Meal planning under uncertainty: How shopping frequency affects food waste

Food waste is the undesired result of multiple household food management routines. To reduce this food waste, interventions typically promote either food waste prevention or food waste recovery behaviours. These behaviours can be contradictory when it comes to shopping practices. Food waste prevention strategies suggest shopping for multiple days at once to benefit from planning and coordinate food packages with the needs of several days, whereas food waste recovery advocates for more frequent shopping trips to account for the unpredictability of everyday life. This study isolates the impact of shopping frequencies on food waste, assessing its effects across varying levels of uncertainties related to who will be present for dinner. A mathematical meal planning model is formulated to generate dinner meal plans and shopping lists by selecting combinations of recipes while considering nutritional adequacy and package sizes. The model uses a rolling horizon approach to simulate meal planning for household situations that are facing varying uncertainties in ingredient needs. As a base case, the model is run over a 21-day horizon for a household of four persons. The analysis reveals a trade-off between the flexibility of frequent shopping and the benefits of coordinating food purchases. Households with higher uncertainty in food requirements benefit from more frequent shopping compared to those with more stable needs, with total food waste across shopping frequencies ranging from 0–52 grams, 46–300 grams, and 50–900 grams per 21-day horizon for low-, medium-, and high-uncertainty household profiles, respectively. Moreover, the findings show that food waste can be minimized to 3 grams per day across all uncertainty levels by selecting recipes based on the food items already in stock at home. These insights suggest that tailored shopping and meal planning strategies based on household uncertainty levels can substantially reduce food waste and inform targeted interventions.