Can You Train Without Breakfast?

Some trainers prefer to exercise in the morning as it is often the only free time they have to achieve their training goals. However, there may be situations where it is not possible to eat breakfast before training. Is a meal before morning exercise mandatory? Scientists decided to investigate this by conducting an experiment on 16 participants who were randomly given a high-carbohydrate breakfast (> 100 g) or plain water. After 2 hours, the participants in the experiment performed the planned training, which consisted of 4 sets of bench press and squats until muscle failure (10RM). It turned out that those who had breakfast performed 10 more repetitions in squats and 3 more in bench press (Naharudin et al., 2019). However, the scientists also decided to investigate the effect of the placebo effect on the results of individuals who did not eat breakfast before training. The participants were divided into three groups: the first received water, the second received placebo, and the third received carbohydrates. The experiment used "gels" made of xanthan gum and carbohydrates or xanthan gum and water. After analyzing the results, it turned out that the difference in the achieved results between the group that consumed carbohydrates and the group that consumed water was similar. As for the group that consumed placebo, the participants in the experiment achieved comparable results to those who had eaten a carbohydrate-rich breakfast (Naharudin et al., 2020). It can therefore be assumed that the effectiveness of training without breakfast depends on whether hunger is noticeable and to what extent, and also on the attitude of the trainer. However, it should be noted that the participants in the mentioned studies regularly ate breakfast, which could affect their results.

In 2018, a meta-analysis was conducted to evaluate the effects of fasting exercises on sports achievements. It was found that performing training sessions without consuming food can negatively affect the achieved results, especially during prolonged efforts. Furthermore, if our energy access is limited, our body's immune system may weaken, increasing the risk of diseases (T. P. Aird, R. W. Davies, B. P. Carson 2018). Therefore, the decision to train in a fasted state, especially for athletes, should be made carefully. Those aiming for better results may consider conducting training sessions after a meal.

Both the energy expended during physical activity and the energy supplied with meals influence the total energy balance.. Researchers decided to investigate whether carrying out cardio training in a state of hunger affects the regulation of hunger and the number of consumed calories.. The study involved 12 young, athletic women.. The participants performed the training before breakfast and after the meal.. Then, on one day, they consumed as many calories as they wanted.. It turned out that the subjects consumed about 400 kcal more on days with training after the meal than on days with training in a state of hunger (R.. E. Edinburgh et al. 2019). In a study with a group of trained men, scientists came to similar conclusions.. The participants performed planned training sessions both before and after breakfast and then ate as many calories as they wanted.. After 24 hours, the researchers found that the subjects who trained before breakfast delivered 20% fewer calories to the body than those who trained after breakfast (J.. L. Bachman, R. W. Deitrick, A. R. Hillman 2018). On the first glance, it seems that training in a state of hunger might be a helpful method for reducing fat tissue. Unfortunately, the mentioned studies only monitored the consumed calories within 24 hours and there is a lack of information about whether the effect lasts long-term.

Taking into account the current state of knowledge, there are no significant arguments against performing exercises during fasting, which do not contribute to better results in either building muscle mass or reducing body fat. Individuals who prefer fasting training or are unable to plan post-meal training for various reasons can continue their training objectives without reservations. However, if our primary goal is to achieve athletic success, it is more advantageous to take a small portion of carbohydrates to training, as they are able to provide the necessary amount of energy.