Neuropsychological assessment as a predictor of weight loss in obese adolescents

Current perspectives on brain circuits involved in food addiction-like behaviors

There is an emerging view that the increased availability of energy-dense foods in our society is contributing to excessive food consumption which could lead to food addiction-like behavior. Particularly, compulsive eating patterns are predominant in people suffering from eating disorders (binge-eating disorder, bulimia and anorexia nervosa) and obesity. Phenotypically, the behavioral pattern exhibits a close resemblance to individuals suffering from other forms of addiction (drug, sex, gambling). Growing body of evidence in neuroscience research is showing that excessive consumption of energy-dense foods alters the brain circuits implicated in reward, decision-making, control, habit formation, and emotions that are central to drug addiction. Here, we review the current understanding of the circuits of food addiction-like behaviors and highlight the future possibility of exploring those circuits to combat obesity and eating disorders.

The effect of continuous theta burst stimulation on antipsychotic-induced weight gain in first-episode drug-naive individuals with schizophrenia: a double-blind, randomized, sham-controlled feasibility trial

Antipsychotic intake may induce weight gain in drug-naive individuals with schizophrenia, leading to poor compliance in clinical management. However, there is still a lack of effective approaches to treat or prevent this side-effect. Therefore, we conducted this pilot study to investigate the effect of continuous theta burst stimulation (cTBS), a non-invasive magnetic stimulation technique, on preventing olanzapine-induced weight gain. Thirty-nine first-episode drug-naive individuals with schizophrenia were randomly assigned to receive either the active or sham cTBS intervention for 25 sessions (5 times per day for 5 consecutive days). The primary outcomes were changes in body weight and body mass index (BMI). Secondary outcomes included psychiatric symptoms, eating behavior scales, behavior tasks, and metabolic measures. For the result, the body weight and BMI increased significantly in the sham group but not in the active group, with a significant group effect. The active group exhibited a selective increase in the cognitive restraint domain in the Three-Factor Eating Questionnaire (TFEQ-CR) and a decrease in stop-signal reaction time compared to the sham group. The effect of cTBS on body weight was mediated by TFEQ-CR. Our findings demonstrated the feasibility that cTBS intervention could be a potential method for preventing olanzapine-induced weight gain in drug-naive first-episode schizophrenia patients through enhancing cognitive restraint to food. Trial registration: clinical trial registered with clinicaltrials.gov (NCT05086133).

Functional activity of the caudate mediates the relation between early childhood microstructural variations and elevated metabolic syndrome scores

BACKGROUND

Metabolic syndrome score in children assesses the risk of developing cardiovascular disease in future. We aim to probe the role of the caudate in relation to the metabolic syndrome score. Furthermore, using both functional and structural neuroimaging, we aim to examine the interplay between functional and structural measures.

METHODS

A longitudinal birth cohort study with functional and structural neuroimaging data obtained at 4.5, 6.0 and 7.5 years and metabolic syndrome scores at 8.0 years was used. Pearson correlation and linear regression was used to test for correlation fractional anisotropy (FA) and fractional amplitude of low frequency fluctuations (fALFF) of the caudate with metabolic syndrome scores. Mediation analysis was used to test if later brain measures mediated the relation between earlier brain measures and metabolic syndrome scores. Inhibitory control was also tested as a mediator of the relation between caudate brain measures and metabolic syndrome scores.

RESULTS

FA at 4.5 years and fALFF at 7.5 years of the left caudate was significantly correlated with metabolic syndrome scores. Post-hoc mediation analysis showed that fALFF at 7.5 years fully mediated the relation between FA at 4.5 years and metabolic syndrome scores. Inhibitory control was significantly correlated with fALFF at 7.5 years, but did not mediate the relation between fALFF at 7.5 years and metabolic syndrome scores.

CONCLUSIONS

We found that variations in caudate microstructure at 4.5 years predict later variation in functional activity at 7.5 years. This later variation in functional activity fully mediates the relation between microstructural changes in early childhood and metabolic syndrome scores at 8.0 years.

Current and future pharmacotherapies for obesity in children and adolescents

Obesity is a common chronic disease in children and adolescents and its prevalence is increasing worldwide. The causes are multifactorial but involve biological predisposition towards a specific body-weight set point and defended adipose tissue mass converging with an obesogenic environment. Comprehensive treatment of paediatric obesity includes lifestyle modification therapy, anti-obesity medications (AOMs) and/or metabolic surgery. Lifestyle modification therapy used alone produces fairly modest weight loss for most youth with obesity. The emergence of new AOMs has changed the landscape of paediatric weight management, improving the outlook for youth with obesity. This Review briefly highlights obesity development pathways in youth and the role that pharmacotherapy can play in counteracting these pathophysiological forces. Here, results from adolescent AOM clinical trials published since 2020 are reviewed, including the safety, efficacy and tolerability of the newest treatments (glucagon-like peptide 1 receptor agonists and phentermine-topiramate). The importance of a comprehensive and chronic care model, including both lifestyle modification and ongoing pharmacotherapy, will be discussed in the context of maximizing long-term health outcomes. Finally, insight will be provided into the emerging pipeline of AOMs (for example, incretin receptor co-agonists and tri-agonists) and how future therapies might fundamentally change the prognosis for youth with obesity.

Neural correlates of inhibitory control in severe class III compared with class I/II obesity using a sample of endometrial cancer survivors seeking weight loss

OBJECTIVE

No prior studies have evaluated inhibitory control in people with severe class III compared with class I/II obesity. Thus, the study aim was to evaluate inhibitory control and neural correlates of response inhibition by obesity class using a sample of endometrial cancer (EC) survivors with obesity, who have a higher risk of overall but not cancer-specific mortality.

METHODS

Forty-eight stage I EC survivors with obesity (class I/II: n = 21; class III: n = 27) seeking weight loss in a lifestyle intervention at baseline completed a stop signal task during functional magnetic resonance imaging.

RESULTS

It was found that participants with class III obesity had a longer stop signal reaction time (mean [SD], 278.8 [51.3] vs. 251.5 [34.0] milliseconds, p < 0.01) compared with those with class I/II obesity, indicating that patients with EC with severe obesity had greater impulsivity and poorer inhibitory control. Results also showed increased activation in the thalamus and superior frontal gyrus for the incorrect versus correct inhibition contrast in class III but not class I/II obesity (whole brain cluster corrected, p < 0.05).

CONCLUSIONS

These results provide novel insights into inhibitory control and corresponding neural correlates in severe versus less severe classes of obesity and highlight the importance of targeting inhibitory control processes in weight-loss interventions, particularly for people with severe obesity and greater impulsivity.

Inhibitory control as a potential treatment target for obesity

OBJECTIVES

Strong reward responsiveness to food and insufficient inhibitory control are thought to be implicated in the development and maintenance of obesity. This narrative review addresses the role of inhibitory control in obesity and weight loss, and in how far inhibitory control is a promising target for weight loss interventions.

METHODS

PubMed, Web of Science, and Google Scholar were searched for papers up to May 2021. 41 papers were included.

RESULTS

Individuals with obesity have poorer food-specific inhibitory control, particularly when hungry, and less concurrent activation of inhibitory brain areas. Moreover, this was strongly predictive of future weight gain. More activation of inhibitory brain areas, on the other hand, was predictive of weight loss: individuals with successful weight loss initially show inhibitory brain activity comparable to that of normal weight individuals. When successful weight maintenance is achieved for at least 1 year, this inhibitory activity is further increased. Interventions targeting inhibitory control in obese individuals have divergent effects. Firstly, food-specific inhibitory control training is particularly effective for people with low inhibitory control and high BMI. Secondly, neuromodulation paradigms are rather heterogeneous: although rTMS to the left dorsolateral prefrontal cortex induced some weight-loss, multiple sessions of tDCS reduced food consumption (desire) and induced weight loss in two thirds of the papers. Thirdly, neurofeedback results in successful upregulation of brain activity and connectivity, but occasionally leads to increased food intake. In conclusion, inhibitory control is implicated in obesity. It can be targeted to promote weight loss although major weight losses have not been achieved.

Relation of BOLD response to food-specific and generic motor response inhibition tasks to body fat gain in adults with overweight and obesity

BACKGROUND

Low inhibitory control has been theorized to contribute to the development and maintenance of obesity. Knowledge on the neurobiological indicators of inhibitory control deficits predicting future weight gain is limited. The current study examined if individual differences in blood-oxygenation-level-dependent (BOLD) activity associated with food-specific and general motor response inhibition predict future body fat change in adults with overweight or obesity.

METHODS

BOLD activity and behavioral responses of adults with overweight or obesity (N = 160) were recorded while performing a food-specific stop signal task (n = 92) or a generic stop signal task (n = 68). Percent body fat was measured at baseline, posttest, 3-month, and 6-month follow-up.

