Eat legumes with abandon. All legumes are digested slowly, causing slow, gradual rises in blood sugar, and thus have low ratings. Add vinegar or lemon juice to foods. Acid slows stomach emptying and digestion. Drinking orange and grapefruit juice also may help.
Acidity explains why yogurt and sourdough bread have low ratings.
Know your starches. White potatoes and sticky cooked rice can raise blood sugar faster and higher than eating sugar or candy. Expect a lower rating from basmati rice, where the grains remain separate when cooked, and brown rice. It's also a myth that pasta makes you fat. Combining dried beans and rice, for example, produces an intermediate glycemic index rating.