Objective: The study aimed to extend previous research into the impaired cognitive performance of spontaneous dieters by employing the Double Span Memory Task to investigate the relationship between weight-loss dieting and performance simultaneously on the three subsystems of working memory.
Method: A sample of 33 dieting and 33 non-dieting women were presented with increasingly longer sequences of common objects, displayed successively in different, randomly chosen locations of a 4 x 4 grid. Participants were then asked to name the objects (phonological loop), point to the locations (visuospatial sketch pad), or both (central executive). Participants also completed self-report measures of preoccupying cognitions, dietary restraint, depressed affect, and verbal intelligence.
Results: Current dieters performed more poorly than non-dieters on combined recall, but not on the single recall of objects or locations. They also scored more highly on self-rated preoccupying cognitions.
Conclusion: Dieting to lose weight selectively impairs central executive functioning, rather than the storage capacity of the two slave systems. This dieting-related central executive deficit is at best partly attributable to the preoccupying thoughts about food, weight, and body shape accompanying dieting.