RESULTS

Elevated BOLD activity in somatosensory (postcentral gyrus), and attention (precuneus) regions during successful inhibition in the food-specific stop signal task and elevated BOLD activity in a motor region (anterior cerebellar lobe) in the generic stop signal task predicted greater body fat gain over 6-month follow-up. Elevated BOLD activity in inhibitory control regions (inferior-, middle-, superior frontal gyri) and error monitoring regions (anterior cingulate cortex, insula) during erroneous responses in the generic stop signal task predicted body fat loss.

CONCLUSIONS

Results suggest that improving motor response inhibition and error monitoring may facilitate weight loss in adults with overweight and obesity.

Potential contributors to variation in weight-loss response to liraglutide

Obesity treatment requires a chronic state of negative energy balance. Obesity medications can help with this, increasing long-term dietary compliance by promoting satiety or reducing hunger. However, efficacy and safety of obesity medications vary for individuals. Early identification of non-responders to obesity medications may limit drug exposure while optimizing benefits for responders. This review summarizes factors that impact weight-loss response to liraglutide. Factors linked to greater weight loss on liraglutide include being female, not having diabetes, having relatively high baseline weight, and losing at least 4% of initial weight after 16 weeks of treatment. Other covariates that may predict treatment response but require further confirmation include central effects, nausea, gastric emptying of solids, and genotype. Baseline body mass index, race, and age seem less relevant for predicting weight-loss response to liraglutide. Lesser known and harder-to-measure factors such as cerebral blood flow, food cue reactivity, gut hormone levels, and dietary adherence possibly impact variability of response to liraglutide. This information should assist healthcare providers with establishing realistic weight-loss probability for individual patients. Future research should improve the ability to identify responders to liraglutide. Importantly, this review may provide a framework to identify responders to other obesity medications.

Associations of Food Reinforcement and Food- Related Inhibitory Control with Adiposity and Weight Gain in Children and Adolescents

Some, but not all studies have reported that, among youth with disordered eating and high weight, the relative reinforcing value of food (RRV-F, i.e., how hard a person will work for a high-energy-dense food when another reward is available) is greater, and food-related inhibitory control (i.e., ability to withhold a response to food-related stimuli) is lower, compared to peers without disordered eating or overweight. In most studies, high RRV-F and low food-related inhibitory control have been studied separately, as independent factors, with each suggested to predict excess weight and adiposity (fat mass) gain. We hypothesized that the interaction of these factors would prospectively exacerbate risk for weight and adiposity (fat mass) gain three years later in a sample of healthy youth. At baseline, RRV-F was measured using a Behavior Choice Task with the rewards being standardized servings of chocolate candies, cheese crackers, or fruit snacks. Food-related inhibitory control was determined by performance in response to food and non-food stimuli during a Food Go/No-Go task. At baseline and 3-year visits, total body adiposity was measured by dual-energy X-ray absorptiometry (DXA) and body mass index (BMI) was obtained using measured weight and height. A linear regression was conducted with 3-year adiposity as the dependent variable. RRV-F, food-related inhibitory control, and the RRV-F x food-related inhibitory control interaction as independent variables. Baseline adiposity, age, height, sex, race/ethnicity, and days between visits were included as covariates for model predicting 3-year adiposity. Baseline BMI, age, sex, race/ethnicity, and days between visits were included as covariates for model predicting 3-year BMI. One-hundred and nine youth (mean 12.4±2.7y, mean 0.50±1.02 BMIz, 30.3% with overweight/obesity, 45.9% female, 51.4% non-Hispanic White), 8-17 years at baseline, were studied. Baseline food-related inhibitory control (β_{unstandardized} = .33, p = .037, 95% CI [.02, .64]), but not baseline RRV-F (β_{unstandardized} = -.003, p = .914), 95% CI [-.05, .05]) was significantly associated with 3-year adiposity such that those with the lowest food-related inhibitory control had the greatest adiposity gain. The interaction between RRV-F and food-related inhibitory control did not predict 3-year adiposity (β_{unstandardized} = -.07, p = .648, 95% CI [-.39, .25]). The pattern of findings was the same for models examining non-food related inhibitory control. Neither baseline food-related inhibitory control (β_{unstandardized} = 2.16, p = .256, 95% CI [-1.59, 5.92]), baseline RRV-F (β_{unstandardized} = .14, p = .660, 95% CI [-.48, .75]), nor their interaction (β_{unstandardized} = -1.18, p = .547, 95% CI [-5.04, 2.69]) were significantly associated with 3-year BMI. However, non-food related inhibitory control (β_{unstandardized} = .54, p = .038, 95% CI [.22, 7.15]) was significantly associated with 3-year BMI. In summary, food-related inhibitory control but not RRV-F, was associated with changes in adiposity in a sample of children and adolescents. Among generally healthy youth, food-related inhibitory control may be a more relevant risk factor than food reinforcement for adiposity gain. Additional data are needed to determine how impulsivity and reward systems, as well as other disinhibited eating behaviors/traits, may interact to promote excess weight gain over time in youth.

Opinions from the experts: Experiences of adolescents with severe obesity participating in meal replacement therapy

BACKGROUND

Meal replacement therapy (MRT) is a structured treatment that is effective for short-term weight reduction in adolescents with severe obesity. However, like other interventions, MRT response is variable.

OBJECTIVE

The goal of the current study was to characterize the experience of adolescents with severe obesity participating in MRT.

METHODS

Seventeen adolescents with severe obesity participated in semi-structured, individual interviews about their experience participating in MRT. The authors used a biopsychosocial model as the theoretical framework and data was analysed using Interpretive Phenomenological Analysis. A biopsychosocial model views an individual's health as a blend of biological characteristics, behavioural factors, and social conditions.

RESULTS

Results showed that adolescents with severe obesity described three biopsychosocial factors that were central to their experience with MRT: (1) scheduling and planning, (2) social support and pressure, and (3) intrapersonal factors. Specifically, adolescents with severe obesity identified that planning ahead, social support, and intrapersonal changes (e.g. self-confidence) can promote engagement in MRT. On the other hand, unplanned schedule changes, social pressures, and different intrapersonal factors (e.g., taste preference) can make engagement challenging.

CONCLUSIONS

Adolescents provided information on factors that supported or hindered their engagement in MRT, and themes were consistent with prior literature on health behaviour change. Overall, adolescents would recommend MRT to other teenagers who carry extra weight. Future research can use the rich information provided by adolescents with severe obesity to enhance and individualize treatment options.

General and Food-Specific Impulsivity and Inhibition Related to Weight Management

Background: Understanding child characteristics that relate to weight management treatment outcome could help identify opportunities for intervention innovation or tailoring. The limited evidence available is inconsistent regarding whether and which aspects of children's general or food-specific impulsivity and inhibition relate to treatment outcomes. Methods: Children with (n = 54) and without obesity (n = 22) were compared on various measures of impulsivity and inhibition. Children with obesity (n = 40) then completed family-based treatment for weight management. Analyses examined associations between baseline children's impulsivity and inhibition and child weight status change (BMI z-score) and between treatment-based changes in impulsivity and inhibition and weight status change, with and without adjustment by baseline functional magnetic resonance imaging-measured appetitive drive. Results: Children with obesity scored more poorly on some, but not all, measures of impulsivity and inhibition than children without obesity. Lower baseline general inhibition and greater parent-report of child impulsivity were associated (independently) with greater improvements in child weight status, with modest attenuation after appetite drive adjustment. Children improved task-based general inhibition during treatment. Improvements in general inhibition and snack food discounting were associated with better child weight outcomes, although adjusting for baseline values attenuated these associations. Conclusions: Children with obesity having greater initial impulsivity had better weight outcomes in treatment even after adjusting for initial appetitive drive. In contrast, improvements in task-based inhibition and food-related discounting during treatment were also related to better outcomes. Research is needed on innovative approaches to better address impulsivity and inhibition in children's weight management. Clinical Trial Registration number: NCT02484976.

The effect of personal relative deprivation on food choice: An experimental approach

Growing evidence suggests that relative disadvantage is more relevant than absolute socioeconomic factors in explaining disparities in healthfulness of diet. In a series of pre-registered experiments, we tested whether personal relative deprivation (PRD), i.e. the sense that one is unfairly deprived of a deserved outcome relative to others, results in choosing more palatable, rewarding foods. Study 1 (N = 102) demonstrated the feasibility and effectiveness of a game for inducing real-time experiences of PRD. Study 2 (N = 287) showed no main effect of PRD condition on hypothetical food choices, but an interaction between chronic PRD and condition revealed that those in the PRD condition chose more rewarding foods when feeling chronically deprived. In Study 3 (N = 260) the hypothesized main effect was found on real, non-hypothetical food choices: those in the PRD condition chose more rewarding foods, controlling for sensitivity to palatable food. Our results provide preliminary indications that the experience of being relatively deprived, rather than the objective amount or resources, may result in a higher preference for high-caloric and palatable foods. It may be suggested that efforts to reduce societal disparities in healthfulness of diet may need to focus on perceptions of injustice beyond objective inequalities.

