Majority of fructose is not found by itself, but forming a dimer with glucose, for a final form we are all familiar with: Sucrose. Refined fructose is as artificial as refined glucose (okay, maybe not as much, the proportion of free fructose in several fruits really is higher than that of free glucose, but it's still much less common than sucrose). You are correct that free glucose is not something we typically would come to have in great quantities as a free sugar in our diets, we'll either eat it as sucrose (with the rest of the fruit/vegetable), or in a polysaccharide form (i.e., starches and the like). The way free glucose hits our pancreas as spikes insulin isn't really something the body should be doing. Bottom line is, use sucrose for a balance between insulin-spiking and more slowly digested fructose, never on its own, don't abuse it, and better yet, use as much natural product as possible (just eat fruit dammit!). And avoid fructose and glucose syrups!