Many studies have explored the antecedents of food waste in the framework of the theory of planned behavior (TPB). Scholars have also made efforts to add explaining variables to the original TPB, with mixed results; they often fail to demonstrate the incremental validity of the extended models. In the current study, we sought to assess whether an extended TPB model including social emotions and Good Provider norms could predict intention to reduce food waste. We also measured two behaviors which may be predicted by intentions to reduce food waste: (1) reducing servings and (2) using leftovers. The results show that social emotions help explain leftovers utilization, whereas the Good Provider norms are inversely correlated to the reduction of servings. Compared to the traditional TPB model, the extended version has more predictive power, especially as regards reducing servings.