So many of you have replied to my concerns and I am so grateful. You have each made some excellent pointers and examples. Now ,on this testing procedure; I can understand that a bowl of porridge can be tested before and after as you describe as it is one food (ignoring milk). BUT if I have a dinner comprising several items I won't be sure which food is responsible for the result. Do you really eat a plate of boiled potato simply to do this?. yuk! Then next day similar with a plate of single something else.? I can already sense a lot of smiles for my ignorance - please forgive. thank you ALL for all the previous replies to my "listen to diabetes uk or NHS or magazine articles" delemma, very informative.