Nuts and stones. Nuts contain oxalate; Calcium oxalate is most common among adults; reasons include: dehydration; excess calcium in urine; excess oxalate in urine; low citrate in urine. Diet: avoid spinach, rhubarb, strawberries, nuts, chocolate, tea, wheat bran, and all dry beans; increase orange juice 8 oz twice daily; add ReaLemon extract: 5 tblspns per day; increase fluid 4 liters/day; only 4 oz meat/day;
Enjoy. Enjoy eating a sensible diet based on what you like and drink plenty of water, unless your physician has very strictly ordered you to monitor your diet. You'll simply trouble yourself trying to keep a "low oxalate" diet and the real key is hydration. Even uncle sam and the lawyers don't emphasize diet as key. http://kidney.niddk.nih.gov/kudiseases/pubs/kidneystonediet/index.aspx#future.