FOOD IS MEDICINE
THE SCIENCE OF INTERMITTENT FASTING Navigating the balance between resting and replenishing nutrients for optimum health benefits. BY TAPP FRANCKE
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consumption of nutrient-rich whole foods. There are four styles of IF: 16-8: The baseline for fasting is 12 hours of fasting (including sleep) followed by an eating window of 12 hours. This does not mean eating for 12 hours straight! It refers to maintaining a normal diet in the 12 hours where eating is permitted. Working up to a 16-hour fasting period with an eight-hour eating window is recommended, as it allows for a longer amount of time in ketosis. 5 AND 2: This type of intermittent fasting entails eating a normal diet with no designated fasting periods for five days, and then spending two days a week eating only 500 calories per day. THE WARRIOR: Fasting with nothing but water for 24 hours, one day a week. 5-DAY FASTING MIMICKING: This diet limits carbohydrates and proteins, both of which can be turned into glucose, and focuses on a low level of fat-based foods for a period of five days. Having your body in ketosis for a five-day period allows your body to do the maximum amount of cellular repair. It is recommended by Dr. Valter Longo, creator of the ProLon system, that this style of diet be done once per month for three months every year. Tapp Francke is Purist’s Contributing Health Editor and the founder of STANDwellness.com.
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Intermittent fasting (IF) is not a diet as much as it is an eating style. Intermittent fasters wait anywhere from 12 to 48 hours between meals, with the idea of getting the body into a fasting state. Throughout history, we’ve always had periods of feast and famine. Our bodies are set up to do specific jobs in each state. In our current three-square-mealsa-day food culture, 24-hour grocery stores and food-delivery services, we spend While fasting, the all of our time in a state of body draws upon nutritional cellular abunstored fats for energy. dance; our bodies never get a chance to reset. Cellularly speaking, there are two autophagy. This process is unique to a roads a cell can take: fed or fasted. fasted state. Autophagy, a Greek word On the fed road, cells are in a period meaning “self-eating,” is a way for the of acquisition and accumulation. They body to clean up and eliminate damare taking in glucose and nutrients, aged cells. This can initiate molecular using what they need and storing changes in the body that improve the rest. Insulin and glucose are high. cellular repair and gene expression. Excess is stored for later: The body According to registered dietitian stockpiles all of the extra glucose in Felicia Stoler, autophagy is a critical the form of glycogen. A stored form cellular process for proper immune sysof carbohydrates, glycogen is tucked tem function and, possibly, longevity. away in tissues and the liver. In 2016, the Nobel Prize in Physiology or On the fasted road, the body draws Medicine was awarded to cellular biolupon stored fats and carbohydrates ogist Yoshinori Ohsumi for his work in for energy. It uses up glycogen in a identifying and observing this extraorprocess called glycolysis, and then dinary cellular phenomenon. consumes stored fat in a process It should be noted here that IF, called ketosis. Though glucose is the though very good for your body, body’s preferred fuel source, the body should not be taken to extremes. adapts pretty quickly to the transition Although ketosis can trigger cellular from using stored glucose to using cleanup, it can also cause celluketone bodies (or fats) for energy. lar death when incurred over long In ketosis, the body is able to go periods of time. The key with proper into a cellular recycling process called IF is to follow periods of fasting with
