Why We Feel 'Hangry' Explained By Science Linking Our Bellies to Behavior

Hunger can affect emotions and decisions, according to new research that shouldn't surprise anyone who has ever been "hangry."

Researchers at the University of Exeter created mathematical models to determine how effective it is to "listen to your gut." They found that animal models that use a lot of brain power to tell them how to act are just as successful as animal models that get cues from their stomachs on how to act.

By considering your energy reserves, or the food in your stomach, your body understands how successful it has been at finding food in the past. In turn, it signals to the brain how to act (i.e. "Feed me now!"), without the brain having to process a lot of complex information.

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"Our model explains why there is link between our gut and our decisions," Andrew Higginson, a behavioral scientist at the University of Exeter said in a press release. "Hunger can act as a memory telling us there's not been much food around...The usefulness of such memory means that animals, including humans, may appear to be processing a great deal of information in the brain when in fact they are just following their gut."

Higginson and other researchers created a mathematical model with hypothetical sample animals, some of which used both their brains and their gut instincts to survive. Other model animals used no gut instinct, but higher brain power. The researchers found that both sets of animal models "lived" similar amounts of time. The study was published in the journal Proceedings of the Royal Society B.

Having a big brain to analyze complex situations has its benefits, but it has its drawbacks, too. Brains aren't the most efficient organs, and it takes a lot of calories to keep big ones running. In humans, for example, the brain takes up only 2 percent of the body mass, but consumes about 20 percent of the body's oxygen, according to a 1981 study.

This study illuminates the connection between physiology, emotions and actions. As we know from biology class, emotions, such as fear, can trigger a physical response—the release of adrenaline—in the body. In turn, the body acts out a fight-or-flight response.

By listening to your body, people and animals can react more quickly to situations than if they spend a lot of time thinking about them, according to the researchers. In the press release, Higginson points out that, as climate change creates unpredictable changes in the environment, it's a good thing that animals can rely on their guts to survive.