If you have been eating wheat without limiting or eliminating it while trying the fructose malabsorption diet then you have not been following the diet properly.
Wheat contains fructans which are molecules made up of chains of fructose molecules linked together. All mammals including humans are incapable of digesting these molecules. They pass through to the large bowel where the bacteria in the bowel ferment them. They can cause gas, bloating and altered bowel habits. For example, soluble fiber supplements that contain inulin or FOS which are fructans are known to cause problems for many IBS suffers. Heather talks about inulin on this web page
It appears that while some people may not be sensitive to the excess fructose in fruits they may have problems with the fructans in wheats and vegetables like artichokes, asparagus, onions and garlic. You have to follow the diet closely in order to determine if you truely are fructose sensitive.
By the way - nuts are high in IF and like many high IF foods they can cause gas, bloating and act as a laxative. If you are going to eat nuts then it is wise to grind them up fine and eat them sparingly with a good SF base.
-------------------- STABLE: ♂, IBS-D 50+ years - Science of IBS