Feeling irritable when hungry may not just be about low blood sugar alone. A new Lancet study reveals that when an individual consciously recognises hunger, it triggers mood swings.
It often begins with
a missed meal, a delayed snack, or the body running slightly low on fuel. Almost without warning, irritation starts setting in, minor frustrations feel amplified, and emotions become harder to blend in with everyday situations. Today’s culture has given this experience the name “hangry.”
While the feeling is universally familiar, science has now explained why hunger can so suddenly alter mood. The new study published in The Lancet in December 2025 suggests that hunger alone may not be responsible for those sudden mood swings. Instead, the emotional fallout may depend on something far more subtle, whether a person consciously realises that they are hungry.
What The Study Says
The study titled “Glucose levels are associated with mood, but the association is mediated by ratings of metabolic state,” followed 90 healthy adults over four weeks.
Participants wore continuous glucose monitoring (CGM) devices that recorded their glucose levels every few minutes. At the same time, they completed ecological momentary assessments (EMA) on their smartphones up to twice daily, rating both their mood and how hungry or satiated they felt on a scale from 0 to 100.
Hunger Alone Did Not Predict Mood, Awareness Did
The findings overturned a long-held belief. While lower glucose levels were associated with hunger, they did not automatically lead to a worse mood. Participants only reported feeling more irritable or low when they consciously acknowledged that they were hungry.
“Although glucose levels were associated with mood, the metabolic state ratings mediated this association,” the researchers wrote. In simpler terms, people felt worse not when their blood sugar dropped, but when they realised they were hungry.
This also suggests that hunger-related mood changes are not purely subconscious biochemical reactions. Instead, they involve a psychological step, the conscious sensing and interpretation of bodily signals.
Interoception: The Link Between Hunger And Emotion
Scientists call this internal sensing process interoception, the brain’s ability to detect and interpret signals from within the body, such as thirst, hunger, heart rate and fatigue.
The Lancet study found that individuals with higher interoceptive accuracy, meaning their hunger ratings closely matched their glucose levels, experienced significantly fewer mood fluctuations. “Notably, individuals with higher interoceptive accuracy had fewer fluctuations in mood ratings,” the researchers reported.
Importantly, these individuals still felt hungry. They were simply better at recognising and responding to that hunger before it destabilised their mood.
What Happens In The Brain When Hunger Strikes In
At the neurological level, hunger begins in the hypothalamus, a small but vital region responsible for maintaining the body’s internal balance. When energy levels drop for a prolonged period, specialised neurons detect this deficit and signal the need for food.
However, the conscious experience of hunger emerges elsewhere. That signal in the brain is processed by the insula. This deep-seated part of the cerebral cortex helps in translating these signals into feelings like discomfort, urgency and irritability.
The study also suggests that the mood changes occur when these hunger signals reach conscious awareness and are interpreted within a given context, such as stress, emotional load and distraction.
Why Some People Stay Calm While Others Snap
The key findings of the study also explain a question: why do some people remain calm when meals are delayed, while others become irritable quickly?
According to the study, it is not just the metabolic health, but the factors such as BMI (body mass index) and insulin resistance that did not significantly alter the relationship between hunger awareness, glucose and mood in healthy adults.
Instead, the key factor was how accurately individuals sensed their internal state. “We conclude that hunger-related mood shifts depend on conscious sensing of the body’s internal state instead of acting subconsciously,” the researchers wrote.
Why Children Are Prone To Hunger-Related Meltdowns
According to the research, young children are still developing interoceptive awareness. They are easily distracted by stimulation, routine changes, play and often fail to recognise hunger until it takes over the mood and brain.
When awareness finally takes the centre stage, the emotional regulation can collapse, resulting in anger, sudden tears or distress. Adults, too, are increasingly vulnerable. In a world of constant notifications, deadlines, and screen-based distractions, early hunger cues are often ignored. By the time hunger is acknowledged, mood has already shifted.
Mood, Behaviour And Everyday Consequences
Sudden mood swings have real-world consequences. Irritability can strain relationships with family, colleagues and friends. It can also affect decision-making and increase impulsivity, including a tendency to choose quick, high-energy foods that may undermine long-term health.
This study also highlights how closely mental and physical well-being are connected. “Deviating too much from the body’s ideal state can pose a long-term risk to our health, mental as well as physical,” the researchers noted.
Can Interoceptive Awareness Be Improved?
The findings suggest that mood stability may be improved not by eliminating hunger, but by responding to it earlier. Some simple strategies include reducing long gaps between eating, paying closer attention to bodily cues and maintaining regular mealtimes.
Physical activity has also been shown to sharpen hunger sensing and improve energy metabolism. By recognising hunger before it escalates, individuals may prevent emotional swings rather than react to them.
Rethinking What It Means To Be ‘Hangry’
The Lancet study explains the feeling of being ‘hangry’ and how hunger itself is not the villain. Instead, emotional instability emerges when hunger is noticed a bit late, interpreted as stress, or ignored until it overwhelms emotional regulation.
“Our findings demonstrate that hunger-related mood changes depend on consciously sensed metabolic states rather than subconscious signalling of glucose levels,” the researchers concluded.
A Shift With Big Impact
Traditionally, hunger has been thought to affect mood only modestly. The emotions are shaped by countless factors such as stress, sleep, relationships and environments. Yet hunger remains a uniquely powerful and easily overlooked trigger. Because sometimes, the difference between calm and conflict is not food itself, but the moment we realise we need it.
