Brain fog at work: A message to all the breakfast-skippers

Just like every morning, you hear your alarm going off, and crawl further underneath your warm and fuzzy blanket, thinking “just five more minutes.” But when five minutes turn into ten and ten turn into half an hour, your breakfast plan slowly shrinks from eggs with avocado toast, fruit salad, and iced coffee to just toast with black coffee. And when you finally get up, you realize there’s not even enough time for breakfast anymore. In a rush, you grab your laptop and phone, brush your teeth, and take off. On the way to work, you grab a coffee to-go and finally arrive at work, happy and awake thanks to caffeine for breakfast.


Skipping meals, such as breakfast, intentionally or unintentionally may be regarded as intermittent fasting (Santos et al., 2022), a strategy that is hotly debated among researchers, healthcare professionals, and the general public (VOA Learning English, 2020). Intermittent fasting is an umbrella term, being only vaguely defined, including several different techniques. Most commonly it refers to not eating for at least 12 hours a day and allowing normal food intake for the rest of the day (Santos et al., 2022).


“Skipping meals, such as breakfast, intentionally or unintentionally may be regarded as intermittent fasting (Santos et al., 2022)”.


On social media intermittent fasting has gained increasing attention and promises being a key to weight loss (VOA Learning English, 2020). Research has confirmed some, but by far not all, of the promised health benefits. For example, studies have shown an association between intermittent fasting and longer life expectancies (Longo et al., 2021), a promotion of weight loss, and a reduction in inflammatory processes (Song & Kim, 2023). In addition, a review article indicated that findings from animal studies evidenced mechanisms by which Parkinson’s disease, ischemic stroke, autism spectrum disorder, mood, and anxiety disorders could benefit from intermittent fasting (Gudden et al., 2021). Nevertheless, the same review article (Gudden et al., 2021) suggested the absence of clear evidence of a positive short-term effect of reduced calorie intake on brain and cognitive function. Therefore, the evidence suggests potential benefits for specific conditions but it seems to be a highly controversial topic. 


Feed your performance!

Your brain needs energy to perform its functions, in the form of food. Approximately 20% of the calories we consume are utilized by the brain to enable processes such as thinking, paying attention, or remembering a list of groceries (Richardson, 2019). If we skip meals or engage in fasting, these processes can suffer, and our cognitive performance can decrease. Benau et al. (2014) summarized several studies assessing the effects of fasting on facets of cognitive performance. They note that the results are contradictory but some studies have shown that skipping breakfast may negatively impact the ability to recall words that were learned previously (Sünram-Lea et al., 2001, as cited in Benau et al., 2014). Furthermore, the review noted that intermittent fasting may slow down processing speed (Green et al., 1997; Doniger et al., 2006, as cited in, Benau et al., 2014). Participants in these studies showed slower reaction times as well as accuracy in moderately difficult exercises. All in all, verbal short-term memory as well as your processing speed can suffer when you engage in intermittent fasting.


“Verbal short-term memory as well as your processing speed can suffer when you engage in intermittent fasting”. 

Feed your smile!

According to the Australian Centre of Clinical Interventions (2018), semi-starvation –which refers to regularly restricting calorie intake leading to a survival adaptation due to reduced energy intake– has detrimental effects on all areas of your life. Besides cognitive effects like a decrease in concentration and problem-solving abilities, changes in mood, well-being, and health are observed. Physiological effects like headaches and greater fatigue were measured following semi-starvation. Additionally, it seems to be a link to reduced energy intake and mood fluctuations, intense emotions, anxiety, depression, decreased enthusiasm, and motivation. Semi-starvation and intermittent fasting differ in the sense that intermittent fasting does not require a decrease in total calorie consumption over the course of one day. However, engaging in intermittent fasting is also associated with a decrease in calorie consumption (Song & Kim, 2023) and may therefore, if performed on a regular basis, elicit similar effects on one’s mental health as semi-starvation. 

Stevenson and Francis (2023) further explained that, according to the animal and human energy restriction literature, while small mammals have been shown to extend their lifespan through energy restriction, the evidence for beneficial effects on primates and humans is equivocal, or at least, not clear enough. 

Overall, your mental and overall well-being can suffer significantly if you engage in extreme forms of intermittent fasting, caloric restriction, or skip meals often. 


“We first make our habits, then our habits make us” John Dryden (1903) 

Skipping breakfast regularly is worse than skipping breakfast once. A study has shown that skipping breakfast is associated with an increased risk of developing type 2 diabetes (Ballon et al., 2019). Type 2 diabetes is a condition in which people are resistant to insulin, and as a consequence, their body is unable to utilize the eaten food. Treatment is necessary. In the study skipping breakfast 4-5 times a week was associated with a 55% increase in the risk of developing type 2 diabetes. 


