Ingesting large amounts of cornstarch should be avoided, although small amounts are commonly used for cooking with no perceived danger according to the Toxics Use Reduction Institute. Eating large amounts of cornstarch may result in hyperglycemia due to the substance's high concentration of carbohydrates according to Wikipedia.
The consumption of excessive amounts of cornstarch or other purified starches is known as amylophagia, and it commonly affects pregnant women according to Wikipedia. This may be caused by psychological factors, physiological factors or nutritional deficiencies. Some sufferers are compelled to eat pure cornstarch because they enjoy the taste or texture.
According to the USDA website, 100 grams of cornstarch is made up of approximately 91 grams of carbohydrates, making up 30 percent of a person's recommended daily value. It also offers 3 percent of the daily value of iron and 1 percent of protein.
Cornstarch is made by steeping corn for 30 to 48 hours to achieve slight fermentation, and the endosperm is separated from the germ. According to Wikipedia, the endosperm is then ground and washed to remove the starch, which is then dried and purified. The final product is a common thickening agent for sauces, gravy, pudding and other liquid-based foods, and it acts as an anti-caking agent in powdered sugar.