Tennis great Novak Djokovic talks about his ‘X-factor’ gluten-free diet, prioritising sleep, and the one health item he ...

Djokovic, whose family ran a pizza restaurant, is such a fan of gluten-free diets that he wrote about it in his book, Serve to Win.

At age 38, Novak Djokovic hasn't slowed down much. But retirement might be on the horizon for the Serbian tennis star, who said Friday he may have played his final match in the French Open.