The roles of autonomous motivation and self-control lapses in concurrent adherence to a gluten-free diet and a self-chosen weight loss plan in adults with coeliac disease.

Objective: Examine the correspondence between autonomous motivation, self-control lapses, and adherence, to a gluten-free diet (GFD) and weight loss plan in adults with coeliac disease; and assess the impact of the interaction of motivation style and self-control lapses on adherence to both diets. Design: Cross-sectional survey in 519 adults with coeliac disease, 238 of whom were also attempting weight loss. Main outcome measures: Adherence, motivation style, frequency of temptation and self-control lapses (e.g. when tired, stressed, happy) for GFD and weight loss plan. Results: Autonomous motivation was higher, and amotivation lower, for the GFD than weight loss; adherence to the two diets was unrelated. Similar circumstances led to temptation and self-control lapses across diets; both were less frequent for the GFD than weight loss. Motivation and self-control lapses explained 21% and 35% of the variance in adherence, respectively; the interaction between motivation and lapse frequency did not explain additional variance for either diet. Conclusions: There are clear benefits to developing autonomous motivations and strategies to resist temptation for both the GFD and weight loss. Understanding how these processes differ and interact across diets may lead to the design of interventions to improve adherence and weight outcomes in coeliac disease.