A 14-year study of canine diet and health has found that dogs fed a calorie-restricted diet live a median 1.8 years longer than dogs allowed to eat more and are slower to develop chronic diseases such as osteoarthritis.
The findings add to the growing body of evidence that caloric restriction in a wide range of species significantly boosts longevity. Dogs are the only large mammals, and the closest human relatives, for which a diet-restriction study has been completed.
The study involved 48 Labrador retrievers from seven litters. Litter-mates were paired, with one dog fed 25 percent fewer calories than its sibling starting at 8 weeks of age. The researchers found a median life span of 13 years among dogs whose food intake was reduced, while dogs in the group fed a diet higher in calories were uniformly overweight and had a median life span of 11.2 years.

"Impressive as they are, the life span figures are only part of the story," said Gail K. Smith, professor of orthopedic surgery at Penn and chair of the Department of Clinical Studies at the School of Veterinary Medicine's Philadelphia campus. "The study also showed that lean body conformation forestalls some chronic illnesses, most notably osteoarthritis, and that diet can either mitigate or exacerbate the expression of genetic diseases. "This study should reinforce for dog owners the importance of keeping their dogs lean, with palpable ribs and an obvious waistline," Smith said. "Avoid giving dogs too many high-calorie treats and consider a brand of balanced dog food formulated to be low in caloric content while providing a sense of satiety."

Research spanning decades has found that dietary restriction is the only nutritional change that consistently extends the life span of animals.

WHO IS THE WORLD'S WORST WATCHDOG?
We nominate a 'Guard Dog' Beat Up by the Cat and then Stolen

Dognews, Oct., 2002

Who is the World's Worst Watchdog? Excluding "Wags" (who is so lazy that he waits for another dog to bark and then just nods his head), OZ is another worthy contender.