Better sorry than safe: Making a Plan B reduces effectiveness of implementation intentions in healthy eating goals

Objective: Implementation intentions (if–then plans) are helpful to health behaviour change. As these plans specify only one goal-directed behaviour for one specific situation, however, their effectiveness may be limited when a planned behaviour is impossible to execute in situ. The present research examines whether and how planning more than one goal-directed response for the same situation (‘making a Plan B’) affects successful self-regulation of eating behaviour.

Design and main outcome measures: In Study 1, participants formulated either one or two plans, after which a lexical decision task was administered to assess association strength between the if-part and the then-part(s). In Study 2, the effect of making one, two or no plan(s) was assessed on actual eating behaviour, after which a Stroop task measured cognitive load as an additional explanatory mechanism.

Results: Study 1 revealed that making a Plan B disrupts the creation of strong if–then associations during plan formation. Study 2 showed that making a Plan B yields increased unhealthy food intake compared to making one or no plan, and induces greater cognitive load during plan enactment.

Conclusion: Making a Plan B interferes with essential cognitive processes during different stages of planning, leading to an increased likelihood of self-regulatory failure.