Recall that everyone - even normal individuals - are FMs when the fructose load is high enough. A diagnosis of FM is made when there is a change in the level of hydrogen and/or methane breath gas above 20 parts per million after consuming a 25 gram load of fructose. The test does not tell you if you can or cannot handle smaller loads such as 1, 5, 10 etc gram load. It is possible that you have always been a FM but only after after you got IBS did you consciously recognize that FM was causing bloating, etc due to increased sensitivity to GI stimuli.
-------------------- STABLE: ♂, IBS-D 50+ years - Science of IBS