Inhibitory control in obesity and binge eating disorder: A systematic review and meta-analysis of neurocognitive and neuroimaging studies

Inhibitory control is related to fecal short-chain fatty acid concentrations in adults with overweight and obesity

Obesity is a pro-inflammatory condition with negative effects on executive functioning. Increased inflammation dysregulates gastrointestinal homeostasis and alters microbiota community composition. The gut microbiota produce immunomodulatory short-chain fatty acids (SCFA) that have been related to cognition in obesity, but the neural effects are not explored. Here, we hypothesized that greater fecal SCFA would be positively related to neuroelectric markers of inhibitory control and conflict monitoring in obesity. A cross-sectional cohort of 87 adults (35 ± 6 years, 53 females) with overweight and obesity (BMI = 32 ± 6 kg/m2) provided fresh fecal samples and participated in cognitive testing to assess response inhibition and conflict monitoring with electroencephalographic recording. Linear regressions, controlling for age, sex, BMI, and energy-adjusted dietary fiber intake, revealed positive relationships between NoGo N2 mean amplitude and fecal SCFA concentrations. Linear discriminant analysis effect size (LEfSe) revealed 16 amplicon sequence variants differentially abundant between high and low butyrate groups with Roseburia and Adlercreutzia individually related to NoGo N2 mean amplitude in MaAsLin2 modeling. Thus, greater fecal SCFA concentrations and SCFA producing microbiota (i.e., Roseburia) were related to markers of superior conflict monitoring in the NoGo task when adjusting for key covariates. These data highlight key associations between bacterial derived gut signaling molecules and neural regulation in cognitive domains particularly relevant to weight status that warrant further investigation.

Noshing on Chocolate, I Can Do That: Increased Chocolate Consumption in the Chocolate-Modified Bogus Taste Test With Better and Not Worse Inhibitory Control

BACKGROUND

Chocolate is the most craved energy-dense food. Yet, most individuals can limit their chocolate consumption. Here, we investigate the cognitive mechanisms underlying chocolate consumption in a chocolate bogus taste test in a cross-sectional experimental design.

METHOD

High chocolate cravers abstained from chocolate for a week, followed by a virtual reality chocolate exposure with biometric trajectory recordings of their stopping responses and an ad-libitum bogus taste test of spontaneous chocolate intake. A single-target implicit association task and a computerised stop-signal task served as unstandardised control tasks 1-2 days before chocolate intake.

RESULTS

Associations of parameters from all tasks with chocolate intake were small (|r| < 0.23). Elastic net models misestimated food intake by min. 160 kcal (generalisation: 180 kcal) and feature selection was only possible with L1 penalty. At the group level, participants showed a more controlled and delayed movement towards chocolate relative to neutral cues, evidenced by lower peak acceleration and peak velocity and faster stopping latency.

DISCUSSION

The findings demonstrate the complex cognitive-behavioural underpinnings of food intake, food craving and abstinence.

Repetitive transcranial magnetic stimulation of the left dorsolateral prefrontal cortex in binge eating disorder: a double-blind randomized controlled trial

BACKGROUND

Binge-eating disorder (BED) is characterized by highly distressing episodes of loss-of-control over-eating. We have examined the use of repetitive transcranial magnetic stimulation (rTMS) for the treatment of people with BED and associated obesity. Such non-invasive brain stimulation (NIBS) techniques are used therapeutically in several psychiatric conditions and there is an associated scientific rationale.

METHODS

Sixty participants were randomly allocated to receive 20 sessions of neuronavigated 10 Hz rTMS administered to the left dorsolateral prefrontal cortex (dlPFC) or sham treatment. Primary outcomes were the frequency of binge eating episodes (BEE) and the 'urge to eat' (craving) evaluated at baseline and end-of-treatment (8 weeks post-randomization). Secondary outcomes included body mass index (BMI), hunger, general and specific eating disorder psychopathology. Follow-up analyses were conducted for most outcomes at 16 weeks post-randomization. Multilevel models were used to evaluate group, time, and group-by-time interactions for the association between rTMS exposure and outcomes.

RESULTS

The real rTMS group (compared with sham treatment), showed a significantly greater decrease in the number of BEE at the end of treatment (Estimated Mean [EM]: 2.41 95% CI: 1.84-3.15 versus EM: 1.45 95% CI: 1.05-1.99, p = 0.02), and at follow-up (EM: 3.79 95% CI: 3-4.78 versus EM: 2.45 95% CI: 1.88-3.17, p = 0.02; group × time interaction analysis p = 0.02). No group differences were found for other comparisons.

