Getting a Handle on Hanger
Hunger and the Brain
Hanger begins in the body. When we haven’t eaten for a while, blood glucose levels drop. Glucose – derived from the food we eat – is the brain’s primary source of energy (Benton & Parker, 1998). Unlike other organs, the brain can’t store glucose for later use, so when levels dip, it sends out distress signals to let us know that it’s time to restore balance.
The hypothalamus, a small but vital region deep in the brain, monitors energy balance and helps regulate hunger, thirst, and emotion. When glucose levels fall, the hypothalamus releases hormones such as ghrelin, which triggers hunger, and activates stress-related pathways involving cortisol and adrenaline (Müller et al., 2015). These chemical changes heighten arousal (and irritability), preparing the body to seek food – an evolutionary adaptation to motivate survival.
Simply, when you’re hungry, your system is on alert - focused on getting food, not on being patient or polite. The physiological needs are hoisted up the list of priorities.
This physiological reaction supports an important idea by pioneering neuroscientist Lisa Feldman Barrett, whose Theory of Constructed Emotion proposes that emotions are not hardwired reactions, but dynamic interpretations of bodily sensations (Barrett, 2017). According to Barrett, your brain is in a constant state of prediction. When you feel the discomfort of low blood sugar, your brain interprets those signals in context. Your cognitive mind attempts to make sense of the situation. If you are stuck in traffic or having a stressful day, it may interpret that internal discomfort as anger – after all, your brain is not only processing the physical discomfort of hunger, but layering meaning on top of it. The interplay of physical state and psychological processing is where meaning is made. The hungry person is just trying to make sense of their sensations.
Easier said than done.
The Biochemistry of Irritability
Several studies have examined how hunger alters emotional regulation. A 2018 study published in Emotion found that people who were hungry were more likely to interpret ambiguous images as negative and report higher levels of irritability (MacCormack & Lindquist, 2018). This suggests that hunger biases perception and emotional interpretation. In other words, it might make the world seem more frustrating than it really is.
The culprit, in part, is the hormone cortisol. When blood sugar drops, cortisol and adrenaline are released to help free stored energy from the body’s reserves. These hormones increase alertness and drive, but they also elevate tension and impulsivity. Over time, or in moments of intense hunger, this can impact the brain’s capacity for self-control.
The prefrontal cortex – the region responsible for decision-making, empathy, and emotional regulation – depends on steady glucose levels to function optimally (Gailliot et al., 2007). When energy levels drop, this part of the brain becomes sluggish, leaving the more primitive, reactive parts of the brain, like the amygdala, in charge.
The result: you might be more likely to snap at your friend, yell at your steering wheel, or take something personally that might not have bothered you after a snack.
Evolutionary Roots of Hanger
From an evolutionary perspective, hanger makes sense. Early humans needed motivation to seek food and defend resources. Irritability and aggression could serve adaptive purposes when food was scarce – emotions evolved as action signals to ensure survival (Tooby & Cosmides, 2008). The surge in adrenaline and cortisol would help a hungry individual hunt, compete, or protect what little food they had.
In today’s world, however, that same biological system activates not in the wilderness but in a traffic jam or during a long meeting. The physiological drive remains, but the appropriate behavioral outlet – finding food – is delayed. This mismatch between our evolutionary wiring and our modern routines explains why so many people experience hanger in everyday life.
Hanger also illustrates how emotion depends on context. The same physiological state, low blood sugar, can lead to different outcomes depending on the situation and interpretation. If you are at home preparing dinner, hunger might feel like simple anticipation.
But if you’re in a tense conversation, your brain might interpret those same bodily sensations as anger or frustration. Emotions are essential, they can lead us in the right direction, but they are often blunt instruments – at some point, our more nuanced cognitive abilities need to tag in.
Emotional granularity, or the ability to precisely identify and label emotional states, can help mitigate hanger’s effects (Kashdan et al., 2015). When you can recognize, “I’m not mad, I’m frustrated and hungry,” you give yourself a chance to regulate more effectively. This cognitive reframing recruits the prefrontal cortex, reestablishing control and allowing for more constructive behavior. Maybe eat an apple, rather than pick a fight.
Hanger as a Reminder
Ultimately, hanger is not a personal flaw – it’s a physiological reminder of our mind-body unity. Our emotions are not detached from our biology; they are constructed through it. As Barrett (2017) notes, the brain’s primary job is not to think, but to regulate the body. Emotions like hanger are signals, not defects. They tell us something about what our body needs.
In a world that often prizes productivity over self-care, listening to these signals is a simple act of intelligence. A snack, a pause, or a good meal can restore not only your blood sugar but supports your empathy, patience, and sense of calm.
So the next time you feel that rising tide of irritability before dinner, don’t suppress it – work to understand it. Feed your body, and your brain will follow.
References
Barrett, L. F. (2017). How emotions are made: The secret life of the brain. Houghton Mifflin Harcourt.
Benton, D. (2002). Carbohydrate ingestion, blood glucose, and mood. Neuroscience & Biobehavioral Reviews, 26(3), 293–308. https://doi.org/10.1016/S0149-7634(02)00004-0
Benton, D., & Parker, P. Y. (1998). Breakfast, blood glucose, and cognition. American Journal of Clinical Nutrition, 67(4), 772S–778S. https://doi.org/10.1093/ajcn/67.4.772S
Crum, A. J., Salovey, P., & Achor, S. (2013). Rethinking stress: The role of mindsets in determining the stress response. Journal of Personality and Social Psychology, 104(4), 716–733. https://doi.org/10.1037/a0031201
Gailliot, M. T., Baumeister, R. F., DeWall, C. N., Maner, J. K., Plant, E. A., Tice, D. M., ... & Schmeichel, B. J. (2007). Self-control relies on glucose as a limited energy source: Willpower is more than a metaphor. Journal of Personality and Social Psychology, 92(2), 325–336. https://doi.org/10.1037/0022-3514.92.2.325
Kashdan, T. B., Barrett, L. F., & McKnight, P. E. (2015). Unpacking emotion differentiation: Transforming unpleasant experience by perceiving distinctions in negativity. Current Directions in Psychological Science, 24(1), 10–16. https://doi.org/10.1177/0963721414550708
MacCormack, J. K., & Lindquist, K. A. (2018). Feeling hangry? When hunger is conceptualized as emotion. Emotion, 18(2), 301–319. https://doi.org/10.1037/emo0000328
Müller, T. D., Nogueiras, R., Andermann, M. L., Andrews, Z. B., Anker, S. D., Argente, J., ... & Tschöp, M. H. (2015). Ghrelin. Molecular Metabolism, 4(6), 437–460. https://doi.org/10.1016/j.molmet.2015.03.005
Tooby, J., & Cosmides, L. (2008). The evolutionary psychology of the emotions and their relationship to internal regulatory variables. In M. Lewis, J. M. Haviland-Jones, & L. F. Barrett (Eds.), Handbook of emotions (3rd ed., pp. 114–137). Guilford Press.