The stone formers will be randomized to receive a low salt+water therapy diet or water therapy alone, for one year. The term "water therapy" refers to an abundant intake of water with a low mineral and low sodium content (at least 2 litres in winter and 3 in summer). For stone formers only, at the end of the 12 month period of therapy, anthropometric parameters and arterial blood pressure will be measured once more and the urinary mini-profile will be repeated.