Understanding the difference between simple carbohydrates (unhealthy) and complex carbohydrates (healthy) allows us to have a diet that contains the carbohydrates our body needs to ensure a constant supply of energy. Some fruits such as bananas, watermelon and fruit juices are also high in sugar and can cause blood sugar fluctuations as well. Simple carbohydrates are easily degraded in the body and can supply energy very quickly. It raises blood sugar level quickly and stimulates the release of insulin in a short period of time, but too much insulin release will cause a drop in blood sugar, which makes us show a series of discomfort symptoms (such as sleepiness, mood swings, poor concentration, irritability, etc.), and then the body needs to eat more sugar to relieve these discomforts. Simple carbohydrates are mainly sugar, sweets, sweetened beverages, sweetened wine, foods made from refined carbohydrates, and many processed foods. Refined carbohydrates (white bread, white flour, white rice, etc.) lack beneficial fiber and nutrients. Complex carbohydrates are made of sugar molecules linked together, and their digestion process needs to be carried out under the action of specific enzymes, so their digestion and absorption time is significantly longer than that of simple carbohydrates. The blood sugar level will rise slowly after eating complex carbohydrates, and the process of releasing energy is also slow, so that the rate of blood sugar decline will be more moderate, thus avoiding the rapid fluctuation of blood sugar and not making people have the desire to eat sugar. Soy foods and fruits such as apples, pears, peaches and plums contain complex carbohydrates, as do starchy foods such as brown rice and whole wheat bread, and these foods also retain their original vitamins, minerals and nutrients such as fiber that are beneficial to the body.