Measuring food wasting behaviour at the consumer level is challenging. Most existing methods focus on food wasting at the household level, which in turn limits the possibility to study the situational and individual factors shaping food wasting behaviour in a single person. To fill this gap, we conducted a series of pre-registered studies in which we developed the Food Wasting Behaviours Questionnaire (FWBQ), an inexpensive method suitable for assessing and monitoring food wasting behaviour at the single-person level. We found that a wide range of behaviours associated with food wasting could be narrowed down to five distinctive basic categories: (1) discarding food because of its’ unpalatability; (2) preventing food waste through buying only the necessities; (3) preventing food waste through planning meals and groceries; (4) preventing food waste through sharing food with others; and (5) preventing food waste through feeding animals. The FWBQ allowed us to investigate the socio-economic factors that influence food wasting behaviour, such as food insecurity. Furthermore, because we started our research programme before the pandemic, we were able to conduct a natural experiment and observe that people changed their food wasting behaviour during the pandemic. Finally, we found that FWBQ allowed for predicting the amount of wasted meat, dairy and bakery products. In summary, we have demonstrated the potential utility of the FWBQ, an inexpensive and easy-to-use method for predicting the factors and antecedents of food wasting behaviour.