Well, I do know that cantalope will cause
gas if eaten with a meal, which
gas hurts the guts, so I suppose you could try eating those fruits only as a snack, see if that helps. If not, then might be a glucose thing, those items are high in pure sugar, and might be a diabetic sort of thing where the sugar processing part of the body isn't working right. Then some people develop allergies as they get older, stuff they could eat before becomes an allergy thing.