Temporal discounting as a candidate behavioral marker of obesity

Although obesity is a result of processes operating at multiple levels, most forms result from decision-making behavior. The aim of this review was to examine the candidacy of temporal discounting (TD) (i.e. the reduction in the value of a reinforcer as a function of the delay to its receipt) as a behavioral marker of obesity. For this purpose, we assessed whether TD has the ability to: identify risk for obesity development, diagnose obesity, track obesity progression, predict treatment prognosis/outcomes, and measure treatment effectiveness. Three databases (Pubmed, PsycINFO, and Web of Science) were searched using a combination of terms related to TD and obesity. A total of 153 papers were reviewed. Several areas show strong evidence of TD's predictive utility as a behavioral marker of obesity (e.g., distinguishing obese from non obese). However, other areas have limited and/or mixed evidence (e.g., predicting weight change). Given the positive relationship for TD in the majority of domains examined, further consideration for TD as a behavioral marker of obesity is warranted.

Improving Serious Games to Tackle Childhood Obesity

Childhood obesity has become a global public health issue. Today, there are opportunities to promote health through technological devices such as serious games. Despite the major advancement of this field of research, the use of serious games as a validated intervention in clinical practice requires further clarifications on some methodological aspects. In this perspective article, we report the pros and cons of existing serious games. Besides, we attempt to propose a new methodology of design of a serious game that could help to cope with childhood obesity. The proposed idea consists of a serious game in virtual reality based on enjoyment, movement, education, and executive functioning (EF) training. Longitudinal studies and solid research protocol would certainly ensure consistency and aid interpretation.

Effects of a psychosocial intervention at one-year follow-up in a PREDIMED-plus sample with obesity and metabolic syndrome

This study examines if overweight/obesity are related to higher impulsivity, food addiction and depressive symptoms, and if these variables could be modified after 1 year of a multimodal intervention (diet, physical activity, psychosocial support). 342 adults (55-75 years) with overweight/obesity and metabolic syndrome (MetS) from the PREDIMED-Plus Cognition study were randomized to the intervention or to the control group (lifestyle recommendations). Cognitive and psychopathological assessments were performed at baseline and after 1-year follow-up. At baseline, higher impulsivity was linked to higher food addiction and depressive symptoms, but not to body mass index (BMI). Food addiction not only predicted higher BMI and depressive symptoms, but also achieved a mediational role between impulsivity and BMI/depressive symptoms. After 1 year, patients in both groups reported significant decreases in BMI, food addiction and impulsivity. BMI reduction and impulsivity improvements were higher in the intervention group. Higher BMI decrease was achieved in individuals with lower impulsivity. Higher scores in food addiction were also related to greater post-treatment impulsivity. To conclude, overweight/obesity are related to higher impulsivity, food addiction and depressive symptoms in mid/old age individuals with MetS. Our results also highlight the modifiable nature of the studied variables and the interest of promoting multimodal interventions within this population.

Effect of obesity on inhibitory control in preadolescents during stop-signal task. An event-related potentials study

Preadolescence is a period in which structural and functional changes occur in brain network reorganization that relate to the development of executive control functions, particularly in the areas of attention and cognitive inhibition. Obesity has been associated with a deficit in executive functions and behavioral and electrophysiological differences using the go/no-go task (proactive inhibition), but no study has assessed brain-electrical activity using the stop-signal task (reactive inhibition) in this population. Therefore, we hypothesized that obese preadolescents would show less efficiency in reactive inhibition than their same-age non-obese peers. To test this hypothesis, event-related potentials (ERPs) were collected during a stop-signal task and compared between 27 obese preadolescents (mean BMI = 25.9; 9.65 years old) and 29 normal-weight preadolescents (mean BMI = 17.5; 9.60 years old). No significant differences between groups were observed in behavioral responses. As for ERPs, the obese group had an electrophysiological pattern associated with less efficient conflict monitoring during the "no-go" condition (i.e., less modulation of N200 latency based on the experimental condition), differences in attentional allocation in the "go" condition (less modulation of P300a latency based on experimental condition), and difficulties in rule retrieval from working memory associated with the trial-type in both experimental conditions (smaller P300b amplitude). We conclude that obese preadolescents displayed less ability to modulate conflict-monitoring in the "no-go" condition and attention allocation in the "go" condition, evidencing differences between groups in the development of attention and inhibitory control.

The Combined Effects of Obesity and Cardiorespiratory Fitness Are Associated with Response Inhibition: An ERP Study

Obesity and cardiorespiratory fitness exhibit negative and positive impacts, respectively, on executive function. Nevertheless, the combined effects of these two factors on executive function remain unclear. This study investigated the combined effects of obesity and cardiorespiratory fitness on response inhibition of executive function from both behavioral and neuroelectric perspectives. Ninety-six young adults aged between 18 and 25 years were recruited and assigned into four groups: the high cardiorespiratory fitness with normal weight (NH), high cardiorespiratory fitness with obesity (OH), low cardiorespiratory fitness with normal weight (NL), and low cardiorespiratory fitness with obesity (OL) groups. The stop-signal task and its induced P3 component of event-related potentials was utilized to index response inhibition. The participants with higher cardiorespiratory fitness (i.e., the NH and OH groups) demonstrated better behavioral performance (i.e., shorter response times and higher accuracy levels), as well as shorter stop-signal response times and larger P3 amplitudes than their counterparts with low cardiorespiratory fitness (i.e., the NL and OL groups). The study provides first-hand evidence of the substantial effects of cardiorespiratory fitness on the response inhibition, including evidence that the detrimental effects of obesity might be overcome by high cardiorespiratory fitness.

The impact of impulsivity on weight loss after bariatric surgery: a systematic review

BACKGROUND

Impulsivity has been shown to be associated with obesity through links to pathological eating behavior such as binge eating. The recent literature suggests that impulsivity is linked to poorer outcomes post-bariatric surgery. Impulsivity can be measured in various ways and comprises of three broad domains: impulsive choice, impulsive action, and impulsive personality traits. The aim of this systematic review is to synthesize the current evidence on the impact of impulsivity on post-bariatric surgery weight loss.

METHODS

A literature review was performed in February 2020. Original studies investigating the relationship between impulsivity and weight loss post-bariatric surgery were evaluated.

RESULTS

Ten studies with a total of 1246 patients were analyzed. There were four case-control, four prospective observational and two retrospective observational studies. The postoperative follow-up ranged from 0.5 to 12 years. Eight studies measuring trait impulsivity did not show any association with weight loss post-bariatric surgery, although two studies reported an indirect effect of impulsivity on weight loss mediated via pathological eating behavior. Assessment of impulsive action by two studies showed that post-bariatric surgery weight loss is affected by impulsive action.

CONCLUSION

Impulsivity may adversely affect postoperative outcomes after bariatric surgery. However, this may be specific to state impulsivity or impulsive action rather than trait impulsivity. Patients with a higher state impulsivity may benefit from closer follow-up post-bariatric surgery, as well as cognitive behavioral therapies targeting cognitive control over food.

LEVEL OF EVIDENCE

Level I, systematic review.

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

While previous studies have suggested that there exists a relationship between obesity and executive function (EF), the mechanisms and causal relationship between them remain unclear. There are important clinical implications of determining whether EF can predict and treat obesity. We conducted a multilevel meta-analysis of randomized controlled trials (RCTs) and longitudinal studies. Specifically, we investigate (a) whether EF interventions have an effect on weight loss, (b) whether baseline EF can be a predictor of future weight loss through obesity intervention, and (c) whether early-life EF can predict future weight loss. Eight RCTs and 17 longitudinal studies with a total of 11,393 participants were identified. We found that (a) EF interventions may not have an effect on weight loss, (b) baseline inhibition (β = 0.259, p = 0.03) and delay discounting (β = −0.17, p = 0.04) significantly predict future weight loss through obesity intervention, (c) age (F = 13.666, p = 0.005) moderates the relationship between working memory and weight loss through intervention, but not weight status, type of intervention, and percentage of female, and (d) early life inhibition (β = 0.185, p = 0.07) is a marginally significant predictor of future weight loss. Our results seem to support the assumption that the relationship between EF and obesity is not direct, and a higher-order factor, such as genes, may link obesity and EF. Building on the preliminary findings, further studies focusing on EF and obesity are needed in the future.

Executive function in individuals with clinically significant weight loss via behavioral intervention

BACKGROUND

Executive function (EF) is associated with obesity development and self-management. Individuals who demonstrate or self-report poorer EF performance tend to have poorer short-term outcomes in obesity treatment. There may be distinct behavioral self-management strategies and EF domains related to initial weight loss as compared to weight loss maintenance.

OBJECTIVE

To characterize EF in individuals who achieved clinically significant weight loss via behavioral intervention and examine potential differences in EF between those who maintained versus regained lost weight.

METHODS

Participants who previously achieved ≥5% weight loss via lifestyle intervention were included (N = 44). "Maintainers" (n = 16) maintained this minimum level of weight loss for ≥1 year. "Regainers" (n = 28) regained some or all initially lost weight. Performance-based EF, intelligence quotient, health literacy, depression, anxiety, binge eating, demographics, and medical/weight history were assessed using a cross-sectional design. Descriptive statistics and age-, gender-, education-adjusted reference ranges were used to characterize EF. Analyses of covariance were conducted to examine EF differences between maintainers and regainers.

