Your mother was right (as always)! Do not make decisions on an empty stomach. Mums have been dispensing this advice for generations, and now science backs them up.



A 2019 research by the University of Dundee found that making decisions while hungry is not a good idea. The study found that an empty stomach does not just lead to questionable grocery shopping; it fundamentally changes how you evaluate the situation. The findings are published in the journal
Psychonomic Bulletin & Review.








An empty stomach leads to questionable decisionsWe have all been there: heading to the grocery store on an empty stomach and coming back with everything but the staples originally planned. However, the impact goes beyond impulsive grocery purchases. The study warned against making any important decisions about the future on an empty stomach.



Led by Dr Benjamin Vincent from the university’s Psychology Department, this 2019 study found that , making them impatient and more likely to settle for a small reward that arrives sooner than a larger one promised at a later date.



The researchers conducted an experiment in which participants were asked questions relating to food, money, and other rewards when satiated and again when they had skipped a meal.



The findings were clear: the hungry participants were more likely to settle for smaller food incentives that arrived sooner. The researchers concluded that being hungry actually changes preferences for rewards entirely unrelated to food. The findings reveal that an inability to delay gratification could extend to other decisions, including financial and interpersonal ones.



Hunger affects preferences in ways you can’t predictDr Vincent noted that people must understand that hunger might affect their preferences in ways they do not necessarily predict. There is also a risk that individuals experiencing hunger due to poverty may make decisions that entrench their situation.



“We found there was a large effect: people’s preferences shifted dramatically from the long to the short term when hungry. This is an aspect of human behaviour which could potentially be exploited by marketers, so people need to know their preferences may change when hungry,” Dr Vincent said.



“People generally know that when they are hungry, they should not really go food shopping because they are more likely to make choices that are either unhealthy or indulgent. Our research suggests this could have an impact on other kinds of decisions as well. Say you were going to speak with a pension or mortgage adviser — doing so while hungry might make you care a bit more about immediate gratification at the expense of a potentially more rosy future. This work fits into a larger effort in psychology and behavioural economics to map the factors that influence our decision-making. This potentially empowers people, as they may foresee and mitigate the effects of hunger, for example, that might bias their decision-making away from their long-term goals,” he said.



How patience disappears







The researchers tested 50 participants twice: once when they had eaten normally and once when they had not eaten anything that day. People preferred smaller hypothetical rewards when hungry rather than larger ones that would arrive later. Well-fed individuals were typically willing to wait 35 days for the doubled reward; hungry participants would wait only three days.



“We wanted to know whether being in a state of hunger had a specific effect on how you make decisions only relating to food or if it had broader effects, and this research suggests decision-making becomes more present-focused when people are hungry. You would predict that hunger would impact people’s preferences relating to food, but it is not yet clear why people get more present-focused for completely unrelated rewards,” Dr Vincent said.



“We hear of children going to school without having had breakfast, many people are on calorie-restricted diets, and lots of people fast for religious reasons. Hunger is so common that it is important to understand the non-obvious ways in which our preferences and decisions may be affected by it,” he added.



A 2021 study published in the journal
Springer Nature Link also found that when people are hungry, their decision-making shifts towards more basic, , which relies on quick rewards rather than long-term planning.




Note: The information provided in this article is for educational purposes only and is not intended as medical advice. Always consult a qualified healthcare professional before starting any new medication or treatment, or before changing your diet or supplement regimen.