Why You Shouldn't Make Decisions While You're Hungry

What do we, humans, have in common with other animals, including fruit flies? A lot more than we'd probably like to think, it turns out. Though the fruit fly's organism is tiny and far less complex than the human body, it possesses the ability to do some pretty advanced stuff, including detecting carbon dioxide levels.

The rotting produce fruit flies consume emits some carbon dioxide, but higher levels of carbon dioxide usually indicate that a breathing — and therefore potentially dangerous — life form is somewhere nearby. When well-fed, fruit flies steer well clear of environments with higher carbon dioxide levels.

It's a different story when they're hungry, though! A study discovered a specific neuron, something that biologically programs fruit flies to ignore carbon dioxide as danger sign when they're hungry. 

Though not through the same mechanism, that exact phenomenon can be observed pretty much throughout the animal world. Hungry predators are far more bold and dangerous than their well-fed counterparts, because they are more willing to take risks. Why? That's hardly a difficult question to answer — food is the stuff of life, and when its supply is in danger, it begins taking priority over all else, on a very primal, biological level. 

What does that mean for humans, though? Arranged in complex societies and possessing more advanced decision-making skills than any other animal, you'd think that we'd be slightly different to, say, fruit flies. To attain long-term survival and well-being, humans need so much more than food and water alone, after all! Hunger also comes in rather many different levels, ranging from famine-level starvation to the kind of stomach rumbling you may experience when you are on a calorie-restricted weight loss diet. Hunger can be chronic, or occasional. How does it affect our decision-making skills?

New Study Confirms: Hunger Leads To Poor Decisions

So, fruit flies have pinpointed neurons in their tiny bodies that biologically over-ride risk aversion when they are hungry. Just as avoiding high-carbon dioxide environments makes sense for fruit flies, delayed gratification is an essential quality in humans and some other animals. This ability means that we know that simply acting on impulse by doing what our brain tells us to do right now is a bad idea.

Some people, of course, are better at delaying gratification than others, and impulsivity is associated with a range of mental disorders, including ADHD, alcohol abuse disorder, and obsessive compulsive disorder. Where does food come into the picture? Since previous studies (more about that later) already suggested that there was a link between hunger and impulsivity, researchers from the Sahlgrenska Academy of the University of Gothenburg in Sweden wanted to find out more.

The catch is that their experiments involved rats rather than humans, but rats also have ghrelin. 

READ Breakfast Tricks That Help Kids Fight Hunger All Day

In the experiment, rats were first trained to get rewards for either pressing a lever or not doing so. The reward was food, of course. The rats would get more food if they waited a while than if they collected their reward right away. Researchers then injected ghrelin directly into the lab rats' brains to simulate the condition of being hungry.

Watch Out: Hunger Leads You To Take Irrational Risks!​

What About Humans, Then?

The hormone ghrelin, we now know, plays a key role in the underlying reason behind the fact that hunger can lead to poor decision making, or rather, perhaps, short-term decision making opposed to long-term planning. Unlike the very interesting rat study, however, humans have more decisions to make than whether we'd like one slice or pizza now, or several later. To what extent does rational risk assessment go out the window when humans are hungry, then? A 2010 study entitled Metabolic State Alters Economic Decision Making in Humans Under Risk sheds some light on that question. 

The study made the startling discovery that those study subjects who were purposely starved for the experiment — and thus under the influence of ghrelin — were far more willing to take financial risks in a gambling game than those who were well fed. The hungrier the subjects were, the more willing they became to take risks. 

What Does This Mean For You?

Research into how hunger influences human decision making and risk taking is still rather limited, however, and I'm sure we can expect lots of fascinating new findings over the coming years. How does nutritional quality impact how risk prone we are, for instance, as opposed to whether we are hungry or not? Do people with a history of hunger and malnutrition perhaps have the tendency to be more impulsive in the long-term, even during a time when they are no longer suffering from food shortages? Is there any way to counter the natural tendency towards impulsivity while hungry? One day, we'll hopefully have answers to all these fascinating questions. 

Meanwhile, though, the studies that currently do exist show us that hunger, too, has a place in the risk perception gap — the thing that explains why most people are more frightened of terrorist attacks than dying of smoking, for instance, or why a product they'd never usually buy suddenly becomes appealing when it's on special offer. 

READ Healthy Eating Starts At Home

The discovery that hunger leads to increased impulsivity and risk taking by essentially taking over our whole being on a subconscious level has far-reaching implications all in itself. It shows us that making financial and other important decisions while hungry is bad for us, and even has us questioning whether our political leaders or employers are taking appropriate care of their nutritional needs. Should we be worried if they are on a diet, perhaps? Finally, it tells us that, despite the scientific advances humans have made, we're really not all that different to any other animal.