Glycæmic Index is influenced by:

Fibre type: soluble fibre slows down the digestion of starches and the absorption of glucose into the bloodstream e.g. oat fibre (oats, oat bran, oat fibre flour), fruit pectin (especially cold climate fruits), legume fibre (baked beans, lentils etc) and psyllium (Metamucil, Fybogel). Porridge has a lower Glycæmic Index than Weetbix (has only when bran) and plums have lower Glycæmic Index than watermelon.