians are better able to help pet owners make better decisions about their pets’ nutrition and overall health.
The nutritional assessment provides veterinarians and their staff with:
- An increased awareness of the importance of nutritional assessments in dogs and cats,
- A set of guidelines to help evaluate the nutritional health of dogs and cats, and
- More evidence and better tools to support recommendations about nutrition to pet owners.
According to the AAHA guidelines, a screening nutritional assessment should be performed on every dog and cat as part of a routine physical examination. Based on the assessment, the veterinarian, with the pet owner’s input, creates an action plan that the owner will likely follow. The goal of the action plan is to help keep the pet in good health.
The screening assessment includes a checklist of the following risk factors for obesity:
- Altered gastrointestinal function (for example, vomiting, diarrhea, flatulence, and constipation),
- Previous or ongoing medical condition or disease,
- Current medications and/or dietary supplements,
- Unconventional diet (for example, a raw, homemade, or vegetarian diet),
- More than 10 percent of the pet’s daily calories from snacks, treats, and table food,
- Uneducated pet owner regarding how much, or what diet, to feed the pet, and
- Inadequate or inappropriate housing (for example, the pet is caged much of the day and doesn’t get enough exercise).
The screening assessment also includes a checklist of physical examination factors for the veterinarian to evaluate:
- Body condition score (a body fat score based on body shape and how the body feels as the veterinarian runs his or her hands over the pet),
- 1 to 5 point scale, with 2.5 to 3 as the target scores
- 1 to 9 point scale, with 4 to 5 the target scores
- Muscle condition score: mild, moderate, or marked muscle wasting (muscle loss),
- Unintended weight loss of 10 percent or more,
- Dental abnormalities or disease,
- Poor skin or hair coat, and
- New medical condition or disease.
If the veterinarian finds that the pet has any of the risk factors for obesity on the checklists, the guidelines suggest performing a more in-depth, or “extended” evaluation.
Keeping Pets Nutritionally Healthy: The Circle of Nutrition
The screening assessment above and the extended evaluation for a pet at-risk for nutrition-related disease revolve around what the American College of Veterinary Nutrition (ACVN) calls the “Circle of Nutrition.” According to ACVN, a comprehensive approach to animal nutrition can be represented as a circle containing three interrelated components. Each component represents a different nutritional aspect for veterinarians to assess in each patient:
- The Pet
“Animal-specific factors” include basic information about the pet, such as age and level of activity, and if the pet has any health issues. This information helps the veterinarian determine the appropriate nutrition for the pet. For example, a young pet has different nutritional requirements than a senior pet, and a hunting dog needs more calories than a lapdog.
- The Pet’s Diet
“Diet-specific factors” determine if the pet’s diet is appropriate and safe. For example, the owner may be inappropriately feeding puppy food to a senior dog, or the diet may have recently been recalled for safety concerns. Some of the safety concerns related to pet food include:
- Improper storage, whether at the warehouse or the owner’s house,
- Adulteration10, like the melamine tragedy (for more information on the melamine tragedy, visit the CVM web page at: Melamine Pet Food Recall of 2007,
- Contamination with disease-causing bacteria or fungi, and
- Nutrient imbalances, such as the past pet food recalls on thiamine-deficient diets and diets containing too much Vitamin D.
- Feeding Management and Environmental Factors
Feeding management and environmental factors include information like:
- How much food does the owner feed the pet and how often?
- Does each pet have a separate food bowl or is there a shared food bowl?
- Does the pet get treats, and if so, how many? (Treats add extra calories that owners may not think about.)
- Is there competition among pets in the house such that one pet gets more food than the others?
Body and Muscle Condition Scoring Systems
Besides providing veterinarians with sample checklists, the AAHA guidelines also give examples of body and muscle condition scoring systems. The guidelines recommend that, in addition to being weighed (preferably on the same scale each time), every dog and cat should have a physical evaluation of its body and muscle condition at each visit. All veterinarians in the clinic should use the same scoring system to decrease the variability in condition scores. These scores will vary somewhat because they are subjective, meaning they are based on a veterinarian’s opinion of the pet’s body at that time. Having all veterinarians in the clinic use the same scoring system makes the scores more consistent.
