Research paper
Adriaanse MA, van Oosten JMF, de Ridder DTD, de Wit JBF, Evers C. Planning what not to eat: ironic effects of implementation intentions negating unhealthy habits. Personality and Social Psychology Bulletin. 2011 Jan;37(1):69-81. doi:10.1177/0146167210390523
Why we cite it
Demonstrates that the structure of an implementation intention critically determines its effectiveness. While replacement-focused if-then plans work well for breaking eating habits, negation-focused plans ("I will NOT eat X") actually backfire through ironic rebound effects — keeping the unwanted behavior mentally accessible and potentially strengthening it. Based on ironic process theory (Wegner 1994), this provides a practical guideline: always frame dietary if-then plans as approach goals (what to do instead) rather than avoidance goals (what not to do).