Refined sugar will presumably be sucrose rather than fructose and glucose, so there's an extra step there that the body has to make to break the sucrose down into fructose and glucose, but from that point on it's not immediately obvious why there should be a different response after that has happened. Of course the fact that the sucrose molecule has to be split in the first place may result in a different response.
Another variable is that honey can have significantly varying proportions of fructose and glucose depending on the source whereas refined sugar appears to be roughly half and half. A quick search online suggests that fructose has a much lower GI than glucose and that fructose may result in reduced blood glucose levels.
Could it perhaps be that honey that crystallises fast because of a high glucose content is worse (from a diabetic's point of view) than honey that doesn't due to a high fructose content?
James
