Hello Seb,
Too much sugar can lead to candidas... I think it is much easier to develop on this diet as we may replace starch with too much sugar.
I have had 3 episodes of candidas... I eat a lot of raisons on diet... but not an issue. If I add honey and/or vinegar on regular basis as well I have always run into candidas issues. This pain feels just like my AS pain.
To get rid of candidas I come off all sugar for couple of weeks, take natural garlic twice daily and sometimes orgeno oil.
As for grapes... I love them, but agree to many cause me stomach noises and some discomfort in intestines. In moderation I have no issues.
Tim