The purpose of the study reported in this paper was to examine the effects of reflective journals on students' learning, how they foster students' growth mindset, and the students' own perceptions of the journaling process. To this end, 15 students enrolled in an introduction to nutrition course participated in writing reflective journals about their eating habits with respect to the course content. This research used a qualitative instrumental case study design and the required data were collected from students' journals and focus group interviews. A content analysis approach was employed to examine the journals and this indicated that reflective writing improves learners' conceptual understanding of the course, promotes growth mindset, and helps shed light on the students' inner thoughts. The finding of this study revealed that reflective journal writing has a significant impact on EFL learners' understanding of concepts and on fostering growth mindset.