Dieting and the self-control of eating in everyday environments: an experience sampling study

The literature on dieting has sparked several debates over how restrained eaters differ from unrestrained eaters in their self-regulation of healthy and unhealthy food desires and what distinguishes successful from unsuccessful dieters. We addressed these debates using a four-component model of self-control that was tested using ecological momentary assessment, long-term weight change, and a laboratory measure of inhibitory control.

A large sample of adults varying in dietary restraint and inhibitory control (as measured by a Stroop task) were equipped with smartphones for a week. They were beeped on random occasions and provided information on their experience and control of healthy and unhealthy food desires in everyday environments.

The main outcome measures were desire strength, experienced conflict, resistance, enactment of desire, and weight change after a 4-month follow-up.

Dietary restraint was unrelated to desire frequency and strength, but associated with higher conflict experiences and motivation to use self-control with regard to food desires. Most importantly, relationships between dietary restraint and resistance, enactment of desire, and long-term weight change were moderated by inhibitory control: Compared with dieters low in response inhibition, dieters high in response inhibition were more likely to attempt to resist food desires, not consume desired food (especially unhealthy food), and objectively lost more weight over the ensuing 4 months. These results highlight the combinatory effects of aspects of the self-control process in dieters and highlight the value in linking theoretical process frameworks, experience sampling, and laboratory-based assessment in health science.

What is already known on this subject? Dieting is a multifaceted process that can be viewed from the lens of self-control. Dietary restraint measures can be used to capture dieting status, but it is relatively unclear what differentiates successful from unsuccessful dieters (e.g., differences in desire frequency, desire strength, motivation, executive functions). What does this study add? A novel four-step conceptual model of self-control is applied to eating behaviour in everyday life. This model allows a fine-grained look at the self-control process in restrained eaters (dieters) as compared to non-dieters. Dieters and non-dieters do not differ in desire frequency and strength (they are not simply more tempted). Dieters high (as compared to low) in inhibitory control are more likely to engage in self-control. Dieters high (as compared to low) in inhibitory control are more likely to resist unhealthy food desires. Dieters high (as compared to low) in inhibitory control are more likely to loose weight over a 4-month period. Together, the study shows clear differences among successful and unsuccessful dieters that can be linked to differences in executive functioning (inhibitory control). The present article is one of the first studies combining a conceptual model with smartphone experience sampling to study weight control and thus paradigmatic from a methodological perspective.