New potatoes, versus older potatoes:

""Different kinds of starch have different arrangements of molecules, and some are easier for our digestive enzymes to get at than others. One kind of starch, called amylose, is broken down quite slowly. The higher the amount of amylose in a starch, the more slowly it is digested. New potatoes (sometimes described as "waxy") have a starch that is closer to amylose in structure than more mature potatoes, and they are somewhat less "glycemic". (Glycemia is the related noun meaning glucose or sugar in the blood).

High glycemic food cause a larger rise in blood glucose, which can last for a longer time as well. Low glycemic foods tend to cause small blood sugar rises that don't last as long. Foods with a lot of sugar in them tend to be very glycemic. People are sometimes surprised to hear that the starches in foods such as potatoes, bread, and grain products are made up of long strings of glucose, so these foods can be as or more glycemic than sugary foods.""

Now, don't that turn your brown spuds blue?