The body condition scoring (BCS) system is easy to learn and requires little effort to record in the chart.11 The BCS system uses pictures, words, and numbers to help veterinarians and their staff quickly determine body fat levels in dogs and cats. Optimum body condition scores for cats and dogs range from 2.5 to 3 on a 5-point BCS scale, to 4 to 5 on a 9-point BCS scale. The system’s pictures are helpful in showing what pets look like at various scores. The written descriptions, although potentially a bit too technical for pet owners, describe what a pet should look and feel like at each score.
The AAHA guidelines give an example of a 9-point scale (https://www.aaha.org/globalassets/02-guidelines/nutritional-assessment/nutritionalassessmentguidelines.pdf).
For an example of a 5-point scale, visit the Association for Pet Obesity Prevention’s website at http://www.petobesityprevention.com/pet-weight-check/.
Unlike the body condition scoring system, which measures body fat, the muscle condition scoring (MCS) system looks at the amount of muscle an animal has (muscle mass). Like the BCS system, the MCS system uses pictures and written descriptions but no number score is assigned. Muscle mass is determined by pressing specific bony points on a pet’s body and seeing how far the veterinarian’s finger sinks into the body. Veterinarians can’t easily feel those points if the pet has a lot of muscle mass. As a pet loses muscle mass (muscle wasting), the bony points become easier to feel. Veterinarians describe the degree of muscle mass loss as “mild,” “moderate,” or “severe.” Sick pets are more likely to lose muscle mass, which can decrease their immunity, physical strength, and ability to heal wounds.12
Communication is Key
An action plan is only successful if it is actually followed by the owner. The responsibility for success is shared by the veterinarian and the pet owner. Open communication is crucial during the nutritional assessment, action plan creation, and follow-through stages. Veterinarians need to give pet owners the reasons for the action plan recommendations. Pet owners need to be honest and let the veterinarian know when they feel they cannot carry out certain recommendations. In the end, both parties want the pet to be healthy.
It’s unclear if Rosie ever had routine nutritional assessments. A good nutritional assessment and action plan could have helped her live a healthier life. As the number of pet obesity cases rises, the AAHA Nutritional Assessment Guidelines for Dogs and Cats may provide veterinarians with the tools they need to help the Rosies of the world live happier, longer, and more active lives.
3 http://www.cdc.gov/obesity/adult/defining.html (obesity is defined by a body mass index score in people of 30 or greater; 18.5 to 24.9 is considered normal)
6 Bach JF, Rozanski EA, Bedenice D, et al. Association of Expiratory Airway Dysfunction with marked obesity in healthy adult dogs. 2007. American Journal of Veterinary Research 68(6):670-675.
7 Kealy RD, Lawler DF, Ballam JM, et al. Evaluation of the effect of limited food consumption on radiographic evidence of osteoarthritis in dogs. 2000. JAVMA 217(11):1678-1680.
8 Kealy RD, Lawler DF, Ballam JM, et al. Effects of diet restriction on life span and age-related changes in dogs. 2002. JAVMA 220(9):1315-1320.
9 Baldwin K, Bartges J, Buffington TA, et al. AAHA Nutritional Assessment Guidelines for Dogs and Cats. 2010. Journal of the American Animal Hospital Association. 46:285-296.
10 "Federal Food, Drug, and Cosmetic Act. Sections 402--Adulterated Food: http://www.gpo.gov/fdsys/pkg/USCODE-2010-title21/pdf/USCODE-2010-title21-chap9-subchapIV-sec342.pdf, and 501--Adulterated Drugs and Devices: http://www.gpo.gov/fdsys/pkg/USCODE-2010-title21/pdf/USCODE-2010-title21-chap9-subchapV-partA-sec351.pdf."
11 Burkholder WJ. Use of body condition scores in clinical assessment of the provision of optimal nutrition. 2000. JAVMA 217(5):650-654.
12 Baldwin K, Bartges J, Buffington TA, et al. AAHA Nutritional Assessment Guidelines for Dogs and Cats. 2010. Journal of the American Animal Hospital Association. 46:285-296.