No simply a myth. If you do not eat before you train/exercise, you decrease your body’s ability to maximize fat burning.
The Myth: Working out first thing in the morning on an empty stomach will maximize fat burning, since muscle glycogen (stored carbohydrate) is low, which is the preferred fuel source for muscles. 1st,let’s remember that at least 8 to12 hours may pass between dinner or an evening snack until waking, meaning energy levels are at their lowest upon waking or after a long break between meals. 2nd, exercise itself does not burn a great amount of fat no matter how long the activity. It is the contribution of exercise to a person’s total daily energy expenditure (TDEE), including the intensity, that affects fat loss. In other words, exercise simply adds to your daily calorie needs, and as long as you don’t consume more to compensate (keeping your intake below your needs) the body must draw on its fat stores and you’ll lose fat throughout the entire day. So if you properly eat before exercise, you have the potential to perform better, enhance recovery and burn more calories.
The higher the intensity of your workout (which you can now perform thanks to having filled your energy stores with a pre-workout snack), the more calories from fat you will use throughout the day. The energy or calorie deficit, not the workout or when you eat, determines how much weight/fat you lose. We’re not suggesting you add calories to your daily intake. Simply adjust the way you distribute your total allowed calories (based on goal) throughout the day. Spacing meals properly has added benefits, such as using more calories to digest each meal (after a meal the body has work to do in digesting and absorbing food), and a steady stream of nutrition (enhancing recovery and energy) as well as controlling hunger.