In the first-ever lifelong canine diet restriction study, Purina researchers  showed that dogs fed to an ideal body condition* throughout their lives had a median life span of 1.8 years longer - and were considerably healthier - than their littermates. Although the dogs in the study generally developed the same health conditions as they aged, treatment for those conditions was delayed approximately two years for the lean-fed dogs.

This study was groundbreaking in a number of ways, and its findings have changed the way we look at the connection between nutrition and health:

• First completed study of its kind to last the entire life span of a larger mammal
• 14-year study conducted at Purina Pet Care Center in Missouri
• 48 Labrador Retrievers were paired, then randomly placed in two different groups
• All dogs received the same 100 percent nutritionally complete and balanced foods - only the amount differed 
• Study documented that feeding to an ideal body condition can extend healthy years in dogs

Study Design – A Lifetime of Information
When the study began, forty-eight Labrador Retriever dogs were paired within their litters according to gender and body weight, and were randomly assigned to either a control or lean-fed group. For the first three years, the control group was fed an unlimited amount of food during 15-minute daily feedings; afterwards they were fed an amount estimated to be the caloric requirement for large breed dogs in “normal” body condition. Each dog in the lean-fed group always received 75 percent of the amount eaten by its paired littermate. All dogs consumed the same diets, which were 100 percent nutritionally complete and balanced (first a puppy formula, then an adult formula) -- only the quantity provided was different.

Dogs were weighed weekly as puppies, periodically as adolescents and weekly as adults. Beginning at six years of age, each was evaluated annually using the Purina Body Condition System, a standard developed by Purina scientists and used by veterinarians to assess body condition in dogs and cats. They were also evaluated annually for body fat, lean body mass and bone mass and other health condition indicators including glucose and fat levels in the blood.

Lean or ideal body condition refers to the evaluation of body physique in pets as an indicator of their overall health and well-being, generally falling into three categories: too heavy, ideal and too thin. But how do you know?

• Too Thin: Ribs are highly visible. Pelvic bones are obvious and prominent and dog exhibits exaggerated waist and abdonimal tuck.
• Ideal Body Condition: Can feel and see outline of ribs. Dog has a waist when viewed from above. Belly is tucked up when viewed from the side.
• Too Heavy: Dog has no waist when viewed from above. Ribs are difficult to feel through the excess weight. Loss of hourglass shape and the belly is rounded when viewed from the side.

Study Results … Extending Healthy Years
Study findings revealed that feeding to an ideal body condition over a lifetime can significantly extend a dog's healthy years - by 1.8 years for the dogs in this study.

The study also showed that the lean-fed dogs maintained a significantly leaner body condition from 6 to 12 years of age than the control group dogs, with mean body condition scores between 4 – 5 (ideal) and 6 - 7 (overfed), respectively. On average, the lean-fed group weighed less, had lower body fat, and after a certain age, experienced a two-year delay in the loss of lean body mass as they aged, compared to the control group dogs.

In addition, according to observations of the researchers, the control dogs exhibited more visible signs of aging, such as graying muzzles, impaired gaits and reduced activity, at an earlier age than the lean-fed dogs.

This study reveals the crucial role ideal body condition plays in health and longevity. However, obesity remains the number one nutritional problem among dogs. Studies have documented that at least 25 percent of dogs in the U.S. may be overweight.

To help maximize their dogs’ health, dog owners should learn how to recognize the signs of obesity and feed to ideal body condition.

* Lean or ideal body condition refers to the evaluation of body physique in pets as an indicator of their overall health and well-being, generally falling into three categories: too heavy, ideal and too thin.