Background: Cognitive dysfunction is associated with obesity in mid-life it has been suggested that weight loss may be able to reverse these effects.
Aim: This study aims to systematically review the literature to identify what effect weight loss (via energy restriction) has on cognitive function in obese individuals.
Method: This review followed the PRISMA protocol for systematic literature reviews. The following databases were searched for terms synonymous with weight loss, energy restriction and cognitive function were paired with obesity; PsycInfo, Web of Science, EMBASE, CINAHL, Medline and Cochrane library. From a total of 4096 articles included in the search, 15 studies met inclusion criteria and were analysed in this review.
Results: Results were mixed. Findings suggest that energy restriction (and associated weight loss) may lead to some improvement in memory, divided attention, speed of processing and executive function. However, these improvements were not consistent across the literature and different modes of energy restriction (diet versus surgical intervention) led to different improvements across cognitive domains. Additionally, some studies reported sub tests within cognitive domains while others reported global or composite scores making comparisons difficult
Conclusion: Overall, weight loss did not have a consistent effect on cognitive function. Conclusions were limited by disparity in the literature with respect to the neurocognitive tests used and the reporting of results. There is a need for more highly controlled research using standardised testing and reporting protocols to facilitate meaningful comparisons within the literature. This may in turn enhance design of interventions to improve health in the obese population.