Cognitive Training Therapy Improves the Effect of Hypocaloric Treatment on Subjects with Overweight/Obesity: A Randomised Clinical Trial

Abstract

Obesity has been associated with impaired cognitive performance. This study aimed to determine whether improvements in cognitive function may contribute to higher weight loss in patients with obesity. In this randomised, 12-week trial, participants with overweight/obesity were randomised into a cognitive training intervention (Cognitive) group or a cognitive-behavioural (Control) group. In addition, both groups followed a hypocaloric dietary treatment. Cognitive functioning measurements and anthropometrical parameters were evaluated. All cognitive measures improved in the intervention group (p < 0.005 in all contrasts). In controls, significant improvements in attention, flexibility and task planning were also observed. Regarding anthropometrical parameters, the effect of the intervention in the cognitive group was higher for the total percentage of weight loss, body mass index (BMI), body fat and waist circumference. Biochemical parameters improved in both groups. Attending to our data, cognitive training was more effective that the hypocaloric intervention alone, partly related to an improvement in the working memory. Despite the shortage of training interventions for executive functions in the context of weight control, this type of combined intervention could establish the first steps towards a more appropriate intervention for patients with obesity.

Executive Functions in Predicting Weight Loss and Obesity Indicators: A Meta-Analysis

“…The participants' characteristics are summarized in Table 2 . Eight studies (Verbeken et al, 2013 ; Allom and Mullan, 2015 ; Stice et al, 2015 , 2017 ; Houben et al, 2016 ; Dassen et al, 2018b ; Raman et al, 2018 ; Galindo Muñoz et al, 2019 ) with 716 participants were found, and one study (Allom and Mullan, 2015 ) included two independent substudies, for a total of 9 RCTs. Seven RCTs solely focused on one specific EF, and in particular, 4 of them focused on inhibition, 2 of them focused on working memory, and 1 focused on cognitive flexibility.…”

“…Seven RCTs solely focused on one specific EF, and in particular, 4 of them focused on inhibition, 2 of them focused on working memory, and 1 focused on cognitive flexibility. Four RCTs (Verbeken et al, 2013 ; Dassen et al, 2018b ; Raman et al, 2018 ; Galindo Muñoz et al, 2019 ) employed other weight loss interventions addition to the EF intervention. Regarding quality, 5 RCTs scored 3 points, 2 RCTs scored 2 points, and only 1 RCT scored 1 point.…”

“…For longitudinal studies, the standardized regression coefficient β was used as the effect size (Kim, 2011 ; Bowman, 2012 ). One RCT study (Galindo Muñoz et al, 2019 ) did not provide the posttest BMI standard deviation (SD), and we used baseline SD to estimate it (Higgins and Green, 2011 ). The standard error of β was calculated by β/t or SE × S X /S Y , where t is the result of the significance test, SE is the standard error of the unstandardized regression coefficient, S X is the variance in the independent variable, and S Y is the variance in the dependent variable.…”

“…However, randomized controlled trials (RCTs) investigating the effect of EF interventions have shown inconsistent results. While some studies claimed that weight loss intervention through improving EFs significantly reduced participants' BMI (Allom and Mullan, 2015 ; Raman et al, 2018 ; Galindo Muñoz et al, 2019 ), other studies did not find such a pattern (Houben et al, 2016 ; Dassen et al, 2018b ). A meta-analysis using RCTs that may reveal a causal inference is needed to assess these inconsistencies.…”

“…There are important clinical implications of determining whether EF can treat obesity. However, as discussed above, RCTs investigating the effect of EF interventions have shown inconsistent results (Verbeken et al, 2013 ; Allom and Mullan, 2015 ; Houben et al, 2016 ; Galindo Muñoz et al, 2019 ). A meta-analysis using RCTs that may reveal a causal inference is needed to assess these inconsistencies.…”