Persistence: A key factor in understanding the circumstances under which dietary restraint predicts restriction of caloric intake.

Dietary restraint refers to the intention to restrict caloric intake, whereas dietary restriction refers to the actual intentional and sustained restriction of caloric intake for weight-control purposes. Findings regarding the relation between dietary restraint and restriction to date are inconsistent. Our study sought to clarify this complex relationship using a novel laboratory task. Participants (N = 103; 56.3% female) completed a Paced Visual Serial Addition Task (PVSAT). Participants were provided a choice between ending each of eight PVSAT rounds at any time and drinking a high-calorie Kool-Aid® mixture or correctly completing 10 consecutive computations to access to a zero-calorie mixture for each round. We measured participants' dietary restraint using the Three-Factor Eating Questionnaire - Restraint Subscale and measured persistence and dietary restriction using the PVSAT. Results indicated a positive association between persistence and restriction. Female participants demonstrated higher eating disorder psychopathology, dietary restraint, and dietary restriction compared to male participants. Restraint was positively associated with restriction the more individuals persisted, indicating that persistence is a potentially important modifier of the relation between dietary restraint and restriction. Our findings highlight the complexity of the relation between dietary restraint and restriction; that is, measures of dietary restraint alone may not reliably predict short-term dietary restriction during laboratory consumption tasks; however, other factors, such as persistence, may play critical roles.