RESULTS

The sample consisted primarily of females with obesity over age 50. Approximately half self-identified as African-American. Decision-making performance was better in maintainers than regainers (p = 0.003, partη2 = 0.19). There were no differences between maintainers and regainers in inhibitory control, verbal fluency, planning/organization, cognitive flexibility, or working memory (ps > 0.05, partη2s = 0.003-0.07). At least 75% of the sample demonstrated average-above average EF test performance, indicated by scaled scores ≥13 or t-scores > 60.

CONCLUSIONS

Most individuals with obesity who achieved clinically significant weight loss via behavioral intervention had average to above average EF. Individuals who maintained (vs. regained) their lost weight performed better on tests of decision-making.

Cognitive remediation-enabled cognitive behaviour therapy for obesity: a case series

PURPOSE

Despite varied treatment effects, weight recidivism is common and typically associated with the abandonment of prescribed weight management strategies. Literature suggests that difficulty with weight management is associated with deficits in executive functioning, in particular cognitive flexibility and response inhibition, the neurocognitive processes that are involved in goal-directed behaviours, such as dietary adherence. These processes are overlooked by mainstream weight loss programmes. The aim of the study was to assess the effectiveness of a cognitive remediation-enabled cognitive behaviour therapy (CR-CBT) in addressing the neurocognitive, psychological and behavioural correlates of weight loss. It was hypothesised that CR-CBT would improve cognitive flexibility and response inhibition, reduce binge eating, aid weight loss and improve metabolic health.

METHODS

Four adults with obesity (body mass index > 30 kg/m²) received 7 weeks of manualised CR-CBT and were assessed via a case series analysis at baseline, end of treatment and 3-month follow-up. Treatment included 3 weekly 90-min group-based behaviour weight loss sessions for 3 weeks, followed by twice-weekly 50-min individualised CR-CBT sessions for 4 weeks.

RESULTS

Cognitive remediation-enabled cognitive behaviour therapy produced improvements in response inhibition and cognitive flexibility, and reductions in binge eating frequency, weight, and metabolic health readings between baseline and 3-month follow-up.

CONCLUSIONS

This is the first study to assess the effectiveness of CR-CBT in the treatment of obesity. Preliminary indications of treatment success are discussed with respect to study limitations. In light of these results, we recommend further investigation via a randomised control trial (RCT).

LEVEL OF EVIDENCE

Level IV, case series.

Effects of physical activity interventions on cognitive performance of overweight or obese children and adolescents: a systematic review and meta-analysis

BACKGROUND

Physical activity (PA) and obesity were linked with poor cognition. Our study assessed PA interventions could improve domain-specific cognition among overweight/obese youth.

METHODS

Systematically searched PubMed to identify relevant studies published up to October 2019. Standardized mean differences (SMD) of pre-post intervention were calculated in meta-analysis. The level of study heterogeneity represented by I² was interpreted as small (I² ≤ 25%), moderate (25% < I² ≤ 50%), substantial (50% < I² ≤ 75%), or considerable (I² > 75%).

RESULTS

Seventeen studies met the inclusion criteria; eight were included in the meta-analysis. Meta-analysis revealed that PA interventions improved core executive functions (core-EFs) (SMD = 0.301; 95% CI = 0.002-0.600; I²% = 80.6%) and non-EFs (SMD = 0.159; 95% CI = 0.029-0.289; I²% = 0.0%), but not metacognition and academic performance. Core-EFs benefited from enriched PA (SMD = 0.535; 95% CI = 0.020-1.051; I²% = 72.0%) and enhanced and enriched PA (SMD = 1.005; 95% CI = 0.017-1.993; I²% = 90.8%) interventions, while the non-EFs benefited more from enhanced PA (SMD = 0.166; 95% CI = 0.018-0.314; I²% = 0.0%). Interventions with a favorable effect on adiposity measures resulted in a significantly greater improvement in core-EFs (SMD = 0.438; 95% CI = 0.047-0.829; I²% = 58.8%) than those with no effects.

CONCLUSIONS

PA interventions can improve several domains of cognition, especially core-EFs and non-EFs, and the effects are affected by PA characteristics among overweight and obese youth.

IMPACT

Our study is the first to quantify the effect of PA interventions on CP among overweight or obese children and adolescents. Physical activity interventions positively affect cognitive performance, especially core executive functions (core-EFs) and non-EFs. Physical activity interventions seem to not positively affect metacognition (higher-level EFs and cognitive life skills) and academic performance. Physical task characteristics could influence the effect of chronic exercise on cognitive performance. Short-term physical activity programs may be particularly beneficial to affect core-EFs.

Cognitive Training: Associations and Implications for Weight Management and Translational Research

Behavioral weight loss programs combining energy restriction and increased physical activity (PA) are generally successful in producing clinically significant weight loss (≥5%) over 3-6 mos. However, weight maintenance (≥ 2 yrs.) continues to be problematic, due in part to an inability of individuals to continue adherence to diet and PA recommendations. It is hypothesized that neurocognitive processes, specifically executive functions (EFs, i.e., inhibition, working memory, mental flexibility), underlie self-regulation, self-efficacy, and are essential for the adoption and maintenance of health behaviors. Behavioral weight loss programs generally attempt to improve self-regulation; however, these skills are difficult to implement long-term. Strengthening EFs through cognitive training may improve weight maintenance by improving self-efficacy and self-regulation, resulting in improved program attendance and improved adherence to dietary and PA recommendations. Although randomized trials have not been conducted to specifically evaluate this hypothesis, results from the available literature suggest the potential for cognitive training to improve weight maintenance.

Oxytocin Administration Increases Proactive Control in Men with Overweight or Obesity: A Randomized, Double-Blind, Placebo-Controlled Crossover Study

OBJECTIVE

Preclinical and clinical evidence suggests that oxytocin administration decreases food intake and weight. The mechanisms underlying the anorexigenic effects of oxytocin in humans are unknown but critical to study to consider oxytocin as a neurohormonal weight loss treatment. Complementing ongoing research into metabolic and food motivation mechanisms of oxytocin, this study hypothesized that in humans, oxytocin improves cognitive control over behavior.

METHODS

In a randomized, double-blind, placebo-controlled crossover study of 24-IU single-dose intranasal oxytocin, 10 men with overweight or obesity completed a stop-signal task assessing ability and strategy to suppress behavioral impulses, in which they performed a choice-reaction task (go task) but had to withhold their response when prompted (stop task). It was hypothesized that oxytocin would improve suppression of behavioral impulses.

RESULTS

After receiving oxytocin, compared with placebo, participants showed increased reaction times in the go task (mean [M] = 936 milliseconds vs. 833 millseconds; P = 0.012; 95% CI: 29 to 178) and displayed fewer stop errors (M = 36.41% vs. 41.15%; P = 0.049; 95% CI: -9.43% to -0.03%).

CONCLUSIONS

Oxytocin triggers increased proactive control over behavior. Future studies need to further characterize the impact of oxytocin on cognitive control and investigate its potential role in the anorexigenic effects of oxytocin in human obesity.

Food reward sensitivity, impulsivity, and weight change during and after a 3-month weight loss program

Background

Greater sensitivity to food rewards and higher levels of impulsivity (and an interaction between these variables, termed “reinforcement pathology”) have been associated with obesity in cross-sectional studies. Less is known regarding how these constructs may impact attempts at weight loss or longer-term weight loss maintenance.

Methods

We provided 75 adults (69%Female, 84%White, age = 50.8y, BMI = 31.2kg/m²) with a 3-month Internet-based weight loss program and assessed weight, food reward sensitivity (via the Power of Food Scale [PFS]), and impulsivity (via Go No-Go [GNG] and Delay Discounting [DD] computer tasks) at baseline and at Months 3, 6, 9, and 12. No additional intervention was provided Months 3–12. Multi-level mixed-effect models were used to examine changes in PFS, GNG, and DD over time and associations between these measures and weight loss/regain.

Results

Participants lost 6.0±1.1kg Months 0–3 and regained 2.4±1.1kg Months 3–12. Across time points, higher PFS scores were associated with higher weight, p = .007; however, there were no significant associations between GNG or DD and weight nor between the interactions of PFS and GNG or DD and weight, ps>.05. There were significant decreases from Months 0–3 in PFS, GNG, and DD, ps < .05; however, neither baseline values nor changes were significantly associated with weight change and there were no significant associations between the interactions of PFS and GNG or DD and weight change, ps>.05.

Conclusion

Results demonstrated an association between food reward sensitivity and weight. Further, decreases in both food reward sensitivity and impulsivity were observed during an initial weight loss program, but neither baseline levels nor improvements were associated with weight change. Taken together, results suggest that the constructs of food reward sensitivity, impulsivity, and reinforcement pathology may have limited clinical utility within behavioral weight management interventions. Future intervention studies should examine whether food-related impulsivity tasks lead to a similar pattern of results.

