Starch and sugar raise blood glucose every time we eat them.
In itself, this is not a problem. However, we now know that carbs having a slow or rapid digestion rate do not have the same metabolic impact. Sugars that are rapidly digested and absorbed, such as those contained in high glycemic index (GI) foods, provoke a sharp increase in blood glucose and raise insulin levels more than complex sugars that are digested at a slower pace (low GI). When high blood sugar and insulin peaks occur on a daily basis, they can impose a metabolic and oxidative stress on the body.
Research is now discovering the health consequences of frequent high post-meal blood glucose spikes. The following articles summarize some of these effects: