Running on an empty stomach... good or not?
Exercising on an empty stomach, particularly for runners and cyclists, is gaining increasing interest. Whether you're an endurance enthusiast or a casual athlete looking to improve your performance, you've probably heard of what's called "fasted training." But is this technique really effective? What are its real benefits, and what are the associated risks?
What is fasted training?
Fasted training involves engaging in physical activity without eating a solid meal beforehand, usually after a prolonged period of fasting, such as a night's sleep. The body then begins exercise with reduced glycogen stores, prompting it to rely more on fat for energy.
Who is this practice suitable for?
Fasted training is primarily aimed at endurance athletes (such as marathon runners or ultra-distance cyclists), but it can also be suitable for anyone looking to explore better energy management. However, it is not recommended for beginners or athletes with specific health conditions (such as diabetes).
The Benefits of Fasted Training
1. Increased fat oxidation
When the body is depleted of glycogen, it learns to better use fatty acids as fuel to support exercise. This is particularly useful for endurance sports where better management of energy reserves is crucial.
2. Metabolic sensitization
Training in a fasted state can improve metabolic flexibility, which is the body's ability to quickly switch from one energy source (such as glucose) to another (such as fat), which is key in prolonged efforts.
3. Fat loss
By relying more on fat as their primary fuel, some exercisers observe a reduction in their body fat.
4. Optimization of muscle adaptation
According to some studies, fasted training may improve enzymatic mechanisms involved in muscular endurance, such as mitochondrial biogenesis.
Pitfalls and precautions to take
While fasted training has some interesting benefits, it's not without risks. Here are some things to watch out for:
1. Reduced performance in intensive sessions
Without sufficient glycogen, your ability to perform maximum efforts (such as sprints or HIIT) will be reduced. This type of training is therefore best suited to moderate-paced sessions.
2. Risk of excessive fatigue
Poorly planned fasted training can lead to significant fatigue and even overtraining.
3. Muscle loss
In the absence of carbohydrates, the body may break down muscle protein for energy, which can be counterproductive to athletic goals.
4. Hypoglycemia and malaise
Sensitive people may experience dizziness or drops in blood sugar. It's important to listen to your body.
5. Poor adaptation for beginners
If you are new to the world of exercise or do not have a well-established routine, starting with fasted workouts is not recommended.
How to Optimize Your Fasted Workouts?
To get the most out of this method without compromising your health, follow these tips:
1. Plan your sessions
Choose moderate workouts lasting less than 60 minutes to avoid completely depleting your reserves.
2. Hydrate properly
Without a meal beforehand, your hydration becomes a priority. Use electrolyte-rich solutions, like RYD-01 , to avoid mineral imbalances related to sweating.
3. Add carbohydrates if needed
If your workout exceeds 90 minutes or becomes intense, consider adding a small amount of fast-acting carbohydrates, such as gels or light energy drinks.
4. Listen to your body
Excessive fatigue, dizziness, or an inability to maintain your effort are warning signs. In this case, stop training and opt for a snack.
Fasted Run: One Tool Among Others
While fasted training can be a valuable asset in your athletic preparation, it shouldn't be a one-time or systematic practice. Alternate with fasted sessions to maximize your performance and ensure your nutritional needs are always met.
In conclusion, like any technique, fasted training must be well understood and used thoughtfully. Respect your body's signals and remember that the key to success lies in balance.
Sources:
“Effects of Fasted vs Fed-State Exercise on Performance and Metabolism” - Journal of Sports Science & Medicine, 2021
“The Impact of Fasted Training on Endurance and Adaptation” - International Journal of Sports Nutrition, 2020
“Fasted Running Benefits and Risks” - American Journal of Physiology, 2019
Recommended website: TrainingPeaks - Fasted Training
Book: "Endurance Sports Nutrition" by Suzanne Girard Eberle