CONCLUSION

rTMS was associated with reduced BEE during and after treatment: it suggests rTMS is a promising intervention for BED.

Neural and Behavioral Correlates of Binge Eating in 9- to 10-Year-Old Children

OBJECTIVE

This observational study compared children with and without binge eating (BE) on biobehavioral measures of reward responsiveness, inhibitory control, and emotion processes, while accounting for the impact of weight.

METHOD

Children aged 9 to 10 years completed the baseline wave of the Adolescent Brain Cognitive Development Study (316 with BE; 7,681 without BE [no-BE]). The prevalence of binge-eating disorder in the BE group was 17.0%; clinically significant internalizing and externalizing symptoms were endorsed by 8.5% and 4.5% of the sample, respectively. The monetary incentive delay (MID) task, stop signal task (SST), and emotional N-Back (EN-Back) task were administered during neuroimaging. Analyses assessed effects of group (BE vs no-BE) on task performance and corresponding neural signal in regions of interest (ROIs). Weight status was evaluated as a covariate and as a moderator of effects.

RESULTS

Adjusting for weight status, the BE group (vs no-BE) group showed lower activation during anticipation of reward, specifically large reward (vs no reward), in the composite ROI consisting of the dorsal striatum, nucleus accumbens, orbital frontal gyrus, amygdala, and insula. Groups did not differ significantly in other behavioral or neural outcomes. No interactions between group and weight status were observed.

CONCLUSION

Blunted anticipatory responses to monetary reward were associated with binge eating during peri-adolescence and may play a role in binge eating pathophysiology. Results challenge prior findings in BE that may be confounded by weight, and highlight the importance of future prospective research across binge-eating disorder stage of illness.

PLAIN LANGUAGE SUMMARY

Binge eating disorder, the most common eating disorder, is associated with several negative psychosocial consequences. This study used data from the Adolescent Brain Cognitive Development (ABCD) Study and compared children (ages 9-10) with and without binge eating on neurobiological and behavioral measures of reward responsiveness, inhibitory control, and emotion processes. Children with binge eating showed lower neural activation during anticipation of reward, specifically large reward, compared to youth without binge eating. These findings suggest that blunted anticipatory response during peri-adolescence may play a role in binge eating pathophysiology.

Examining Food-Specific and General Inhibitory Control and Working Memory as Moderators of Relations Between Emotion Regulation Difficulties and Eating Pathology in Adults With Overweight/Obesity: A Preregistered, Cross-Sectional Study

OBJECTIVE

Empirical research and theory support the interaction of executive functions (e.g., inhibitory control, working memory) and emotion regulation in guiding goal-oriented behavior; however, applications to eating pathology (e.g., binge eating) are limited. Such research is scant with adults with overweight/obesity (AwO/O), a population reporting high levels of binge eating, emotion regulation difficulties, and deficits in inhibitory control and working memory. We tested interactions between emotion regulation and executive functioning in relation to eating pathology in AwO/O while considering stimuli-specific deficits (e.g., food-specific deficits) in behavioral task performance.

METHOD

AwO/O (N = 204; MBMI = 32.11; Mage = 38.30 [SD = 12.16]) completed a preregistered, online study assessing demographics and emotion regulation difficulties (Difficulties in Emotional Regulation Scale), inhibitory control (go/no-go task, food and general stimuli), working memory (N-Back Task, food and general stimuli), binge eating (Binge Eating Scale), and disordered eating (Eating Disorder Examination-Questionnaire).

RESULTS

There was limited evidence of moderation in models examining food-specific and general inhibitory control and working memory, emotion regulation difficulties, and binge eating. Preliminary support was found for emotion regulation difficulties to be more strongly associated with more disordered eating in AwO/O reporting more food-specific and general working memory deficits. Consistent, positive associations between emotion regulation difficulties and eating pathology were observed.

CONCLUSIONS

Among adults with AwO/O, emotion regulation difficulties are closely related to eating pathology, regardless of performance on working memory and inhibitory control tasks. Clinicians and researchers working with AwO/O may consider how emotion regulation difficulties and working memory deficits work together to influence disordered eating.

