Fruit has sugar
but id never suggest to anyone to avoid that. Fructose is low G.I. and Glucose is high GI. Glucose is really the only form the body can use directly so it doesnt require breaking down, whereas other forms of monosaccrides require conversion into glucose, slowing down the process some. When two or more monosaccarides are bound together (glucose+glucose or Glucose + fructose are some examples) these require further breaking down into there core components. However 2 glucose molecules bound together are still absorbed quickley (because its glucose...) whereas a glucose+fructose molecule takes longer because the fructose component slows it down.
Basically, the longer the chain, the slower the absorption process and therefore the less the effect on blood sugar; but this can vary dependant on the molecular structure of the sugars in question. Its not quite as straight forward as you would like to think.
As Rodja has said, don't over complicate it too much. Experiement with diffferent carb intakes etc. but dont make judgement calls after day 1, espcially if you are drastically changing your diet.