Diet Pet Foods May Pack on the Pounds


Reviewed by Katherine Scott, DVM, DACVIM on January 28, 2010 From the WebMD Archives

Jan. 29, 2010 — Confusing information on pet food labels may make it hard for pet owners to find the right diet food for their overweight dogs and cats.

A new study shows the calorie counts of 44 commercial diet dog foods varied from 217 to 440 calories per cup; the recommended serving size varied from three-fourths to nearly one-and-a-half times as much as the average dog needs to meet daily energy requirements. Similar results were found in 49 diet cat foods.

Researchers say most pets would not lose weight and may actually gain weight based on following the feeding instructions on most diet dog or cat food labels.

“There is so much information — and misinformation — about pet foods, it’s understandable that people are confused about what to feed their dogs and cats,” says researcher Lisa Freeman, DVM, professor of nutrition at Tufts University’s Cummings School of Veterinary Medicine, in a news release. “To counteract these myths, people are accustomed to turning to the labels on food — but, as this study shows, packaging might not always be a reliable source of information.”

Researchers say obesity is one of the most common health problems among dogs and cats, contributing to a variety of diseases, such as pancreatitis, osteoarthritis, diabetes, respiratory disease, and a potentially shorter life span. An estimated 22%-44% of dogs and cats in the U.S. are overweight and obese.

Nutritional Value and Calories

The study, published in the Journal of the American Veterinary Medical Association, evaluated nearly 100 commercially available pet foods that claimed to help dogs and cats with weight management.

The results showed that diet pet foods varied widely in nutritional value and in price — from 4 cents to more than $1.10 per calorie.

Researchers also found a twofold variation in the calorie content and recommended serving size among diet dog and cat foods.

Among their findings:

  • Calorie density among the 44 diet dog foods tested ranged from 217 to 440 calories per cup for dry foods and 189 to 398 per can for canned dog foods.
  • Calorie content for diet cat foods varied from 235 to 480 calories per cup for dry foods and 78 to 172 calories per can for canned cat foods.
  • Recommended serving size for weight loss in dogs and cats ranged from two-thirds to more than one-and-a-half times the animal’s resting energy needs. Eating less than daily resting energy needs is necessary for weight loss for both humans and pets.

According to federal guidelines, pet foods labeled “lite,” “light,” “low calorie,” “less calorie,” or “low calorie” must provide the calorie content information on the label.

These pet foods also must adhere to a maximum calorie amount for weight restriction. But the researchers found more than half of the foods evaluated in the study exceeded this maximum.

Researchers say pet foods that do not make weight management claims are not required to put calorie content information on the label, but efforts are under way to make this information required on all pet foods.

In the meantime, researchers recommend consulting the pet food manufacturer for nutritional information if it does not appear on the label and adjusting the labels’ feeding instructions according to the individual pet’s calorie requirements. Pet owners can consult with their veterinarian for help in calculating their pet’s caloric needs.

Show Sources


Linder, D. Journal of the American Veterinary Medical Association,Jan. 1, 2010; vol 236: pp 74-77.

News release, Tufts University.

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