Eating late at night is generally regarded as an unhealthy habit, with experts arguing that it messes with our body clock, which in turn increases our chances of things such as anxiety and depression. A new study from North Carolina State University suggests that it might also have a negative impact on our performance at work too.

The study suggests that adopting unhealthy eating behaviors during the night runs the risk of making us more withdrawn and generally less helpful the following day at work.

“For the first time, we have shown that healthy eating immediately affects our workplace behaviors and performance,” the researchers explain.  “It is relatively well established that other health-related behaviors, such as sleep and exercise, affect our work. But nobody had looked at the short-term effects of unhealthy eating.”

Unhealthy habits

The researchers recruited a number of full-time employees from the United States and quizzed them three times a day for two working weeks. Before work each day, the volunteers were asked about their general physical and emotional wellbeing. This was followed by a second questionnaire at the end of the workday, in which they were asked about their activities during the day. Finally, a third questionnaire was administered before bed, where the volunteers explained their eating and drinking behaviors that evening.

The researchers defined unhealthy eating in a number of ways, including the consumption of junk food, excessive consumption of food and/or drink, or partaking in late-night snacking.

The results revealed that when we engage in various unhealthy eating behaviors, we're far more likely to report suffering from various physical problems the following morning. These problems range from headaches and stomach aches to diarrhea.

Emotional strain

What's more, people were also far more likely to report various emotional strains the morning after a night of unhealthy eating. These unsurprisingly include feelings of guilt or shame about their eating habits.

Perhaps unsurprisingly, this emotional strain then had a knock-on effect on the way people performed at work that day. The biggest consequence was in our ability and willingness to help others. Previous work has shown that our ability to engage in prosocial behavior diminishes as our mental reserves fall, and this is something found in this latest study too. 

Those who reported unhealthy eating behaviors would also report physical and emotional strain, which resulted in a reduction in their prosocial activities at work the following day. Prosocial activities include going the extra mile or volunteering to help a colleague, even if you don't have to.

A slippery slope

This matters, as research from Yale a few years ago, found that helping others is one of the more effective ways of battling the kind of stresses caused by unhealthy eating habits.

“Our research shows that when we help others we can also help ourselves,” the authors say. “Stressful days usually lead us to have a worse mood and poorer mental health, but our findings suggest that if we do small things for others, such as holding a door open for someone, we won’t feel as poorly on stressful days.”

By contrast, when people ate poorly, they were more inclined to exhibit withdrawal behavior, which generally results in us avoiding work-related situations and withdrawing within ourselves. It's a phenomenon commonly referred to as ghosting, as we're there but not there.

A mental buffer

It's perhaps notable that the study also found that people who were more emotionally stable and therefore better able to cope with stress and anxiety were also less likely to suffer adverse consequences from any unhealthy eating habits they indulge in.

The results show that such emotionally stable people were much less likely to suffer from physical or emotional strain, which in turn meant that their workplace behavior was less likely to suffer as a result.

“The big takeaway here is that we now know unhealthy eating can have almost immediate effects on workplace performance,” the researchers say. 

“Companies can help to address healthy eating by paying more attention to the dietary needs and preferences of their employees and helping to address those needs, such as through on-site dining options. This can affect both the physical and mental health of their employees—and, by extension, their on-the-job performance.”