Implicit food odour priming effects on reactivity and inhibitory control towards foods

The food environment can interact with cognitive processing and influence eating behaviour. Our objective was to characterize the impact of implicit olfactory priming on inhibitory control towards food, in groups with different weight status. Ninety-one adults completed a modified Affective Shifting Task: they had to detect target stimuli and ignore distractor stimuli while being primed with non-attentively perceived odours. We measured reactivity and inhibitory control towards food pictures. Priming effects were observed on reactivity: participants with overweight and obesity were slower when primed with pear and pound cake odour respectively. Common inhibitory control patterns toward foods were observed between groups. We suggest that non-attentively perceived food cues influence bottom-up processing by activating distinguished mental representations according to weight status. Also, our data show that cognitive load influences inhibitory control toward foods. Those results contribute to understanding how the environment can influence eating behaviour in individuals with obesity.

Emotion regulation strategies predict weight loss during an inpatient obesity treatment for adolescents

Objective

Weight loss during an inpatient obesity treatment is an important predictor of subsequent weight maintenance. However, psychological factors influencing weight loss are not well established. Psychological models suggest some importance of executive functioning and emotion regulation strategies. Therefore, this study investigated whether these factors predict weight loss during an inpatient obesity treatment and whether this effect holds after controlling for general personal and treatment characteristics.

Method

A total of 158 adolescents with diagnosed obesity underwent inpatient obesity treatment at a German rehabilitation clinic. Psychological factors (executive functioning and emotion regulation) were measured at admission and used to predict BMI reduction after treatment completion.

Results

More frequent use of reappraisal as an emotion regulation strategy, but not suppression or executive functioning, predicted weight loss at the end of the obesity treatment, even after controlling for age, gender, treatment duration, and BMI at admission.

Conclusion

Functional emotion regulation strategies, like reappraisal, might offer an additional target for obesity treatment programmes, complementary to the more traditional components of psychoeducation, physical activity, and caloric restriction.

Role of Motor Competence and Executive Functioning in Weight Loss: A Study in Children with Obesity

OBJECTIVE

This study aimed to compare motor competence and executive functioning (EF) between children with obesity and peers with healthy weight. Additionally, the predictive value of motor competence and EF in weight loss after a 5-month multidisciplinary residential treatment program was examined.

METHODS

Thirty-two children with obesity (7-11 years, 14 boys) and 32 age-matched controls (18 boys) performed 8 motor skill tasks and 4 tasks of EF (only at baseline). In the group of children with obesity, anthropometric measurements were performed at baseline and 5 months after the start of their treatment program. Also in control children, there was a time span of 5 months in between anthropometric measurements.

RESULTS

Lower levels of motor competence and reduced updating abilities, inhibition control, and planning skills were observed in children with obesity compared with healthy-weight controls. Within the total group, better general motor competence and balance skills were significantly associated with better updating, inhibition control, and planning. Finally, hierarchical regression analyses revealed that ball skills, balance skills, and inhibition/updating at baseline predicted 14% to 17% of the variance in weight loss after a 5-month treatment program in children with obesity.

CONCLUSION

These results suggest that motor competence and EF are both relevant factors associated with childhood obesity. Moreover, these factors seem to be significant predictors of weight loss. Future (intervention) studies are needed to understand the impact of the difficulties in motor and EF on obesity-related behaviors as well as on short-term and, especially, long-term weight loss and maintenance.

Longer-term liraglutide administration at the highest dose approved for obesity increases reward-related orbitofrontal cortex activation in response to food cues: Implications for plateauing weight loss in response to anti-obesity therapies

AIMS

GLP-1 analogs have recently risen to the forefront as effective medications for lowering weight through actions in the central nervous system (CNS). However, their actions in the CNS have not yet been studied in the human brain after longer-term administration at the highest dose approved for obesity (liraglutide 3.0 mg).

MATERIALS AND METHODS

A total of 20 participants with obesity were treated with placebo and liraglutide (3.0 mg) in the context of a randomized, placebo-controlled, double-blind, cross-over trial after 5 weeks of dose escalation. Neurocognitive and neuroimaging (fMRI) responses to food cues were examined at the clinical research center of Beth Israel Deaconess Medical Center.

RESULTS

While using liraglutide, patients lost more weight (placebo-subtracted -2.7%; P < .001), had decreased fasting glucose (P < .001) and showed improved cholesterol levels. In an uncontrolled analysis, brain activation in response to food images was not altered by liraglutide vs placebo. When controlled for BMI/weight, liraglutide increased activation of the right orbitofrontal cortex (OFC) in response to food cues (P < .016, corrected for multiple comparisons).

CONCLUSIONS

In contrast to prior studies, we demonstrate for the first time that liraglutide treatment, administered over a longer period at the highest doses approved for obesity, does not alter brain activation in response to food cues. A counter-regulatory increase in reward-related OFC activation in response to food cues can be observed when neuroimaging data are controlled for BMI changes, indicating changes in CNS that could lead to later plateaus of weight loss. These data point to a promising focus for additional interventions which, by contributing to the CNS reward system, could provide tangible benefits in reversing the plateauing phenomenon and promoting further weight loss.

The Executive Functions in Overweight and Obesity: A Systematic Review of Neuropsychological Cross-Sectional and Longitudinal Studies

Background: The increasing incidence of people affected by overweight or obesity is a significant health problem. The knowledge of the factors which influences the inappropriate eating behaviors causing excessive body fat is an essential goal for the research. Overweight and obesity are significant risk factors for many health diseases, such as cardiovascular problems, diabetes. Recently, many studies have focused on the relationship between body weight and cognitive processes. Objectives: This systematic review is aimed to investigate the existence and the nature of the relationship between excessive body weight (overweight/obesity) and executive functions, analyzing cross-sectional, and longitudinal studies in order to verify the evidence of a possible causality between these variables. Methods: The review was carried out according to the PRISMA-Statement, through systematic searches in the scientific databases PubMed, Medline, PsychInfo, and PsycArticles. The studies selected examined performance on executive tasks by participants with overweight or obesity, aged between 5 and 70 years. Studies examining eating disorders or obesity resulting from other medical problems were excluded. Furthermore, the results of studies using a cross-sectional design and those using a longitudinal one were separately investigated. Results: Sixty-three cross-sectional studies and twenty-eight longitudinal studies that met our inclusion and exclusion criteria were analyzed. The results confirmed the presence of a relation between executive functions and overweight/obesity, although the directionality of this relation was not clear; nor did any single executive function emerge as being more involved than others in this relation. Despite this, there was evidence of a reciprocal influence between executive functions and overweight/obesity. Conclusions: This systematic review underlines the presence of a relationship between executive functions and overweight/obesity. Moreover, it seems to suggest a bidirectional trend in this relationship that could be the cause of the failure of interventions for weight reduction. The results of this review highlight the importance of a theoretical model able to consider all the main variables of interest, with the aim to structuring integrated approaches to solve the overweight/obesity problems.

Executive Function, Eating Behavior, and Preoperative Weight Loss in Bariatric Surgery Candidates: An Observational Study

BACKGROUND

Individual differences in executive function may influence eating behavior, weight loss (WL), and WL maintenance in obesity treatment. Executive function, which designates top-down cognitive control processes, has been related to eating behaviors which may impact weight, and has been found to be predictive of WL in both behavioral WL programs and after bariatric surgery. Currently, we lack knowledge on the role of executive function in the period before bariatric surgery. If executive function impacts eating behavior and WL in the preoperative period, it may be a target for clinical attention in this stage.

OBJECTIVES

We aimed to examine the relationship between objective performance-based measures of executive function, eating patterns, and WL in the preoperative period.

METHOD

Baseline data in an ongoing observational longitudinal study of bariatric surgery patients were used. Eighty patients completed neuropsychological testing and self-report questionnaires 4 weeks prior to surgery.

RESULTS

We found that working memory predicted WL before surgery and inhibitory control predicted adherence to dietary recommendations.

CONCLUSION

Our study indicates that executive function may play a role in short-term WL and dietary adherence prior to surgery, suggesting that executive function in the preoperative period deserves an extended research focus.

Exploring the evidence base for Tier 3 specialist weight management interventions for children aged 2-18 years in the UK: a rapid systematic review

Background

The impact of specialist weight management services (Tier 3) for children with severe and complex obesity in the UK is unclear. This review aims to examine the impact of child Tier 3 services in the UK, exploring service characteristics and implications for practice.

Methods

Rapid systematic review of any study examining specialist weight management interventions in any UK setting including children (2-18 years) with a body mass index >99.6th centile or >98th centile with comorbidity.

Results

Twelve studies (five RCTs and seven uncontrolled) were included in a variety of settings. Study quality was moderate or low and mean baseline body mass index z-score ranged from 2.7 to 3.6 units. Study samples were small and children were predominantly older (10-14 years), female and white. Multidisciplinary team composition and eligibility criteria varied; dropout ranged from 5 to 43%. Improvements in zBMI over 1-24 months ranged from -0.13 to -0.41 units.

