It evokes mixed feelings, with both supporters and opponents. Does it have more advantages or disadvantages? Is it safe for everyone?
The negative effects of exercising on an empty stomach were discussed with us by our PE teacher in elementary school. This was later confirmed in high school when girls went berserk. weight loss. Fasting and exercise while fasting were said to be the best way to lose weight. The myth about fasting has been definitively debunked, while morning exercise still evokes mixed feelings. I asked experts to resolve the controversy.
To fully understand the problem, we need to understand what happens in our bodies during sleep. During this time, we use up most of our liver glycogen stores for digestive processes. During sleep, the liver nourishes almost all organs—except for the muscles, which have their own stores of muscle glycogen. Because muscles don't share their reserves with other organs, they have a small energy reserve immediately after waking, unlike the liver, which is almost completely depleted. This is, of course, the case when we consumed carbohydrates the previous day.
The situation is different when we're on a low-carb diet – in the morning, we lack glycogen in both the liver and muscles. What does this mean in practice? At first glance, it might seem that morning is the ideal time to train, because the body will draw energy from fat, and we're after fat loss. However, this is only part of the story. In reality, such training will be ineffective; without carbohydrates, we won't have adequate strength, and as a result, we'll overtax the body, deprived of energy resources.
However, let's assume we ensure adequate carbohydrate and protein intake the day before. Can we afford to train on an empty stomach? Which exercises should we perform and which should we avoid?
"To ensure safe training on an empty stomach, we should primarily avoid high-intensity exercises, such as sprints, strength training, or endurance training. Aerobic training, such as walking, running, or cycling, is a good option—anything at low or moderate intensity," explains Tomasz Gregorczyk, personal trainer for Get Slim Club.
The good news for fans of aerobic training is that it's effective and safe when done in moderation. It's important to remember that such a workout shouldn't be too long—ideally, limit it to 30-40 minutes.
- Prolonged exercise will cause the body to draw energy from the muscles instead of burning it and drawing it from fat tissue, leading to catabolism, i.e. the breakdown of muscle tissue - explains the trainer.
This opinion is also confirmed by a psychodietician.
Exercising on an empty stomach will only be safe and healthy if approached sensibly and in moderation. It's easy to overdo it, and instead of getting in shape, you could burn muscle.A short, 25-35 minute set of low intensity, performed within an hour of waking up, will certainly not do any harm - says Agnieszka Owczarek, psycho-dietitian, brand expert Noble Health.
I can't imagine leaving the house without breakfast - it's my favorite meal of the day. However, I know people who don't start eating anything until around noon, even though they start their day at 7-8 a.m. This isn't the best solution for many reasons - skipping breakfast contributes m.in. to slowing down the metabolism. If someone fasts for a long time, does this give them more time for a morning workout? Does it matter?
"After waking up, we need to prepare our body for the intended physical activity. First, we take care of our physiological needs. Then, before we begin our workout, we do a light warm-up. It's best to start within an hour of waking up," explains Patrycja Malik, a personal trainer at Get Slim Club.
The trainer also emphasizes that the number of fasted workouts should be controlled. To achieve this, it's worth first determining what you want to achieve through exercise. Are you looking to lose fat, or perhaps build strength and fitness?
"If we want to get rid of body fat, fasted workouts can be performed even daily, but if we dream of an athletic physique, i.e., when we focus on strength, muscle mass, and endurance, we should avoid fasted activity," he adds. "Frequent fasted workouts involve a large dose of training, which draws enormous amounts of energy from the body and quickly tires the body, so they are only possible with a healthy lifestyle and a balanced diet - he emphasizes.
Considering the positive and negative effects of fasted training, it turns out that it has as many disadvantages as advantages. By trying to burn fat more effectively in the morning, we expose our bodies to weakening. Therefore, it's important to ensure a well-balanced diet when training at dawn. When deciding to engage in physical activity on an empty stomach, it's also worth considering the goal.
"If fat burning is your top priority because you're significantly overweight, and fitness is your second priority, then fasted exercise will be suitable for you. However, if fitness and fat burning are equally important to you, I recommend eating a light meal (around 250-300 kcal). This will give you more energy for a longer workout," concludes Agnieszka Owczarek.
