Plants store glucose in the form of starch, which is a polysaccharide. Polysaccharides are used by the body for structural support and as a source of energy, according to Elmhurst College’s Virtual Chembook. Your body begins to digest starch as soon as it enters your mouth, via salivary enzymes that break it into smaller molecules. Further along the digestive tract, pancreatic juices and enzymes found in the lining of the small intestine break down starches first into maltose and then into glucose. A number of fruits and vegetables are high in starch.
All kinds of potatoes, including sweet potatoes, are high in starch, according to the University of Michigan Health System. These foods are typically low on the glycemic index, which makes them good choices for people who are trying to manage their blood-sugar levels. Starches contain about 15 g of carbohydrates, 3 g of protein, 1 g of fat and 80 calories per serving, or exchange, for those following a diabetic diet. According to MayoClinic.com, one quarter of a large baked potato with the skin on equals one exchange serving, as does 1/2 cup of yam or sweet potato served plain.
Squash, the plant group that includes acorn, butternut squash and pumpkins, are conventionally thought of as vegetables, though botanically speaking, they’re actually fruit. Pumpkins are low in calories, rich in potassium and loaded with beta-carotene, an important free-radical-fighting antioxidant. A cup of canned pumpkin provides one exchange serving, for those following a diabetic diet. A cup of either acorn or butternut squash is also equal to one exchange.
Corn, whether it’s on the cob or ground up to form corn meal, is a rich source of starch. The University of Michigan Health System states that starchy vegetables such as corn are metabolized slower than simple sugars and more like a grain. They contain fiber, nutrients and phytochemicals and provide the brain and the nervous system with energy. Polenta, a corn-meal mush, can be prepared to serve as the central starch in a meal. Corn is gluten-free, thus can be tolerated by those with celiac disease, also known as gluten intolerance.
Most foods that are traditionally thought of as fruit are not typically high in starch, but plantain is an exception. This banana-like staple of Mexican cuisine contains about 45 g of carbohydrate per cup and was found have the highest concentration of starch in a study comparing various Mexican fruits and vegetables, according to Castillo Sanchez of the Salvador Zubiran National Institute of Nutrition in Mexico.