Conclusions

Specialist weight management interventions for children with severe obesity demonstrated a reduction in zBMI, across a variety of UK settings. Studies were heterogeneous in content and thus conclusions on service design cannot be drawn. There is a paucity of evidence for Tier 3 services for children, and further research is required.

Weight loss, behavioral change, and structural neuroplasticity in children with obesity through a multidisciplinary treatment program

This study evaluated the effect of a multidisciplinary treatment program for children with obesity (OB) on motor competence, executive functioning (EF), and brain structure. Nineteen children with OB (7-11 years), who attended a multidisciplinary treatment program consisting of diet restriction, cognitive behavioral therapy, and physical activity, were compared with an age-matched control group of 24 children with a healthy weight (HW), who did not follow any treatment. For both groups, anthropometric measurements and tests of motor competence and EF were administered twice, with 5 months between pretest and posttest. Additionally, children's brain structure was assessed by performing a magnetic resonance imaging (MRI) scan at the pretest and posttest, which included a T1 anatomical scan, diffusion MRI scan, and magnetization transfer imaging scan. Compared to HW controls, children with OB lost a considerable amount of their body mass (p ≤ .001) and significantly improved their balance skills (p ≤ .001), while no transfer effects of the program were observed for EF. Furthermore, the program resulted in a significant increase in total (p ≤ .001) and cerebellar (p ≤ .001) gray matter volume in children with OB, while no change was observed in the HW controls. Finally, only weak to moderate (nonsignificant) correlations could be observed between structural brain alterations, weight-related changes, and behavioral improvements. Altogether, this is the first longitudinal study showing behavioral and structural brain alterations in response to a multidisciplinary weight loss program for children with OB. Our findings support the need for multidimensional intervention (and prevention) measures for children with OB to deal with this multifactorial health problem.

WELCOME: improving WEight controL and CO-Morbidities in children with obesity via Executive function training: study protocol for a randomized controlled trial

BACKGROUND

Obesity is a widespread problem that not only leads to medical and psychological diseases in adults, but also in children and adolescents at an early stage in life. Because of its global burden on both the individual and society, it is necessary to develop effective evidence-based treatments. Current "Multidisciplinary Obesity Treatments" (MOT) already provide significant weight loss, but still leave room for more long-lasting improvements. In this protocol paper, we outline the research goals of the WELCOME trial, based on a substantial proof of concept.

METHODS

In this Randomized Controlled Trial (RCT) - conducted in both an inpatient and two outpatient treatment settings - existing MOT will be supplemented with an Executive Function (EF) training and compare effects on various parameters in an experimental versus an active control group of obese youngsters (8-18 years old). WELCOME aims to (a) train youngsters' executive functions to facilitate effects on weight loss, psychological and medical comorbidities, (b) to enhance the long-term effects by continuing the training in the daily home context with booster sessions, and (c) to investigate its effects until a 6-month follow-up. In comparison to the active control group, better progress is expected in the experimental group on following variables: weight, psychological comorbidities (unhealthy eating behavior, internalizing symptoms, impaired self-esteem) and medical comorbidities (metabolic syndromes, endothelia dysfunction, tonsillar hypertrophy and sleep obstruction).

DISCUSSION

It is stated that this EF-training for enhancing self-control abilities is necessary for a long-lasting effect of childhood obesity treatment interventions.

TRIAL REGISTRATION

The Study Procotol was registered on 10/05/2017 (n° ISRCTN14722584 ).

Improved cognitive functioning in obese adolescents after a 30-week inpatient weight loss program

INTRODUCTION

Studies linked obesity with a large number of medical conditions including decreased cognitive functioning. The relation between BMI and cognition was proven in adults, but in adolescents the results are conflicting. Further, limited data are available on the impact of weight loss on cognition. This study analyzed the impact of a 30-week lasting weight loss program on cognition and determined the impact of changes in body composition and self-perceived fatigue on changes in cognition.

METHODS

Sixty-two obese adolescents were evaluated at baseline and after 30 weeks. Stroop test (ST; selective attention), Continuous Performance Test (CPT; sustained attention) and Ray Auditory verbal learning test (RAVLT; short-term memory) were assessed. Additionally, body composition parameters and fatigue (MFI-20) were evaluated.

RESULTS

Improved reaction times were found for ST and CPT after the intervention, but were independent for reductions in BMI, fat mass, fat%, and fatigue. Short memory also improved with decreased fatigue as an influencing parameter. Accuracy of ST and CPT showed no significant changes.

CONCLUSION

A 30-week lasting inpatient weight loss program improved selective attention, sustained attention, and short-term memory. Changes in body composition did not explain the improvements in cognitive functioning. Decreased fatigue resulted in improved aspects of cognition.

Executive and Reward-Related Function in Pediatric Obesity: A Meta-Analysis

OBJECTIVE

This study examined the effect of pediatric obesity on executive function and reward-related decision-making, cognitive processes that are relevant to obesogenic behaviors, and evaluated their association with sample (e.g., age, gender, intelligence, and socioeconomic status, SES) and study/task (e.g., categorical/continuous variable, food stimuli) characteristics.

METHODS

A random-effects meta-analysis was conducted using Hedge's g effect sizes of published studies from 1960 to 2016, limited to children younger than the age of 21 years without medical comorbidities. Analysis included estimation of heterogeneity (τ²), publication bias (funnel-plot symmetry and fail-safe N), and sensitivity analyses for sample and study/task characteristics.

RESULTS

Across 68 studies with 70 samples, obesity was associated with worse functioning overall (-0.24; 95CI: -0.30 to -0.19; p < 0.001) and for each component process (attention, switching, inhibition, interference, working memory, reward, delay of gratification: -0.19 to -0.38; p's < 0.017), except trait impulsivity (-0.06; 95CI: -0.18 to 0.07). Deficits increased with age and female composition of the sample for inhibition (p = 0.002). No other characteristics moderated effect of obesity.

CONCLUSIONS

Small-to-moderate negative associations with obesity were observed for executive and reward-related performance, but not on reported impulsivity in studies with children younger than the age of 21 years. These results were not moderated by IQ, SES, and study/task characteristics. Age and gender moderated association with inhibition, with a larger obesity-related deficit in older and predominantly female samples. These results suggest cognitive and demographic intervention targets for prevention and mitigation of obesogenic behavior.

Feasibility and Effectiveness of Adding an Approach Avoidance Training With Game Elements to a Residential Childhood Obesity Treatment — A Pilot Study

Childhood obesity treatment programs only result in moderate outcomes in the short term and do not reduce risk for future weight gain. Therefore, in the current study, Approach Avoidance Training (AAT) with motivational game elements will be added to an inpatient childhood obesity program with the aim of improving outcomes. Forty-one children (10–15 years) in the final months of an inpatient treatment program were randomised to either the AAT plus care-as-usual condition group or to a care-as-usual-only control group. During the 10 sessions, the children were trained to approach healthy food stimuli and to avoid unhealthy food stimuli. Treatment outcomes were child performances on tasks of AAT, implicit attitudes and attentional bias, self-report ratings on craving symptoms, and weight loss maintenance after leaving the clinic (12-week follow-up). Changes over time were not significantly different between conditions for the measures of automatic processes, craving, and weight loss maintenance. Possible accounts for the null findings, including sample size, influence of game elements, point of time in therapeutic process, limitations of the setting, and the control group are discussed. More research is needed before firm conclusions can be drawn about the clinical usefulness of CBM for weight control in childhood obesity.

Executive function in childhood obesity: Promising intervention strategies to optimize treatment outcomes

Executive functions (EFs) are hypothesized to play a role in the development and maintenance of obesity due to their role in self-regulatory processes that manage energy-balance behaviors. Children with obesity have well-documented deficits in EF, which may impede effectiveness of current, evidence-based treatments. This review examines top-down EF processes (e.g., inhibitory control, working memory, cognitive flexibility), as well as bottom-up automatic processes that interact with EFs (e.g., attentional bias, delay discounting) and their relation to weight-loss treatment success in children. It then evaluates EF-related interventions that may improve treatment response. Empirical studies that included an intervention purported to affect EF processes as well as pre-post measurements of EF and/or relative weight in populations ages 19 or younger with overweight/obesity were reviewed. Findings indicate that poorer EF may hinder treatment response. Moreover, there is preliminary evidence that behavioral weight loss intervention and physical activity may positively affect EF and that improvements in EF are related to enhanced weight loss. Finally, novel intervention strategies, such as computer training of core EFs, attention modification programs, and episodic future thinking, show promise in influencing both EFs and EF-related skills and weight. Further research is needed to provide more conclusive evidence of the efficacy of these interventions and additional applications and settings should be considered.

Sleep Health and Psychopathology Mediate Executive Deficits in Pediatric Obesity

OBJECTIVE

Executive and motivational dysfunction have been associated with pediatric obesity. Poor sleep quality and psychopathology, often comorbid with obesity, are also associated with executive and motivational dysfunction. We examined the contribution of these comorbid factors to the association between obesity and executive function and reward-related decision-making.

