Starch is a fundamental nutrient that provides between 20% and 40% of energy for most individuals. Starch is a complex polymer of glucose, but starch-containing foods can provide significant fiber, protein, and micronutrients although these are highly variable. This article will examine the differences between the various starch polymers, the difference between highly refined sources of starch and less refined sources, and the major sources of starch – rice, wheat, maize, potatoes, sorghum, yam, cassava, plantains, rye, oats, barley, and legumes – and the health effects of these different sources.