Does Running Fasted Burn More Fat

Running fasted has become a popular topic in the fitness world, with many athletes and fitness enthusiasts claiming that it can help burn more fat. But does running fasted really make a significant difference when it comes to fat burning? As an avid runner myself, I decided to delve into the research and share my personal insights on this matter.

The Science Behind Running Fasted

Running fasted refers to exercising on an empty stomach, typically in the morning before consuming any food. The idea behind this practice is that when your body is in a fasted state, it has depleted its glycogen stores and will rely more on stored fat for fuel during exercise.

During exercise, our body primarily uses two sources of energy: glycogen and fat. Glycogen is the stored form of carbohydrates in our muscles and liver, while fat is stored in adipose tissue. When we consume food, our body breaks down carbohydrates into glucose, which is then stored as glycogen in our muscles and liver. When we exercise, our body first utilizes the readily available glycogen for energy before tapping into the fat stores.

Advocates of running fasted argue that since glycogen stores are already depleted in the morning, the body will shift to burning fat for fuel at a higher rate than if you were to exercise after consuming a meal.

The Research and Different Perspectives

While some small studies have shown that running fasted may increase fat oxidation during exercise, the overall consensus is not so straightforward. The relationship between fasted exercise and fat burning is influenced by various factors such as the duration and intensity of the exercise, individual metabolism, and overall caloric balance.

One study published in the American Journal of Clinical Nutrition found that exercising in a fasted state did not result in significantly higher fat oxidation compared to exercising after a meal. The researchers concluded that the total amount of fat burned during exercise was more important than the percentage of fat burned.

On the other hand, a study published in The Journal of Sports Medicine and Physical Fitness showed that running fasted led to a higher rate of fat burning during exercise. However, this study had a small sample size and participants were only exercising at a low intensity.

It’s important to note that running fasted may not be suitable for everyone. Some individuals may experience low energy levels, dizziness, or performance decline when exercising on an empty stomach. Each person’s metabolism and response to fasted exercise can vary, so it’s crucial to listen to your body and make adjustments accordingly.

My Personal Experience

As someone who enjoys early morning runs, I have experimented with running fasted on several occasions. Personally, I find that running fasted works well for shorter, low-intensity runs. It gives me a sense of lightness and a clear mind, and I don’t experience any discomfort or energy crashes.

However, when it comes to longer or more intense runs, I prefer to have a light snack or a small meal before hitting the pavement. I find that having some fuel in my system helps me sustain my energy levels and perform better during the workout.


So, does running fasted burn more fat? The answer is not a straightforward yes or no. While there is some evidence to suggest that running fasted may increase fat burning during exercise, this effect may not be significant enough to outweigh other factors such as overall caloric balance and individual metabolism.

If you enjoy running fasted and it works well for you, then by all means continue doing so. However, if you find that it negatively impacts your energy levels or performance, it may be beneficial to have a small meal or snack before your workouts. Ultimately, it’s important to prioritize your overall nutrition, listen to your body, and find a routine that works best for you.