The role and trainability of executive function in the context of healthy eating

Abstract

Minimising intake of dietary fats and consuming appropriate amounts of fruit and vegetables reduce the risk of numerous negative health consequences. Self-regulation, and the processes underlying this capacity, namely executive functions, have been proposed to influence the adoption and maintenance of such healthy eating behaviours. In this thesis, a multi-method approach was taken to establish which facets of executive function were involved in healthy eating behaviour and whether these could be modified to improve eating behaviour. The results of a series of focus groups and a prospective study revealed that inhibitory control was specifically involved in fat intake, while updating ability was involved in fruit and vegetable consumption. A meta-analysis of current inhibitory control training studies revealed the need to assess change in eating behaviour using ecologically valid measures of eating behaviour, and to assess the mechanisms by which inhibitory control training influence eating behaviour. Results of an intervention based on these findings revealed that behaviour-specific stop-signal training led to a reduction in body mass index, which was mediated by changes in vulnerability to depletion. However, training did not result in a reduction in fat intake or an increase in inhibitory control capacity. The intervention was replicated to assess the reliability and longevity of the effects and to address methodological limitations. Results revealed that both behaviour-specific and general inhibitory control training improved inhibitory control capacity and decreased vulnerability to depletion; however, these improvements did not result in behaviour change, nor did they persist over time. While it appears that inhibitory control training alone may not be a suitable technique to change everyday eating behaviour, this technique may be efficacious for short-term improvement in self-regulatory outcomes, or when combined with other behaviour change techniques.