When we enter the fasted state, the body changes engines. It goes from burning glycogen and glucose as its main fuel sources and begins to favor fat for energy via a process called lipolysis. Lipolysis is the breakdown of stored fat into free fatty acids.
More free fatty acids means decreased glucose oxidation and the body begins to use fat for fuel. As you burn your own body fat in this process, hunger dissipates and you have more energy.
You also begin generating an alternative energy substrate called ketones. Ketones generate more energy than glucose with fewer by-products (e.g. free radicals). Ketosis is a state, not a diet, where the body uses ketones as its primary source of energy. This can be a result of fasting, a low carbohydrate diet, and/or exercise. * The Ketogenic diet is a therapeutic diet recommended for Alzheimer’s, Epilepsy, and cancer.
The benefit of Intermittent Fasting is that it allows us to utilize both our metabolic engines – fat burning and glucose burning. As we toggle between the two engines we get to be more metabolically flexible. You can cycle in and out of ketosis through fasting while also enjoying carbohydrates that aid in better sleep and mood (often a chief complaint of the ketogenic diet).