The Impact of Acute Aerobic Exercise on General and Food-Related Inhibitory Function Among Young Adults with Obesity: An Event-Related Potential (ERP) Study

Backgrounds and Objectives: Obesity presents a significant global public health challenge and is associated with declines in both general and food-related inhibitory control, crucial for maintaining a healthy weight and preventing obesity progression. An increasing body of research suggests that acute aerobic exercise may improve inhibitory function. However, the effects and underlying mechanisms of acute aerobic exercise on both general and food-related inhibition in obese adults remain unclear. This study aimed to explore the potential impacts and underlying neuroelectronic mechanisms of a single session of aerobic exercise at varying intensities on general and food-related inhibitory functions among young adult males with obesity. Design: A within-subject design comprising three sessions (control, low-intensity exercise, moderate-intensity exercise) × three picture types (high-calorie food, low-calorie food, neutral picture) was employed. Methods: Eighteen young adult males with obesity [body mass index (BMI): 34.60 ± 4.21 kg/m2, aged 24.50 ± 5.13 years (Mean ± SD)] were recruited. They participated in three intervention sessions: acute aerobic exercise at low [40-50% maximal Heart Rate (HRmax)], moderate (65-70% HRmax), and a control session (sitting rest), separated by five-day intervals in a counterbalanced order. Following each session, participants performed a food-related Go/No-go task, and EEG recordings (N2 and P3 components) were conducted within 15 min. Results: Moderate-intensity exercise elicited larger N2 amplitudes compared to the control session across different picture types and task conditions. However, there was no significant effect on behavioral indicators or P3 amplitude across sessions. Additionally, food stimuli (both high- and low-calorie) resulted in lower No-go accuracy and smaller N2 amplitudes compared to neutral stimuli. Conclusions: Acute moderate-intensity exercise might influence general and food-related inhibitory function in obese individuals at the neuroelectric stage, potentially by enhancing attentional resources for managing cognitive control and conflict detection. Moreover, reduced N2 amplitudes and No-go accuracy in response to food stimuli compared to non-food stimuli indicate a diminished ability to allocate attentional and neural resources to manage food-related conflicts. However, due to the relatively small sample size, caution is advised when generalizing these findings to the broader population. The pilot test indicated that obese participants had difficulty sustaining high-intensity exercise at 80-90% of their maximum heart rate for a continuous or 20 min period, highlighting potential challenges in exercise adherence at high intensities within this population. Future research is needed to utilize interdisciplinary approaches and multimodal technologies to clarify how exercise influences food-related cognition, appetite regulation, and brain mechanisms in obesity, aiming to better contribute to the prevention and treatment of obesity.

Executive functioning and treatment outcome among adolescents undergoing cognitive-behavioral therapy for binge-eating disorder

BACKGROUND

Cognitive-behavioral therapy (CBT) is an evidence-supported treatment for adolescents with binge-eating disorder (BED). Executive dysfunctions, which are associated with binge eating and elevated body weight in youth, may undermine CBT outcomes by making it difficult for youth to engage with or adhere to treatment, including recalling and/or implementing intervention strategies in real-world contexts.

METHODS

We assessed 73 adolescents [82.2% female; Mage = 15.0 ± 2.5 year; M baseline standardized body mass index (zBMI) = 1.9 ± 1.0 kg/m2] with BED at baseline, posttreatment, 6-, 12-, and 24-month follow-up. Linear mixed models examined the effects of baseline executive functioning (EF) on loss of control (LOC) eating and weight change following CBT. Linear and logistic regressions probed associations between EF, attendance, and attrition.

RESULTS

More impulsive decision-making, as reflected in higher baseline scores on the Iowa Gambling Task, predicted better attendance (β = .07; p = .019) and more frequent LOC eating following treatment (β = .12; p = .017). Lower cognitive flexibility, as reflected in lower baseline T-scores on the Comprehensive Trail Making Test complex sequencing index, predicted higher zBMI following treatment (β = -.03; p = .003). Inhibition, concentration, attention, and parent-reported EF behavior symptoms were not associated with outcome, attendance, or attrition.

CONCLUSIONS

More impulsive decision-making and lower cognitive flexibility were associated with suboptimal response to CBT for BED, although findings should be interpreted with caution in light of the sample size and waitlist control design. Future research should examine whether strengthening EF could improve eating and weight outcomes among adolescents with BED who have lower pre-treatment EF.

