Becky, I just saw this thread today, I need to look more carefully. Your variation can definitely depend on what you are eating, especially it you are looking at tests taken two hours after eating. Some types of carbs act much more quickly than others. If you had a breakfast with white bread, milk and a banana then you would have high blood sugar two hours later because the carbs in those foods act very quickly. There is very little protein in that meal too, so the carbs would act even faster than if protein had been included. This morning I had two scrambled eggs with bacon, a low carb slice of whole grain toast, a small tangerine and a cup of coffee. Lots of protein and nothing with very fast acting carbs. My blood sugar was only 18 points higher two hours later. That was a 24 carb meal. You might try following the Glycemic Index thread or research it on Google. That will tell you the best foods for not raising your blood sugar so fast.
http://www.diabetesforum.com/diabetes-diet-nutrition/1909-glycemic-index.html
http://www.diabetesforum.com/diabetes-diet-nutrition/1909-glycemic-index.html