METHODS

Seven- to 18-year-old children with and without obesity performed a working memory task with low and high loads, a response inhibition task, and a probabilistic reward-related decision-making task. Parents filled out standardized measures of executive function in everyday behavior, sleep health, and psychiatric symptoms. Analyses controlled for age, gender, IQ, and parental education.

RESULTS

Children with obesity showed worse working memory performance under higher load (p = 0.007), and worse parent-reported behavioral regulation (p = 0.05) and metacognition (p = 0.04) in everyday behavior and their reward-related decision-making was less consistent with learned probabilistic conditions (p = 0.04). Response inhibition did not differ between groups. Children with obesity had worse parent-reported sleep health (p < 0.01) and 4.27 greater odds of clinically relevant internalizing symptomology (p = 0.03), both of which mediated the effect of obesity on behavioral regulation (p's < 0.01) and metacognition (p's < 0.01). Performance-based assessments were not associated with sleep health or psychopathology.

CONCLUSIONS

Sleep quality and internalizing psychopathology were worse in children with obesity and contributed to parent-reported executive dysfunction in their everyday behavior. Performance-based measures of working memory and decision-making were not associated with those comorbidities of obesity.

Physical activity, diet and other behavioural interventions for improving cognition and school achievement in children and adolescents with obesity or overweight

BACKGROUND

The global prevalence of childhood and adolescent obesity is high. Lifestyle changes towards a healthy diet, increased physical activity and reduced sedentary activities are recommended to prevent and treat obesity. Evidence suggests that changing these health behaviours can benefit cognitive function and school achievement in children and adolescents in general. There are various theoretical mechanisms that suggest that children and adolescents with excessive body fat may benefit particularly from these interventions.

OBJECTIVES

To assess whether lifestyle interventions (in the areas of diet, physical activity, sedentary behaviour and behavioural therapy) improve school achievement, cognitive function (e.g. executive functions) and/or future success in children and adolescents with obesity or overweight, compared with standard care, waiting-list control, no treatment, or an attention placebo control group.

SEARCH METHODS

In February 2017, we searched CENTRAL, MEDLINE and 15 other databases. We also searched two trials registries, reference lists, and handsearched one journal from inception. We also contacted researchers in the field to obtain unpublished data.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials (RCTs) of behavioural interventions for weight management in children and adolescents with obesity or overweight. We excluded studies in children and adolescents with medical conditions known to affect weight status, school achievement and cognitive function. We also excluded self- and parent-reported outcomes.

DATA COLLECTION AND ANALYSIS

Four review authors independently selected studies for inclusion. Two review authors extracted data, assessed quality and risks of bias, and evaluated the quality of the evidence using the GRADE approach. We contacted study authors to obtain additional information. We used standard methodological procedures expected by Cochrane. Where the same outcome was assessed across different intervention types, we reported standardised effect sizes for findings from single-study and multiple-study analyses to allow comparison of intervention effects across intervention types. To ease interpretation of the effect size, we also reported the mean difference of effect sizes for single-study outcomes.

MAIN RESULTS

We included 18 studies (59 records) of 2384 children and adolescents with obesity or overweight. Eight studies delivered physical activity interventions, seven studies combined physical activity programmes with healthy lifestyle education, and three studies delivered dietary interventions. We included five RCTs and 13 cluster-RCTs. The studies took place in 10 different countries. Two were carried out in children attending preschool, 11 were conducted in primary/elementary school-aged children, four studies were aimed at adolescents attending secondary/high school and one study included primary/elementary and secondary/high school-aged children. The number of studies included for each outcome was low, with up to only three studies per outcome. The quality of evidence ranged from high to very low and 17 studies had a high risk of bias for at least one item. None of the studies reported data on additional educational support needs and adverse events.Compared to standard practice, analyses of physical activity-only interventions suggested high-quality evidence for improved mean cognitive executive function scores. The mean difference (MD) was 5.00 scale points higher in an after-school exercise group compared to standard practice (95% confidence interval (CI) 0.68 to 9.32; scale mean 100, standard deviation 15; 116 children, 1 study). There was no statistically significant beneficial effect in favour of the intervention for mathematics, reading, or inhibition control. The standardised mean difference (SMD) for mathematics was 0.49 (95% CI -0.04 to 1.01; 2 studies, 255 children, moderate-quality evidence) and for reading was 0.10 (95% CI -0.30 to 0.49; 2 studies, 308 children, moderate-quality evidence). The MD for inhibition control was -1.55 scale points (95% CI -5.85 to 2.75; scale range 0 to 100; SMD -0.15, 95% CI -0.58 to 0.28; 1 study, 84 children, very low-quality evidence). No data were available for average achievement across subjects taught at school.There was no evidence of a beneficial effect of physical activity interventions combined with healthy lifestyle education on average achievement across subjects taught at school, mathematics achievement, reading achievement or inhibition control. The MD for average achievement across subjects taught at school was 6.37 points lower in the intervention group compared to standard practice (95% CI -36.83 to 24.09; scale mean 500, scale SD 70; SMD -0.18, 95% CI -0.93 to 0.58; 1 study, 31 children, low-quality evidence). The effect estimate for mathematics achievement was SMD 0.02 (95% CI -0.19 to 0.22; 3 studies, 384 children, very low-quality evidence), for reading achievement SMD 0.00 (95% CI -0.24 to 0.24; 2 studies, 284 children, low-quality evidence), and for inhibition control SMD -0.67 (95% CI -1.50 to 0.16; 2 studies, 110 children, very low-quality evidence). No data were available for the effect of combined physical activity and healthy lifestyle education on cognitive executive functions.There was a moderate difference in the average achievement across subjects taught at school favouring interventions targeting the improvement of the school food environment compared to standard practice in adolescents with obesity (SMD 0.46, 95% CI 0.25 to 0.66; 2 studies, 382 adolescents, low-quality evidence), but not with overweight. Replacing packed school lunch with a nutrient-rich diet in addition to nutrition education did not improve mathematics (MD -2.18, 95% CI -5.83 to 1.47; scale range 0 to 69; SMD -0.26, 95% CI -0.72 to 0.20; 1 study, 76 children, low-quality evidence) and reading achievement (MD 1.17, 95% CI -4.40 to 6.73; scale range 0 to 108; SMD 0.13, 95% CI -0.35 to 0.61; 1 study, 67 children, low-quality evidence).

AUTHORS' CONCLUSIONS

Despite the large number of childhood and adolescent obesity treatment trials, we were only able to partially assess the impact of obesity treatment interventions on school achievement and cognitive abilities. School and community-based physical activity interventions as part of an obesity prevention or treatment programme can benefit executive functions of children with obesity or overweight specifically. Similarly, school-based dietary interventions may benefit general school achievement in children with obesity. These findings might assist health and education practitioners to make decisions related to promoting physical activity and healthy eating in schools. Future obesity treatment and prevention studies in clinical, school and community settings should consider assessing academic and cognitive as well as physical outcomes.

A Review of Childhood Behavioral Problems and Disorders in the Development of Obesity: Attention Deficit/Hyperactivity Disorder, Autism Spectrum Disorder, and Beyond

PURPOSE OF REVIEW

Given the high rates of pediatric and adult obesity, it is imperative to identify early risk factors that might contribute to excess weight gain. This review aims to investigate the relationship between childhood behavioral problems with the development and persistence of obesity. Specifically, this review highlights the association of obesity with (1) neurocognitive constructs, such as executive functioning and inhibition/impulsivity, and (2) disorders commonly diagnosed in childhood, including attention deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD).

RECENT FINDINGS

Consistent evidence supports a relationship between childhood behavioral problems, executive functioning, inhibition/impulsivity, ADHD, and ASD with obesity across the lifespan. Longitudinal studies suggest behavior problems, neurocognitive functioning deficits, and ADHD symptoms in childhood predict weight gain over time. Identifying risk factors in childhood that promote obesity may help develop targeted intervention and prevention programs. Additional research should elucidate mechanisms that account for these relationships.

Physical activity, diet and other behavioural interventions for improving cognition and school achievement in children and adolescents with obesity or overweight

BACKGROUND

The global prevalence of childhood and adolescent obesity is high. Lifestyle changes towards a healthy diet, increased physical activity and reduced sedentary activities are recommended to prevent and treat obesity. Evidence suggests that changing these health behaviours can benefit cognitive function and school achievement in children and adolescents in general. There are various theoretical mechanisms that suggest that children and adolescents with excessive body fat may benefit particularly from these interventions.

OBJECTIVES

To assess whether lifestyle interventions (in the areas of diet, physical activity, sedentary behaviour and behavioural therapy) improve school achievement, cognitive function (e.g. executive functions) and/or future success in children and adolescents with obesity or overweight, compared with standard care, waiting-list control, no treatment, or an attention placebo control group.

