The individual human behavior is seen as a significant contributor to the current socioenvironmental crisis. Among others, food consumption and the relating psychological factors play an important role in sustainable individual consumption behavior. One of these psychological factors is self-control. The main goal of the study was to investigate the effect of ego depletion, a state with no self-control resources available, on explicit and implicit attitudes and behavior towards sustainable food consumption within the framework of dual-process models describing sustainable behavior. A total of 171 participants completed an explicit rating task and an affective priming task before and after a six-minute transcription task intervention to induce ego depletion. Subsequently, participants conducted a decision-making task involving a choice between a sustainable and a less-sustainable chocolate bar to assess actual sustainable behavior during a state of ego depletion. The results showed that the explicit attitudes towards sustainable nutrition did not become more negative in the depletion group compared to the control group contrary to our initial expectation. However, unanticipated time-based changes in implicit attitudes towards sustainable nutrition were observed. Furthermore, the depletion group did not act dependent on their implicit attitudes towards the chocolate bars in the decision-making task. Although this study does not provide the expected effect of ego depletion on explicit and implicit attitudes to describe sustainable behavior, particularly vegetarian nutrition, it suggests, regarding dual-process models, that reflective type-2 processes are the predominant influence on explaining and describing sustainable behavior compared to affective type-1 processes.