This research explores reasons for the attitude-behavior gap of consumers involved with sustainable food choice. For this purpose, the Food Choice Process Model by was applied. The study follows a qualitative approach. Data were collected through ethnographical fieldwork. Over the course of nine months, researchers repeatedly accompanied six families. Each visit lasted several hours and included multiple in-depth discussions, food shopping observations and participation in everyday food behavior. Findings show that beliefs, positive attitudes, and behavioral intentions do play an important role for sustainable choice. Rooted in one’s personal life course experiences and the socio-cultural conditions one grew up in, however, their determinacy is heavily impaired by household realities and by various personal and situational factors. Sustainability attributes, even if dominant on an abstract level, tend to be inferior for actual choice, especially when competing with the taste, price, and preferences of other household members. Product evaluation and food choice are seldomly a result of comprehensive information processing, but rather based on simplifications and strategies. Conflicts are aggravated by competing sustainability values and attributes. Confronted with diverse product-related, personal, external, and situational influences, sustainable choices come with conflicts, tensions, and ambivalences forcing participants to make compromises and remain flexible in their decisions. However, participants were aware of their inadequacies and accept personal inconsistencies, without showing much dissonance. This research extends current knowledge about the impact and the origin of attitudes towards and barriers for sustainable food choice behavior that help to understand the complexity of the phenomena in its natural setting. It points out practical implications for practitioners, updates the theoretical framework, and can widen researchers’ perspective on sustainable food choice behavior.