If you are trying to lose extra weight, exercising on an empty stomach can help. You might think you need food to fuel your workouts, but you would be wrong. Recently, the advice to load up on carbohydrates before exercise has been called into question. Doing so inhibits the body from using stored energy (glycogen and body fat) for fuel. This results in less fat-burning benefits of exercise.
Over the course of the day, your body shifts back and forth from a fed and fasted state. The fed state lasts 4-6 hours after eating. During this time, your body releases insulin to shuttle glucose and amino acids released from food into your cells. Six hours after eating, you begin to enter a fasted state. Glucagon is released to prevent blood sugar from going too low. Also, the body begins to break down fat tissue into free fatty acids which can be converted by the liver into cellular fuel call ketones. You are literally burning fat for energy! As soon as start eating, this process is halted and the fat-burning is over.
The best time to exercise is at least 6 hours after you have eaten. When you first begin exercising on an empty stomach, your workouts will be more difficult than before. However, your body will quickly become more efficient as your muscle learn to use less glycogen and instead burn stored fat as fuel. To give an extra boost to your metabolism, drink some unsweetened green or black tea, or plain black coffee right before your workout. And, of course, always drink plenty of water before, during, and after exercise.
