New York - Novak Djokovic attributes his success in recent years to a change of diet.
Now he'll be sharing his nutrition tips in a book to be released before the U.S. Open.
"Serve to Win" is the title of Djokovic's "nutrition-based performance guide" that is to be published next month.
The top-ranked Serbian has won six of his seven Grand Slam tournament championships since adopting a "performance-focused" gluten-free diet in late 2010.
In 2011, he took the Australian Open, Wimbledon and the U.S. Open.
He has since won two more Australian Opens, along with the 2012 French Open.
Djokovic says that discovering the right diet for him has made "all the difference," on and off the court.
The book will be published by Ballantine Bantam Dell, part of Random House.