When hunger strikes and your patience thins, it is easy to blame blood sugar. A new study from researchers in Bonn and Tübingen suggests the story is more nuanced.
The team followed 90 adults for four weeks and found that dips in glucose were linked to worse mood only when people consciously felt hungry at the same time. In other words, it was the experience of hunger that explained why mood shifted.
Lead author Dr. Kristin Kaduk put it simply.
“When glucose levels drop, mood also deteriorates. But this effect only occurs because people then feel hungrier,” she said. She noted that the findings suggest “it is not the glucose level itself that raises or lowers mood, but rather how strongly we consciously perceive this lack of energy.”
Participants wore continuous glucose monitors while answering smartphone prompts throughout the day about hunger, satiety and mood. This moment-to-moment design allowed researchers to examine what tracked together in daily life. The team found that people with a stronger ability to sense changes in their own internal state tended to report fewer mood swings during periods of lower energy.
The work, published in eBioMedicine, adds to a growing body of research on interoception, the awareness of signals that come from inside the body. Corresponding author Prof. Nils Kroemer said the results suggest that tuning into those signals may support emotional stability.
“A good sense of the body's own signals seems to help maintain emotional stability even when energy levels fluctuate,” he said.
This line of research may be especially relevant for conditions where metabolic and emotional regulation intersect.
“Many diseases such as depression or obesity are associated with altered metabolic processes,” Kroemer said.
He added that understanding how people perceive those internal shifts may eventually help shape therapies that strengthen body awareness or use noninvasive stimulation of the vagus nerve, which plays a key role in how organs communicate with the brain.
For now, the study offers a grounded takeaway. Feeling “hangry” may be less about numbers on a glucose sensor and more about how clearly the body registers hunger as it happens.
The study was funded by the German Research Foundation. Additional support and participation came from the German Center for Mental Health and the German Center for Diabetes Research.