News Release

New study shows people and pets can succeed together in fighting obesity epidemic

Researchers announce results of first-ever, year-long people and pet weight loss study

Peer-Reviewed Publication

Northwestern Memorial HealthCare

Results of the first-ever, 12-month combined people and pet weight management study were presented today at the North American Association for the Study of Obesity's (NAASO's) Annual Scientific Meeting?the largest conference in North America focusing on obesity research and treatment. The People and Pets Exercising Together (P-PET) study by Northwestern Memorial Hospital and Hill's Pet Nutrition, the maker of Science Diet® and Prescription Diet® brand pet foods, demonstrates people and their pets are both more successful in staying with a weight loss program when they exercise together.

The P-PET program is proven to be a safe, effective, and enjoyable way for people and pets to lose weight and maintain weight loss. By participating in a weight loss program with your pet, you can improve the quality of life for you and your pet through increased exercise, a strengthened human-animal bond, and a fun and motivating way to trim down together.

Over 60 percent of adult Americans are now overweight or obese , and an estimated 30 million cats and dogs in the U.S. are overweight or obese?that's 25 percent of the pet population! To combat the obesity epidemic, both public health professionals and veterinarians endorse a proactive approach that includes adoption of healthy changes in diet and physical activity.

Dr. Robert Kushner, Medical Director, Wellness Institute, Northwestern Memorial Hospital and Professor of Medicine, Northwestern University Feinberg School of Medicine and Medical Director of explains, "We devised a state-of-the-art weight management program based on previous studies that show that people are more effective at losing weight and maintaining that weight loss when they do it with a friend or companion. The P-PET study proves that a faithful pet provides effective social support for losing weight and maintaining weight for up to one year."

The 12-month P-PET study consisted of three groups of overweight participants: a dog/owner group (36 people and their dogs), a dog-only group (53 dogs), and a people-only group (56 people). The purpose of the study was to compare the efficacy of weight loss programs for dog-only and people-only groups to that of a combined dog/owner weight loss program for both weight loss and weight maintenance.

During the study, dogs were fed a low-fat, nutritionally balanced food, Hill's Prescription Diet® Canine r/d®, which is specially formulated to help dogs lose weight while keeping them feeling satisfied. In addition, pet owners with dogs in the study were provided with a suggested exercise plan (i.e., 30 minutes of moderate-intensity physical activity at least three days per week) and a regular weigh-in schedule. When the ideal body weight was achieved, the dogs were changed to Hill's Prescription Diet® w/d® food until the 12-month study was completed. People were provided with meal plans and pedometers and were instructed on personality lifestyle pattern behavioral strategies to control dietary calories and increase physical activities.

Dr. Jennifer Jellison, DVM, Practicing Veterinarian Minerva Park Veterinary Clinic, Columbus, Ohio, explains, "People love their pets and don't want to let them down. They also want their pets to live long and healthy lives. Obesity contributes to a shortened life span, heart disease, diabetes, and osteoarthritis in pets, so keeping your pet at a healthy weight is one of the ways that pet owners can strengthen the human-animal bond and help ensure that their beloved pets will be around for years to come."

Over the course of the 12-month study, both people and dogs lost weight and kept it off: people lost an average of 11 pounds (approximately 5 percent of their initial body weight) and dogs lost an average of 12 pounds (approximately 15.6 percent of their initial body weight). The maximum weight loss for dogs was 35 pounds; for people, the maximum loss was 51 pounds. Participants gained the confidence and the motivation to stick to a specific diet and exercise strategies and succeed at weight loss?not just for the moment but for the long term.

"Obesity among pets is one of the most significant nutritional problems seen by veterinarians," states Dr. Dennis Jewell, a companion animal nutrition expert at Hill's Pet Nutrition. "The P-PET program is effective at maintaining participation among people and their pets. With increased retention, dogs should benefit from increased veterinary supervision and owner involvement in weight loss."

Roseann and her dog, Spats, one of the many people and pet pairs who succeeded at losing weight on the P-PET program, learned first-hand how working together could help them both get fit and drop pounds, while spending quality time together. Roseann lost 30 pounds and Spats lost 13 pounds, that's 15 percent of his initial body weight!

"Caring for and loving my dog is what motivated me to be a part of this program," says Roseann. "It is a real lifestyle change. We worked together, lost weight and kept it off over the course of a year, and now there's no turning back!"

The combined dog/owner weight loss program was found to be more effective at maintaining participation than the program in which dogs dieted separately: 80 percent of the dogs in the combined dog/owner group completed the study, versus 68 percent of the dogs-only group. Two-thirds of the increase in physical activity in the combined dog/owner group was obtained by engaging in dog-related activities.

"People really enjoy spending time with their dogs, and our P-PET study demonstrates that dogs provide the companionship, social support, and motivation to stick with the program until the pounds come off and stay off," says Dr. Kushner. "This just might be the ultimate buddy system for winning the battle of the bulge!"

You've heard about Atkins®, The Zone®, and the South Beach Diet®, but maybe you should consult with your dog about your next weight loss endeavor! Check with your doctor and veterinarian before launching any weight loss and exercise plan. For top tips from the experts on how you and your pet can lose weight, visit


About Northwestern Memorial
Northwestern Memorial Hospital (NMH) is one of the country's premier academic medical centers and is the primary teaching hospital of Northwestern University's Feinberg School of Medicine. Northwestern Memorial and its Prentice Women's Hospital and Stone Institute of Psychiatry have 744 beds, more than 1,200 affiliated physicians, and 6,000 employees. Providing state-of-the-art care, NMH is recognized for its outstanding clinical and surgical advancements in such areas as cardiothoracic and vascular care, gastroenterology, neurology and neurosurgery, oncology, organ and bone marrow transplantation, and women's health.

NMH was ranked as the nation's fifth best hospital by the 2002 Consumer Checkbook survey of the nation's physicians and is listed in eight specialties in this year's US News & World Report's issue of "America's Best Hospitals." NMH is also cited as one of the "100 Best Companies for Working Mothers" by Working Mother magazine and has been chosen by Chicagoans year after year as their "most preferred hospital" in National Research Corporation's annual survey. For more information on NMH, log on to

About Hill's Pet Nutrition
Hill's Pet Nutrition, Inc. manufactures Science Diet® brand pet foods, sold through veterinarians and finer pet specialty food stores, and Prescription Diet® brand pet foods, therapeutic pet foods available only through veterinarians. Founded more than 50 years ago by one veterinarian's unique commitment to pet nutrition and well being, Hill's follows its mission to help enrich and lengthen the special relationships between people and their pets by producing the most scientifically advanced, highest quality pet foods available.

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