The truth about running on an empty stomach

Running on an empty stomach – yes or no?

There are many different opinions on this topic. For some this is a regular part of training, while for others training on an empty stomach is excluded. In today’s blog post, we will look at the three biggest myths and show you the truth behind them.

1. “Training on an empty stomach leads to muscle loss”

The general opinion in the gym is that training without breakfast leads to muscle loss. But don’t worry, your muscles won’t disappear right away.

It is often mistakenly assumed that without food the body lacks the necessary carbohydrates and glucose (sugar) for training in the morning. According to this view, the body is forced to break down muscle protein to get the energy it needs.

In other words, the body loses muscle. But this is not exactly 100% accurate: the body stores glucose in the form of glycogen (stored form of sugar) in the liver and muscles. At night, the levels of insulin in the body (which helps cells absorb sugar and inhibit fat loss) and liver glycogen decrease. But the body still has stores of muscle glycogen. So when you start your morning run, your body initially gets its energy from the glycogen stored in your muscles.

But as your workout continues, your glycogen stores – or just carbs – are virtually depleted. Therefore, your body is forced to find a different supply of energy and increasingly resorts to free fatty acids for fuel.

If you now increase the intensity of your workout, your body will also get the energy it needs by breaking down proteins (ie amino acids) to compensate for the lack of glycogen and the insufficient supply of energy from fats. Only then do you risk losing muscle. However, most runners have already stopped training by this time, as the huge lack of glycogen is usually accompanied by symptoms such as dizziness, weakness and fatigue.

2. “Running on an empty stomach is the best method to lose weight”

Training on an empty stomach is often advertised as the best way to burn fat and lose weight. While it is true that running on an empty stomach, if done the right way, can eventually force your body to get more and more of the energy it needs from free fatty acids, this is not the deciding factor in losing weight.

The percentage of energy produced by burning fat is quite high, but the total energy expenditure (TEE) and therefore calorie consumption are relatively low due to the low intensity of training. In the case of a high-intensity running session, such as interval training, the percentage of energy produced by burning fat is significantly lower. However, TEE and calorie consumption are many times higher. At the end of the day, the most important thing in losing weight is the energy balance: if you burn more calories than you consume, you lose weight. That’s why high-intensity running sessions are preferable to running on an empty stomach when it comes to losing weight.

3. “Running on an empty stomach increases your endurance”

Training on an empty stomach is not a good idea for hobby athletes who want to improve their performance. The duration and intensity of training are severely limited by the lack of glycogen. Therefore, the predicted training incentive is quite low. A high-quality workout that lasts longer and with a higher intensity is better for improving your performance.

Research on professional athletes shows that many positive effects can be achieved through specific training with pre-emptied glycogen stores. This causes your body to optimize and save its fat metabolism. The body learns to deal longer with the glycogen stored in the muscles. However, there is no substantial evidence to suggest that this leads to improved race performance. At the same time, it is important to note that regular exercise with pre-emptied glycogen stores can adversely affect your health.

Even if there are more effective methods to lose weight or improve endurance, running on an empty stomach can add the desired variety to your workout. This type of training is especially suitable for morning people who want to train before breakfast.

So, if you want to run on an empty stomach, here’s what we recommend:

• Depending on your fitness level, your run should last between 40 and 60 minutes.
• Choose low intensity (when running for recovery or pace of conversation).
• You should drink a glass of water before running.

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