Bonn, 9 December 2025 – When we are hungry, our mood often drops – a phenomenon colloquially known as “hangry.” A new study by the University Hospital Bonn (UKB), the University of Bonn, and the University Hospital Center Tübingen now shows that this connection is not caused by unconscious metabolic processes. Rather, the decisive factor is that the lack of energy is consciously perceived as hunger – it is this conscious feeling of hunger that leads to a worse mood. The results have now been published in the journal eBioMedicine.
In the study, the researchers examined how glucose levels, feelings of hunger, and mood influence each other in 90 healthy adults over a period of four weeks. The participants wore continuous glucose monitors (CGM), as used in diabetes care, and regularly answered questions about their current hunger, satiety, and mood (Ecological Momentary Assessment, EMA) via a smartphone app.
“When glucose levels drop, mood also deteriorates. But this effect only occurs because people then feel hungrier,” explains first author Dr. Kristin Kaduk, postdoctoral researcher at the University Hospital for Psychiatry and Psychotherapy in Tübingen. “In other words, it is not the glucose level itself that raises or lowers mood, but rather how strongly we consciously perceive this lack of energy.”
The study thus provides new evidence for the importance of interoception—the conscious perception of internal bodily states—in the regulation of emotions. People who were particularly sensitive to changes in their glucose levels also showed fewer mood swings.
“Our results suggest that consciously feeling your own body can act as a kind of buffer for your mood,” adds corresponding author Prof. Nils Kroemer, who works in Tübingen in the Department of Psychiatry and Psychotherapy at the University Hospital in the field of translational psychiatry and at the Clinic for Psychiatry and Psychotherapy at the UKB, and also conducts research as a professor of medical psychology at the University of Bonn. “A good sense of the body's own signals seems to help maintain emotional stability – even when energy levels fluctuate.”
The researchers also see this as an important basis for future studies in patients with metabolic or mental disorders.
“Many diseases such as depression or obesity are associated with altered metabolic processes,” says Prof. Kroemer. “A better understanding of how body perception and mood are related can help improve therapeutic approaches in the long term – for example, through targeted training of interoception or non-invasive stimulation of the vagus nerve, which connects the organs to the brain and influences interoception.”
The results underscore the close connection between metabolic and mental health—and show that conscious perception of one's own body is a central mechanism through which metabolic processes affect mood.
Participating institutions and funding:
In addition to the UKB, the University of Bonn, and the University Hospital of Tübingen, the German Center for Mental Health (DZPG) and the German Center for Diabetes Research (DZD) were also involved in the study. The study was funded by the German Research Foundation (DFG).
Publication: Kristin Kaduk, et al.; “Glucose levels are associated with mood, but the association is mediated by ratings of metabolic state”; eBioMedicine; DOI:
https://doi.org/10.1016/j.ebiom.2025.106035
Scientific contact:
Prof. Dr. Nils Kroemer
Department of Psychiatry and Psychotherapy
University Hospital Bonn (UKB)
Professor of Medical Psychology
University of Bonn
Phone: +49 228 287 11151
Email: Nils.Kroemer@ukbonn.de