Hunger has a way of bleeding into our moods. When energy runs low, patience thins, irritation rises, and everyday frustrations can feel sharper — a familiar experience often summed up with the word “hangry.”
It’s easy to assume hunger affects mood in a straightforward biological way — energy drops, blood sugar shifts, and irritation follows. But new research suggests the connection is more psychological than previously thought.
In a study published in eBioMedicine, researchers found that changes in glucose levels only affected mood when people consciously experienced those changes as hunger. In other words, low energy alone wasn’t enough to sour someone’s mood — feeling hungry was the key factor.
“When glucose levels drop, mood also deteriorates. But this effect only occurs because people then feel hungrier,” said first author, Dr. Kristin Kaduk, in a press release. “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.”
Why Hunger Has Long Been Linked to Bad Moods
Scientists have long known that hunger and mood are linked, but the mechanism behind that connection has remained unclear. Glucose — the body’s primary energy source — has often been assumed to play a direct role, with drops in blood sugar thought to trigger irritability and low mood automatically. Yet studies that manipulate glucose levels have produced mixed results, sometimes finding mood effects and sometimes none at all.
One challenge has been separating unconscious metabolic signals from conscious bodily sensations. In everyday life, changes in energy are often experienced as hunger or satiety — subjective states that may shape mood more strongly than glucose levels alone.
Read More: What Causes Hunger, and Can Your Stomach Actually Shrink?
Tracking Hunger, Glucose, and Mood in Daily Life
To untangle how glucose, hunger, and mood interact outside the lab, the researchers followed 90 healthy adults over four weeks as they went about their daily routines. Participants wore continuous glucose monitors and completed brief phone-based check-ins up to twice a day, rating their hunger, satiety, and mood in the moment.
At first glance, glucose levels seemed tied to mood: higher readings lined up with a better overall mood state, and glucose tracked with how hungry or full participants felt. But the pattern shifted once the researchers accounted for subjective metabolic state (hunger minus satiety). The glucose–mood link largely faded, suggesting mood changes were driven less by glucose itself and more by whether people felt hungry.
“Our results suggest that consciously feeling your own body can act as a kind of buffer for your mood,” said corresponding author Nils Kroemer, in the press release. “A good sense of the body's own signals seems to help maintain emotional stability – even when energy levels fluctuate.”
The researchers also found that people whose hunger ratings more closely matched their glucose changes — a measure known as interoceptive accuracy — experienced fewer mood swings overall. Measures of metabolic health, including body mass index and insulin resistance, did not significantly alter the core findings in this healthy group.
Where Research on Hunger and Mood Goes Next
The findings highlight how closely metabolism and mental health are linked — and suggest that mood shifts may hinge on how clearly the body’s internal signals are consciously felt. The researchers say the work also lays groundwork for future studies in people with metabolic or mental health conditions.
“Many diseases such as depression or obesity are associated with altered metabolic processes,” said 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.”
Read More: The Science Behind Why We Get Hangry
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
- This article references information from the recent study published in eBioMedicine: Glucose levels are associated with mood, but the association is mediated by ratings of metabolic state
