Because it contains low levels of crude fiber and soluble sugars, corn is an ideal food for diabetic patients. For example, the sugar content in old corn is 2.3% lower than that of regular rice, while its crude fiber content is almost 9 times that of rice. These factors are beneficial for diabetic patients in lowering postprandial blood sugar levels. However, there are many varieties of corn, and some are not suitable for diabetic patients to consume. For instance, sweet corn has a soluble sugar content that is 2% to 15% higher than rice, most of which is sucrose, glucose, and fructose, which can easily cause blood sugar levels to rise after consumption.
Furthermore, waxy corn has a high content of amylopectin, making it easily digested and absorbed. It causes blood sugar to rise faster than other grains after consumption, so it is not advisable to eat it alone. It can be paired with bean flour or foods rich in dietary fiber to slow the increase in blood sugar. Most black corn is also waxy, so it is best to consume it with coarse grains such as bean flour or oats.