Training Fasted: Does Exercising on an Empty Stomach Really Help You Burn More Fat?

The concept of fasted training has been a hot topic for years. The idea is simple: exercising on an empty stomach, typically after a night of fasting, can help your body burn more fat. Many people swear by it, claiming that they’ve seen faster fat loss results by skipping breakfast before hitting the gym. But does science back up these claims? In this blog, we’ll explore the pros and cons of training fasted, and help you decide if this approach is right for your fitness journey. 

What Is Fasted Training? 

Fasted training refers to training after an overnight fast or extended period without eating, typically before breakfast. Most people practice it after 8-12 hours of fasting. In this state, your body is low on readily available glucose (the sugar from food), and it turns to fat as its primary energy source. This has led many to believe that fasted training promotes fat loss by encouraging the body to burn more fat than when you eat beforehand. 

Does Fasted Training Actually Help You Burn More Fat? 

While it sounds promising, the evidence on whether fasted training leads to greater fat loss is mixed. 

1.  Short-Term Fat Burning - Some studies suggest that exercising on an empty stomach can increase fat oxidation during the workout. For example, a 2014 study found that individuals who performed exercise in a fasted state burned about 20% more fat than those who ate before working out. However, this does not necessarily translate into greater long-term fat loss. While you may burn more fat during the workout, the difference in overall fat loss over time is minimal when compared to exercising after eating. 

2.  Caloric Deficit Matters More - Ultimately, the key to fat loss isn’t necessarily when you train, but how many calories you burn versus how many you consume. A 2015 study concluded that while fasted exercise might increase fat burning in the short term, it doesn’t significantly affect fat loss over the long term. Creating a calorie deficit is far more important for fat loss than whether you train in a fasted state. 

3.  Exercise Type Matters - Another factor is the type of exercise you're doing. Fasted training might be beneficial for low- to moderate-intensity activities like walking, steady-state cardio, or light cycling. However, if you're doing high-intensity workouts like weightlifting or sprinting, your body relies more on glycogen for quick energy. Training in a fasted state could leave you feeling fatigued and less capable of performing at your best, which could negatively impact your workout and, ultimately, your progress. 

Pros of Fasted Training 

1.  Increased Fat Oxidation - As mentioned earlier, exercising on an empty stomach may help increase the amount of fat your body burns during the workout. This could be appealing if you’re focused on fat loss, especially if your primary goal is to shed fat while preserving muscle. 
2.  Convenience - If you prefer working out early in the morning and don’t have time for a full meal beforehand, fasted training can be a convenient option. You don’t have to wait for digestion, and it allows you to jump straight into your workout. 
3.  Improved Insulin Sensitivity - Some research suggests that fasting before exercise can improve insulin sensitivity, which can help with weight management and overall metabolic health. By reducing insulin levels, you may encourage your body to burn more fat for fuel. 

Cons of Fasted Training 

1.  Reduced Performance - If you're aiming for high-intensity or strength-based workouts, training without food can reduce your performance. Without adequate fuel, your body may struggle to lift heavy weights, complete sprints, or maintain endurance during intense sessions. 
2.  Muscle Loss Risk - Fasted training could potentially lead to muscle breakdown, especially if you’re doing intense or prolonged workouts. In a fasted state, your body might break down muscle tissue for energy if glycogen stores are low. This is why it's crucial to balance your training routine with proper nutrition to prevent muscle loss. 
3.  Increased Risk of Fatigue and Hunger - Some individuals may feel light-headed, weak, or excessively hungry during fasted training. This could negatively affect the quality of your workout and may make you more prone to overeating later in the day, potentially undoing any calorie-burning benefits. 

Should You Train Fasted? 

Ultimately, whether you should train fasted depends on your fitness goals, workout routine, and how your body responds to exercising on an empty stomach. If your primary goal is fat loss and you prefer doing steady-state cardio, fasted training might work for you. However, if you’re focused on strength training, building muscle, or doing high-intensity interval training (HIIT), it’s probably best to eat something before your workout to fuel your performance. 

Conclusion 

Exercising on an empty stomach can lead to increased fat oxidation during your workout, but it doesn’t guarantee greater fat loss in the long run. The key to fat loss is creating a consistent caloric deficit, regardless of whether you eat before your workout. Listen to your body, experiment with different approaches, and find out what works best for your lifestyle and fitness goals. At the end of the day, the most important thing is to stay consistent with your training, maintain a balanced diet, and make sure you’re fuelling your body properly for your specific needs.  

Written by Tom Weaver