Thanks Lily! Thats very interesting, I know on S&S we are advised against citric acid yet they sell water flavour with it in- very confusing! Sadly I think experimenting to see if I am affected by citric acid will be counter-productive, either I'll kick myself out of ketosis or will find I can have citric acid increasing the range of things I can eat- not what I want at all, the VLCD is meant to be restrictive.