The Obesity Code: Unlocking the Secrets of Weight Loss (Why Intermittent Fasting Is the Key to Controlling Your Weight)

by Jason Fung

THE HUMAN BODY is characterized by the fundamental biological principle of homeostasis. If things change in one direction, the body reacts by changing in the opposite direction to return closer to its original state. For instance, if we become very cold, the body adapts by increasing body-heat generation. If we become very hot, the body sweats to try to cool itself. Adaptability is a prerequisite for survival and generally holds true for all biological systems. In other words, the body develops resistance. The body resists change out of its comfort range by adapting to it. What happens in the case of insulin resistance? As discussed before, a hormone acts on a cell as a key that fits into a lock. When insulin (the key) no longer fits into the receptor (the lock), the cell is called insulin resistant. Because the fit is poor, the door does not open fully. As a result, less glucose enters. The cell senses that there is too little glucose inside. Instead, glucose is piling up outside the door. Starved for glucose, the cell demands more. To compensate, the body produces extra keys (insulin). The fit is still poor, but more doors are opened, allowing a normal amount of glucose to enter. Suppose that in the normal situation we produce ten keys (insulin). Each key opens a locked door that lets two glucose molecules inside. With ten keys, twenty glucose molecules enter the cell. Under conditions of resistance, the key does not fully open the locked door. Only one glucose molecule ...