This study revealed that body dissatisfaction and body image inflexibility were mediators of the relationship between body mass index and dietary restraint in a large Chinese young adult sample. Our findings suggest that dietary restraint may be attenuated by addressing body dissatisfaction and body image inflexibility and future interventions target at reducing dietary restraint or other dietary restraint-related disordered eating behaviors may benefit by taking body dissatisfaction and body image inflexibility into consideration to have better intervention outcomes.