can fasting exercise help reduce fat

Some say that exercising on an empty stomach can help you burn more fat and is more effective for weight loss. Is this really the case? In this episode of 'Unexpectedly,' we will discuss this topic with you.Why exercising on an empty stomach does more harm than good.

It's time for your daily workout. Should you eat something first, or wait until after exercising? Advocates of fasting exercise, and even some who promote hunger workouts, will tell you not to eat first, claiming it can accelerate weight loss. Indeed, the British Journal of Nutrition once published a study showing that people who exercise on an empty stomach burn 20% more fat than those who are full. Another study published in the International Journal of Sport Nutrition and Exercise Metabolism found similar results: aerobic exercise in a fasted state reduces body fat percentage more effectively.

Why does it burn more fat? It's because your body is switching its energy source. To complete high-intensity workouts, like long-distance running or weightlifting, your body needs to burn glycogen (stored carbohydrates). If your body depletes its glycogen reserves (such as when you're hungry or dieting), it needs to use another substance for energy, which in this case is fat.

However, losing weight on an empty stomach is not as simple as it seems. First, your body is naturally not accustomed to hunger and will instinctively want to store fat. When you burn fat quickly, your body will alter your metabolism to compensate for the significant fat loss. In other words, your body will enter a survival mode and start burning fewer calories. So, after burning this extra fat, when you eat your next meal, your body will signal you to consume more to gain more energy. Thus, you will completely offset the benefits of fasting for fat loss. The American Journal of Clinical Nutrition also found that prolonged fasting can lower metabolic rates, counteracting fat loss.

Eating before exercise can also suppress your appetite. Studies show that those who exercise on a full stomach have less desire to eat afterward compared to those who exercise on an empty stomach. Weight loss largely depends not on what you do but on what you eat, so appetite control is crucial.

Additionally, in some cases, exercising on an empty stomach can lead to muscle loss. If you've burned through all your glycogen reserves, your body will break down muscle protein for the needed energy. High-intensity training causes muscle fibers to tear, and your body uses protein synthesis to build stronger muscles. Fasting exercise breaks down more muscle, making muscle building more difficult.

This sounds quite alarming, but it only happens when you increase the intensity of your training. If the first thing you do in the morning is your daily workout without eating, your muscles might still have glycogen reserves from last night's dinner. Essentially, as long as you don't overtrain, fasting won't cause you to lose too much muscle.

This brings up another issue: although you can exercise on an empty stomach without worrying about muscle loss, you won't have the energy to increase your training intensity. Those who exercise on a full stomach can push themselves to persist and gradually increase intensity for qualitative changes. Therefore, fasting training will severely limit your athletic performance and affect your ability to set personal bests.

Although exercising on an empty stomach is an acceptable method—some people enjoy the light feeling, which makes their bodies more agile and their focus sharper—there don't seem to be any substantial benefits beyond personal preference. We recommend consuming carbohydrate-rich foods an hour before exercise and high-protein, low-carb foods after exercise. Additionally, not eating can put you in a bad mood, and no one wants to see a grumpy person at the gym, right? Push your body a bit to gain a refreshed mindset, rather than feeling hungry and miserable, only to binge eat after training to vent.