Currently rice, wheat, potatoes, yams, cassava, and corn are the world's most important staple foods. High-starch vegetables tend to be roots or tubers like potatoes, yams, turnips, winter squash, carrots, and beets. Yams and sweet potatoes are high-caloric root vegetables. The green leafy vegetables are more chemically diverse and interesting foods that supply less digestible carbohydrate but more vitamins, minerals, and non-digestible fiber. The seeds of 30 or so common legume species are important vegetables, since they are cheap, available and high in protein and fatty acids.
Soybeans are perhaps the most important legume, supplying carbohydrate as well as oil and protein.
Beans, peas, lentils, and peanuts are the other common legumes. The principal sugars are glucose and fructose. These are the simplest CHO molecules, known by their single ring structure as monosaccharides. Glucose is the fuel of all living things, supplying energy to all living cells, both plant and animal. The creation of glucose begins in plants with the magic of photosynthesis.