“Skipping breakfast regularly is worse than skipping breakfast once”.

Make breakfast a priority!

It is pointless to ignore the health benefits that fasting may offer to some individuals. Nevertheless, it is important to keep the negative effects in mind when you find yourself skipping meals regularly or intend to engage in fasting. Your brain and its functions depend on the energy we consume. Failing to fuel it sufficiently can negatively impact almost all areas of your well-being. Consequences are diminished cognitive performance, mood changes, and worsened health. The more often you engage in fasting, the more harmful these effects can be. Next time you find yourself snuggled in your blanket instead of preparing breakfast in the kitchen, remember: “Rather be a cereal killer than a breakfast skipper!”




Ballon, A., Neuenschwander, M., & Schlesinger, S. (2019b). Breakfast Skipping Is Associated with Increased Risk of Type 2 Diabetes among Adults: A Systematic Review and Meta-Analysis of Prospective Cohort Studies. Journal of Nutrition149(1), 106–113.

Benau, E. M., Orloff, N., Janke, E. A., Serpell, L. & Timko, C. A. (2014). A systematic review of the effects of experimental fasting on cognitionAppetite77, 52–61.

Centre for Clinical Interventions. (2018). What is starvation syndrome? Government of Western Australia.

Gudden, J., Vasquez, A. A., & Bloemendaal, M. (2021). The Effects of Intermittent Fasting on Brain and Cognitive Function. Nutrients, 13(9).

Longo, V. D., Di Tano, M., Mattson, M. P., & Guidi, N. (2021a). Intermittent and periodic fasting, longevity and disease. Nature Aging, 1(1), 47–59.


Richardson, M. W. (2019, 1. February). How Much Energy Does the Brain Use?

Santos, H. O., Genario, R., Tinsley, G. M., Ribeiro, P., Carteri, R. B., De Faria Coelho-Ravagnani, C., & Mota, J. F. (2022a). A scoping review of intermittent fasting, chronobiology, and metabolism. The American Journal of Clinical Nutrition, 115(4), 991–1004.

Song, D., & Kim, Y. W. (2023a). Beneficial effects of intermittent fasting: a narrative review. Journal of Yeungnam Medical Science, 40(1), 4–11.

Stevenson, R., & Francis, H. (2023). Starvation and Caloric Restriction in Adults. In Diet Impacts on Brain and Mind (pp. 250-306). Cambridge: Cambridge University Press. doi:10.1017/9781108755399.009

VOA Learning English. (2020a, January 15). New diet trend in America: intermittent fasting. VOA.


Note: Featured image by Matuska

Psychology Student

Isabel is a honours college psychology student. She has always been interested in the development of mental disorders and began studying psychology in 2021. Through the program, her interests have progressed, and she is now mainly interested in the study of psychological neuroscience, neuroendocrinology, and behavioral neuroscience. Further areas of interest concern eating and sleeping behaviors, psychological disorders, and biological psychology.

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  • Dennis Lutgert September 25, 2023'

    Nice work! I think a fair comment to make regarding breakfast culture is that non-dutch breakfast alternatives in Groningen tend be quite expensive. Healthy breakfasts require planning if made in advance or a lot of time when done early in the morning. Sure, whenever you truly feel like it, you can look up the healthy meal alternatives made quickly. I have days where I completely skip eating at all for a plethora of reasons not named here:

    1. If you’re already depressed due to no reason in particular (even the reasons named here), chances are you’re not inclined to eat
    2. If you’re raised with a sense of sharing meals or eating collectively, student life in appartments or the phase post-studying living on your own is not encouraging you to eat.
    3. There’s a good chance the majority of students are skipping breakfast because they just can’t afford it or feel like they should be spending relatively more money on dinner instead. This is why to me it is ironic to find this article in the newsletter by the faculty of behavioral sciences; it seems like Uni of Groningen forgot that because they do not house people but still allow them to study here, housing becomes completely unaffordable. You’re going to have to save on something, if you want a roof over your head. So telling me to eat more healthily as it’s important to have a more efficient day seems like a shared responsibility at least in the part that I should be able to take care of the minimum requirements to do so. That’s not the case.

  • Eric Rietzschel October 11, 2023  

    Hi Dennis, Mindwise is not actually a “newsletter by the faculty of behavioral sciences”; it is a science communication platform, and as such publishes contributions about a wide variety of topics from a wide variety of perspectives. Apart from that, it is indeed unfortunate that many students have financial problems, especially if this means they feel unable to make healthy life choices. Whether this can be blamed on the RUG not acting as a landlord is another discussion, which perhaps is best left to the pages of the UK. 😉

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