How Does the Body Burn Fat While Fasting?

1. 

   Fasting

   • The definition of fasting varies greatly. The most extreme form of fasting is not allowing anything except water to pass your lips for 12 to 24 hours, or even longer. A looser definition is not eating solid foods and only consuming protein drinks or juices. In order for the body to begin to burn fat while fasting, it needs to enter into a state called ketosis. Ketosis occurs when the body has used up its glycogen supply and needs more energy. It turns to protein sources such as lean muscle mass and starts breaking the protein into amino acids and then into glucose that can be used by the body.
     

   Burning Fat

   • Normal bodily functions use glucose as an energy source, and the human brain requires glucose in order to function. While fasting, energy sources are not provided through food intake. Your body turns to its glycogen reserve. Glycogen is stored in your liver and is converted into glucose during the initial stages of fasting. Once the body's glycogen supply has been used, it looks to other sources for glucose. As mentioned earlier, your body is able to convert protein into glucose. However, your body also wants to protect its protein supply, so it begins the process called ketosis so that your body does not quickly deplete its protein supply. Ketosis converts the body's fat into ketones, which can be used as an energy source. Induced ketosis occurs when a person's intake of carbohydrates are severely restricted. Ketosis takes place during a total fast. If a fast is supplemented with juice drinks, which are high in carbohydrates, the body will first use any available carbohydrate for energy and normal cell function. High-protein, low-carbohydrate diets also induce ketosis.
     

   Intermittent Fasting

   • Intermittent fasting, which limits food intake for a number of hours or parts of days, might have other health benefits. A study done at the University of Utah on 448 individuals, showed that intermittent fasting lowered the risk of heart disease and the prevalence of diabetes. Results of this study were published in the October 2008 American Journal of Cardiology. Consult your doctor if you are interested in fasting or reducing calories to burn fat and lose weight. Your doctor might send you to a nutritionist who will help you assess your dietary and caloric needs to recommend a healthful diet.