Eating high oxalate foods daily and for extended periods of time, can cause a build up of oxalic acid in the body tissues, bones, organs, blood vessels, skin, and dramatically irritating nerves.   It is considered a hidden medical problem resulting in what is referred to as soft neurology complaints without objective findings.  It does not show up on blood / urine lab test or imaging studies.   In severe cases in will be the culprit of Kidney Stones (calcium-oxalate stones).
In the future I will add further comments.
 
Rather than presently go into dietary recommendations, the author 
 has done a terrific job in explaining and providing dietary recommendations in her two books:      Also available a downloadable PDF dietary list
 
                 Toxic Super foods                                      Data Companion handbook
                                                                                      (Diet Recommendations)