SEARCH METHODS

In February 2017, we searched CENTRAL, MEDLINE and 15 other databases. We also searched two trials registries, reference lists, and handsearched one journal from inception. We also contacted researchers in the field to obtain unpublished data.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials (RCTs) of behavioural interventions for weight management in children and adolescents with obesity or overweight. We excluded studies in children and adolescents with medical conditions known to affect weight status, school achievement and cognitive function. We also excluded self- and parent-reported outcomes.

DATA COLLECTION AND ANALYSIS

Four review authors independently selected studies for inclusion. Two review authors extracted data, assessed quality and risks of bias, and evaluated the quality of the evidence using the GRADE approach. We contacted study authors to obtain additional information. We used standard methodological procedures expected by Cochrane. Where the same outcome was assessed across different intervention types, we reported standardised effect sizes for findings from single-study and multiple-study analyses to allow comparison of intervention effects across intervention types. To ease interpretation of the effect size, we also reported the mean difference of effect sizes for single-study outcomes.

MAIN RESULTS

We included 18 studies (59 records) of 2384 children and adolescents with obesity or overweight. Eight studies delivered physical activity interventions, seven studies combined physical activity programmes with healthy lifestyle education, and three studies delivered dietary interventions. We included five RCTs and 13 cluster-RCTs. The studies took place in 10 different countries. Two were carried out in children attending preschool, 11 were conducted in primary/elementary school-aged children, four studies were aimed at adolescents attending secondary/high school and one study included primary/elementary and secondary/high school-aged children. The number of studies included for each outcome was low, with up to only three studies per outcome. The quality of evidence ranged from high to very low and 17 studies had a high risk of bias for at least one item. None of the studies reported data on additional educational support needs and adverse events.Compared to standard practice, analyses of physical activity-only interventions suggested high-quality evidence for improved mean cognitive executive function scores. The mean difference (MD) was 5.00 scale points higher in an after-school exercise group compared to standard practice (95% confidence interval (CI) 0.68 to 9.32; scale mean 100, standard deviation 15; 116 children, 1 study). There was no statistically significant beneficial effect in favour of the intervention for mathematics, reading, or inhibition control. The standardised mean difference (SMD) for mathematics was 0.49 (95% CI -0.04 to 1.01; 2 studies, 255 children, moderate-quality evidence) and for reading was 0.10 (95% CI -0.30 to 0.49; 2 studies, 308 children, moderate-quality evidence). The MD for inhibition control was -1.55 scale points (95% CI -5.85 to 2.75; scale range 0 to 100; SMD -0.15, 95% CI -0.58 to 0.28; 1 study, 84 children, very low-quality evidence). No data were available for average achievement across subjects taught at school.There was no evidence of a beneficial effect of physical activity interventions combined with healthy lifestyle education on average achievement across subjects taught at school, mathematics achievement, reading achievement or inhibition control. The MD for average achievement across subjects taught at school was 6.37 points lower in the intervention group compared to standard practice (95% CI -36.83 to 24.09; scale mean 500, scale SD 70; SMD -0.18, 95% CI -0.93 to 0.58; 1 study, 31 children, low-quality evidence). The effect estimate for mathematics achievement was SMD 0.02 (95% CI -0.19 to 0.22; 3 studies, 384 children, very low-quality evidence), for reading achievement SMD 0.00 (95% CI -0.24 to 0.24; 2 studies, 284 children, low-quality evidence), and for inhibition control SMD -0.67 (95% CI -1.50 to 0.16; 2 studies, 110 children, very low-quality evidence). No data were available for the effect of combined physical activity and healthy lifestyle education on cognitive executive functions.There was a moderate difference in the average achievement across subjects taught at school favouring interventions targeting the improvement of the school food environment compared to standard practice in adolescents with obesity (SMD 0.46, 95% CI 0.25 to 0.66; 2 studies, 382 adolescents, low-quality evidence), but not with overweight. Replacing packed school lunch with a nutrient-rich diet in addition to nutrition education did not improve mathematics (MD -2.18, 95% CI -5.83 to 1.47; scale range 0 to 69; SMD -0.26, 95% CI -0.72 to 0.20; 1 study, 76 children, low-quality evidence) and reading achievement (MD 1.17, 95% CI -4.40 to 6.73; scale range 0 to 108; SMD 0.13, 95% CI -0.35 to 0.61; 1 study, 67 children, low-quality evidence).

AUTHORS' CONCLUSIONS

Despite the large number of childhood and adolescent obesity treatment trials, we were only able to partially assess the impact of obesity treatment interventions on school achievement and cognitive abilities. School and community-based physical activity interventions as part of an obesity prevention or treatment programme can benefit executive functions of children with obesity or overweight specifically. Similarly, school-based dietary interventions may benefit general school achievement in children with obesity. These findings might assist health and education practitioners to make decisions related to promoting physical activity and healthy eating in schools. Future obesity treatment and prevention studies in clinical, school and community settings should consider assessing academic and cognitive as well as physical outcomes.

An Investigation of Executive Functioning in Pediatric Anxiety

Although science's understanding (e.g., etiology, maintaining factors, etc.) of pediatric anxiety and related problems has grown substantially over recent years, several aspects to anxiety in youths remain elusive, particularly with relation to executive functioning. To this end, the current study sought to examine several facets to executive functioning (i.e., cognitive flexibility, inhibition, planning, working memory) within a transdiagnostic sample of youths exhibiting varying degrees of anxiety symptoms. One hundred six youths completed a comprehensive battery, including several self-report measures (e.g., Multidimensional Anxiety Scale for Children [MASC] or MASC-2) and an automated neurocognitive battery of several executive functioning tasks (Intradimensional/Extradimensional [IDED], Stop Signal [SST], Spatial Span [SSP], Stockings of Cambridge [SOC] tasks). Regression analyses indicated that youths exhibiting marked anxiety symptoms demonstrated increased planning time and probability of inhibition compared with youths with minimal or no anxiety symptoms. Youths with marked anxiety symptoms similarly demonstrated better cognitive flexibility (i.e., set shifting) compared with youths with minimal anxiety. In addition, analyses indicated a trend such that youths exhibiting marked anxiety symptoms demonstrated poorer working memory compared with youths with no anxiety symptoms. Group classification did not predict remaining outcomes. Limitations and future areas of research are discussed.

An insulin resistance associated neural correlate of impulsivity in type 2 diabetes mellitus

Central insulin resistance (IR) influences striatal dopamine (DA) tone, an important determinant of behavioral self-regulation. We hypothesized that an association exists between the degree of peripheral IR and impulse control, mediated by the impact of IR on brain circuits controlling the speed of executing “go” and/or “stop” responses. We measured brain activation and associated performance on a stop signal task (SST) in obese adults with type 2 diabetes (age, 48.1 ± 6.9 yrs (mean ± SD); BMI, 36.5 ± 4.0 kg/m²; HOMA-IR, 7.2 ± 4.1; 12 male, 18 female). Increasing IR, but not BMI, was a predictor of shorter critical stop signal delay (cSSD), a measure of the time window during which a go response can be successfully countermanded (R² = 0.12). This decline was explained by an IR-associated increase in go speed (R² = 0.13) with little impact of IR or BMI on stop speed. Greater striatal fMRI activation contrast in stop error (SE) compared with stop success (SS) trials (CON_SE>SS) was a significant predictor of faster go speeds (R² = 0.33, p = 0.002), and was itself predicted by greater IR (CON_SE>SS vs HOMA-IR: R² = 0.10, p = 0.04). Furthermore, this impact of IR on striatal activation was a significant mediator of the faster go speeds and greater impulsivity observed with greater IR. These findings suggest a neural mechanism by which IR may increase impulsivity and degrade behavioral self-regulation.

Overlapping Neural Endophenotypes in Addiction and Obesity

Impulsivity refers to a tendency to act rapidly without full consideration of consequences. The trait is thought to result from the interaction between high arousal responses to potential rewards and poor self-control. Studies have suggested that impulsivity confers vulnerability to both addiction and obesity. However, results in this area are unclear, perhaps due to the high phenotypic complexity of addictions and obesity. Focusing on impulsivity, the aim of this review is to tackle the putative overlaps between addiction and obesity in four domains: (1) personality research, (2) neurocognitive tasks, (3) brain imaging, and (4) clinical evidence. We suggest that three impulsivity-related domains are particularly relevant for our understanding of similarities between addiction and obesity: lower self-control (high Disinhibition/low Conscientiousness), reward sensitivity (high Extraversion/Positive Emotionality), and negative affect (high Neuroticism/Negative Emotionality). Neurocognitive studies have shown that obesity and addiction are both associated with increased impulsive decision-making and attention bias in response to drug or food cues, respectively. Mirroring this, obesity and different forms of addiction seem to exhibit similar alterations in functional MRI brain activity in response to reward processing and during self-control tasks. Overall, our review provides an integrative approach to understand those facets of obesity that present similarities to addictive behaviors. In addition, we suggest that therapeutic interventions targeting inhibitory control may represent a promising approach for the prevention and/or treatment of obesity.