Why would parsley and celery be on the no list for diabetic?

I am somewhat pre diabetic.. I got a huge list of what to and what not to eat.. I pretty much just scanned it at the clinic. and after I got home. I saw that I am NOT to eat celery, dried celery flakes, or celery seed (with or without salt).. and the same with parsley... .. just out of curiosity before my next visit in 2 weeks.. I was wondering if any of you knew why?.. is it cause they are diuretics?.. I thought they were healthy.. I couldnt find anything in general on the web about this..