Whether you’re fasting or not, your body still needs energy. The body’s main source of energy is a sugar called glucose, which is usually found in carbohydrates, including grains, dairy products, fruits, some vegetables, beans, and even sweets. The liver and muscles store glucose and release it into the bloodstream whenever the body needs it.

However, during fasting, this process changes. After about eight hours of fasting, the liver will use up the last of its glucose stores. At this point, the body enters a state called gluconeogenesis, which marks the transition of the body to a fasting state. Studies have shown that gluconeogenesis increases the number of calories the body burns. If carbohydrates are not consumed, the body begins to produce glucose using fat.

Eventually, these energy sources are used up by the body, and if fasting continues, it can turn into a more serious starvation. At this stage, the metabolism slows down considerably and the body begins to burn muscle tissue for energy. True starvation occurs after several consecutive days or even weeks without eating; therefore, since fasting in Islam is less than 24 hours, it is generally safe and will not cause any problems for you unless you have a specific disease, and it also has some benefits.