Breakfast is the most important meal of the day…or is it?

Many people follow the motto “breakfast is the most important meal of the day”. On the other hand, intermittent fasting, which often involves deliberately skipping breakfast, is becoming increasingly popular. How does this fit together?

What, how much and when you should eat is a much-discussed topic with countless opinions. For example, who hasn't heard the saying: "Breakfast is the most important meal of the day"? Most people would perhaps attribute this to the wisdom and life experience of their grandparents, but this saying is actually an advertising slogan for Kellogg's breakfast cereal from 1917 [1].
At the same time, intermittent fasting is gaining popularity and is being touted as beneficial to health [2]. This is an eating regimen in which you limit your food intake to a predetermined time window, for example by skipping breakfast. But what is true? Do I have to eat breakfast to be healthy and productive?

This question has inspired several studies on the influence of breakfast on academic performance. A review article has summarized several of these studies [3]. The studies mostly investigated experimentally how well pupils performed on a morning when they had eaten breakfast compared to a morning when they had not. Overall, pupils were able to concentrate longer in the morning on days with breakfast than on days without breakfast. Performance losses on days without breakfast mainly affected attention, executive skills and memory. However, these effects were rather short-lived and particularly pronounced in pupils who received a less healthy diet at home. However, further research is needed to be able to transfer the results from the laboratory to everyday school life.
What is the situation in adults? Another review article summarized several studies on skipping breakfast in adult participants. Similar results were found here: study participants who ate breakfast showed slight advantages in their memory performance [4]. On the other hand, no clear effect on attention and executive abilities was found for adult participants. The authors also investigated whether what you eat for breakfast plays a role. However, there were not enough reliable studies on this to make a summarizing statement.
Even if some of the studies examined are only of limited significance, it can be assumed that eating breakfast can have – at least short-term – benefits. This association appears to be more far-reaching for schoolchildren than for adults.

These results can be interpreted in different ways. For example, the brain needs energy. It gets this from breakfast, among other things, and can therefore do its job. In addition, many people are used to eating their breakfast cereal in the morning. So, if participants are instructed to skip breakfast, this can be unfamiliar for many and be accompanied by a deterioration in mood [3]. This deterioration in mood – and not the lack of energy – could then lead to lower motivation and performance.
In summary, skipping breakfast can lead to a limited, short-term deterioration in cognitive performance for people who are used to eating breakfast. However, these results do not yet prove that breakfast is the most important meal of the day. The decision to eat breakfast or not should be made on an individual basis based on personal preferences, needs, or specific circumstances.



[1] Cooper, L. F. (1917). How to cut food costs. Good Health Publishing Company.

[2] Mattson, M. P. (2022). Intermittent Fasting Revolution: The science of optimizing health and enhancing performance. MIT PRESS.

[3] Adolphus, K., Lawton, C. L., Champ, C. L., & Dye, L. (2016). The Effects of Breakfast and Breakfast Composition on Cognition in Children and Adolescents: A Systematic Review. Advances in Nutrition, 7(3), 590-612.

[4] Galioto, R., & Spitznagel, M. B. (2016). The Effects of Breakfast and Breakfast Composition on Cognition in Adults. Advances in Nutrition, 7(3), 576-589.


Note: This article was already reviewed and is published in the German version of In-Mind.