Food rich in Oxalate to be avoided, like cabbages, spinach, chocolates, black tea/coffee, beets, nuts and rhubarb. Can take rest of foods. Take more citrus containing fruits like daily lemon water and more orange /Malta/ Mosambi, cranberry are also helpful in preventing stone formation. Most important is take sufficient amount of fluid intake , at least 2.5-3 litres in summers and up to 2 litre in winters per day.