Great Balls Against Food Waste—An Innovative Nudging Intervention Method

Food waste is one of the most pressing obstacles to sustainable development. Reducing food waste in schools and kindergartens constitutes an important component of sustainable waste management. To achieve this reduction, various interventions targeting food waste can deliver multiple benefits across environmental, social, and economic dimensions. Among these, behavioral “nudges” aim to steer consumer choices without restricting options. This study evaluated a novel nudging intervention in the canteens of two primary schools and one kindergarten, with the goal of reducing plate waste. The nudging intervention consisted of a simple, interactive installation designed to encourage children to reflect on their food consumption and portion choices. The installation was integrated into routine lunch service and it combined ball-based voting with visual prompts: the emptier the returned plate, the greater the voting weight for the pupil. Across all institutions the food waste level (soup and second dish combined) was significantly decreased during the nudging intervention: by 31% for primary school no. 84, 18% for school no. 1, and 33% for kindergarten no. 56, although part of this reduction was attributable to lower food production volumes. Plate waste for the second dish decreased in all the considered schools: by 10 g/meal (11%), 19 g/meal (22%), and 52 g/meal (51%), respectively. After the intervention a larger share of the second dish served was consumed than was left on the plates compared to the situation during the baseline monitoring. A shift from plate waste to unserved food, which was one of the goals of the study, could not be unambiguously confirmed. Overall, the new nudging installation appears effective. Substantial changes in food production complicate the possibility of determining the effects of the nudging intervention. Future research should maintain constant production levels across the baseline and intervention periods. In addition, pupils should be given maximum freedom to determine their portion sizes during the nudging intervention. The long-term effects of the nudging approach should also be evaluated.