Strange. When I and my husband were still suffering from ME/CFS, eating bananas or strawberries for a couple of days would trigger a relapse. There is something there other than the sugar. Eating apples/pears/grapes and others would have no noticeable effect. I suppose this is an allergic response. However in our previous lives we had not been allergic to bananas and strawberries. And now we can eat both with no problems.