Hi I m dr.hema physiotherapist. I understand your concern. Yes your are correct its good to reduce calcium oxalate levels in your grandsons diet........ Soy protein, and the second is spinach which are rich in oxalates. Cooking does not destroy the oxalates; they are extremely stable. Cooking may reduce the oxalates in foods as they precipitate into the cooking water, and if you discard that water you are likely reducing the oxalates remaining in the food. If you drink that pot liquor, however, you will absorb the full amount. Peppercorns are very high in oxalates, but not many people eat a pound of black pepper every day. However, if you like pepper-coated steaks, pepper may contribute to your oxalate load. The same goes for parsley, it’s very high in oxalates but you don’t eat very much of it. Peanuts and peanut butter are problematic because some kids eat them every single day. Peanut butter is not a poison, so eating it occasionally isn’t going to bother you. The problems come when you make a few highoxalate foods the staples in your diet.