I always do 1/2 cup of GFJ and 1/2 cup of OO (Olive-Oil) and although I feel very nauseous and burp up the mixture I've never actually vomited(22flushes so far).What has really helped me recently is adding a good chunk of ginger with the mixture,juice it with the grapefruit.Also,elevating your head with extra pillows will help.Good luck and happy flushing.