We assessed the motivations, commitment, and subjective well‐being (SWB) of 441 food bank volunteers, using motivation scales derived from self‐determination theory and functional motives theory. Replicating the findings of Sheldon, Wineland, Venhoeven, and Osin's (2016) study of environmental activists, all motivation scales could be located on the autonomous or controlled motivation factors specified by self‐determination theory (SDT). In addition, SDT's intrinsic motivation construct was the best predictor of volunteer commitment and SWB. As a novel angle, we compared food bank volunteerism to a second free time activity, that was focused on the self rather than helping others. Participants reported less self‐determined motivation and lower SWB in the food bank activity, suggesting that volunteerism may impose costs, compared to self‐focused activities. We interpret the latter results via the Eudaimonic Activity Model (Martela & Sheldon, 2019), concluding that activities that sound eudaimonic, based on their virtuous aims, are not necessarily so, based on their underlying motivations.