Can a short message change how we think about expired food?

When people learn that “best-before” doesn’t mean “unsafe,” their fear of expired food fades, and they’re suddenly more open to eating and sharing what they’d once have thrown away.

Study: Simple and smart—promoting consumers’ willingness to consume and offer expired but still edible food through an informational intervention. Image credit: Towfiqu ahamed barbhuiya/Shutterstock.com

In a recent study published in Frontiers in Psychology, researchers investigated whether a simple informational intervention could increase consumers’ willingness to eat and offer expired (but still perfectly physiologically safe) food. The study used a cohort of 558 Germans, comparing their willingness to consume or share expired food following exposure to information on the environmental and financial benefits of not discarding food nearing or slightly beyond its “best before” label date.

Study findings revealed that cases (participants who received the intervention) reported a slightly stronger personal norm to avoid waste and perceived modestly lower health risks from expired food. These findings suggest that simple informational interventions were found to influence consumers’ personal norms and risk perceptions.

Background

Modern food production systems have resulted in a staggering amount of surplus food, the vast majority of which, despite being edible and physiologically nutritious, is discarded.

A large portion of this wastage is now attributed to confusion about expiration dates; consumers mistakenly believe that a “best-before” date is a safety deadline, like a “use-by” date, leading them to discard food that is still perfectly safe to eat. In Germany alone, an average of 79 kilograms of food is wasted per person annually at the household level.

The psychology underpinning excessive food wastage presents a unique challenge, attributed to the substantial complexity of its decision-making process. Eating an expired item involves environmental concerns, perceived health risks, personal habits, and social norms. An effective intervention must address these psychological barriers directly, but environmental psychologists remain unaware of the types of interventions that may elicit desired outcomes.

About the study

The present study partially addresses this knowledge gap by investigating whether “simple and smart” informational interventions (education about the pros and cons of food wastage and how to identify food that is safe to consume despite a labelled “expiry date”) are sufficient to change personal norms and risk perceptions, thereby contributing to reduced food wastage.

The study was conducted online and comprised a cohort of 558 German adults who were randomly assigned to one of two groups: 1. The experimental group (EG) received a brief informational intervention that provided both “problem knowledge” (explaining the environmental impact of food waste) and “action knowledge” (giving specific tips, such as the fact that unopened yogurt is often edible for a week or more past its best-before date), and 2. The control group (CG) received a placebo intervention (general healthy-eating tips, but no specific knowledge of expired food products).

Following the intervention, participants were required to complete a hypothetical food-choice experiment comprising pairs of dairy products (yogurt and cheese) with different expiration dates: not yet expired, expired one day ago, or expired one week ago. Participants were asked to choose which they would consume themselves and which they would be willing to share (“offer”) with friends or family members.

All models were adjusted for participants’ sex, age, and other confounding sociodemographic factors. Self-consumption and sharing were modelled separately to elucidate their differences before and following experimental interventions.

Study findings

The present study revealed that consumers are generally more likely to consume expired (suboptimal) food themselves than to offer it to close friends or family (p < 0.001), thereby highlighting a key social barrier to reducing waste. However, study findings suggest that simple and smart informational interventions may be sufficient to improve the outcomes of this psychological barrier.

Specifically, compared to the control group, participants who received the informational intervention reported a significantly stronger (though small-effect) personal moral norm to consume expired food (p < 0.05) and perceived significantly lower but modest health risks associated with it (p < 0.05).

Comparative models found that, while participants demonstrated little or no change in their willingness to consume expired foods, the intervention group was significantly more willing to offer expired but still edible food to others (p < 0.05). A mediation analysis confirmed that this effect was driven by the changes in personal norms and perceived health risks, wherein scientifically provided information from trusted sources potentially empowered participants to feel it was morally right and safe to share the food rather than waste it.

Conclusions

The present study provides valuable insights into the psychology of food waste and demonstrates that simple, targeted information can be an effective tool for change. While study findings suggest that “simple and smart” interventions have the potential to influence rather than completely alter consumers’ personal food choices, they may also make people more comfortable sharing food that might otherwise have been thrown away.

However, the author cautions that the findings are based on self-reported, hypothetical decisions from a non-representative sample of German adults, meaning results should be interpreted carefully and confirmed in real-world settings.

Future public health campaigns should investigate and address the social dynamics of eating, empowering people not only to trust their own senses with expired food but to feel confident in sharing it with others.

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