This study investigates the impact of long term dietary restriction in dogs, particularly during the second decade of life. Forty-eight Labrador retrievers paired by sex and weight at 6-weeks-old, were randomly assigned to control feeding (CF) or 25% diet restriction (DR) with the same diet from the age of 8 weeks. DR dogs had 1.8 years longer median lifespan and delayed onset of diseases associated to age such as osteoarthritis, as well as 17% less energy requirement to maintain each lean kg. Signals from gut microbiota may be involved in the DR longevity and health responses as suggested by metabonomics-based urine metabolite trajectories.