Impact of behavioral inhibitory control and startle reactivity to uncertain threat on youth suicide risk

Poor inhibitory control and exaggerated threat reactivity are two well-established risk factors for suicide. Theory suggests that these two factors may interact to influence suicide risk, although few studies have directly tested these relationships. In the present study, we examined the unique and interactive effects of inhibitory control (IC) and threat reactivity on self-reported suicide risk in a sample of 132 youth, ages 16-19. The stop signal task was used as a behavioral index of IC. Threat reactivity was captured using a modified version of the No-Predictable-Unpredictable threat paradigm that includes threat of predictable (P-) and unpredictable (U-) mild electrical shock. Startle eyeblink potentiation was measured throughout the task as an index of aversive responding. All participants completed a battery of well-validated self-report measures including current suicide risk. Hierarchical linear regression analyses controlling for age and sex revealed no main effects of IC or threat reactivity. However, there was a significant IC by reactivity to uncertain threat (U-threat) interaction. At lower levels of IC, greater startle reactivity to U-threat was associated with greater suicide risk. At higher levels of IC, there was no association between reactivity to U-threat and suicide risk. These results suggest that individual differences in IC and reactivity to U-threat interact to influence suicide cognitions, shedding light on potential subgroups of individuals who might be at elevated risk.

Working Memory and Inhibition as Mediators in the Relationship Between Adverse Childhood Experiences and Emotional Eating

Objective: Previous studies have focused on the dual relationship among adverse childhood experiences (ACEs), cognitive abilities, and emotional eating. The current study aims to test the mediating role of executive functioning (working memory and inhibition) between ACEs and emotional eating. Methods: A total of 1105 community-based participants, aged 18-45 (Mean = 26.28, SD = 7.09), were included in the study. Among the participants, 698 (63.16%) were female, and 407 (36.84%) were male. Participants completed the Childhood Trauma Questionnaire; the Adult Executive Functioning Inventory; the Dutch Eating Behaviour Scale; the Life Events Checklist; and the Depression, Anxiety, Stress Scale Short Form. Multiple mediation analyses were employed using MPlus 8.3. Results: Multiple mediation analysis results showed that working memory and inhibition mediate the relationship between ACEs and emotional eating. Furthermore, working memory and inhibition were positively correlated with emotional eating. Discussion: Our findings indicate that difficulties in working memory and inhibition may increase the risk of emotional eating. Early intervention targeting executive functions may prevent emotional eating. Public Significance: Our findings highlight the relationship among ACEs, executive functioning, and emotional eating. Intervening in executive function may have clinical benefits for individuals with ACEs.

A Narrative Review on the Neurocognitive Profiles in Eating Disorders and Higher Weight Individuals: Insights for Targeted Interventions

Background/Objectives: Recent research has increasingly explored the cognitive processes underlying eating disorders (EDs), including anorexia nervosa (AN), bulimia nervosa (BN), binge eating disorder (BED), other specified feeding or eating disorders (OSFEDs), and individuals with higher weight (HW). This critical narrative review focuses on neurocognitive findings derived from mainly experimental tasks to provide a detailed understanding of cognitive functioning across these groups. Where experimental data are lacking, we draw on self-report measures and neuroimaging findings to offer supplementary insights. Method: A search of major databases that prioritized meta-analyses and recent publications (last 10 years) was conducted. Using comprehensive search terms related to EDs, HW, and neurocognition, eligible studies focused on human neurocognitive outcomes (e.g., cognitive flexibility, attentional bias, etc.) published in English were selected. Results: We found that some neurocognitive characteristics, such as cognitive rigidity, impulsivity, emotion processing difficulties, and dysregulated reward processing, appear transdiagnostic, spanning multiple ED subtypes and HW populations. We also revealed neurocognitive features specific to ED subtypes and HW. For instance, individuals with AN demonstrate an enhanced focus on detail, and BN and BED are characterized by a pronounced attentional bias toward food-related stimuli. In individuals with HW, cognitive processes underpin behaviours associated with overeating and weight gain. Conclusions: These findings highlight the critical importance of understanding both the unique and shared neurocognitive patterns across ED subtypes and HW populations. By identifying transdiagnostic factors, such as cognitive rigidity and reward processing, alongside ED subtype/HW-specific vulnerabilities, researchers and clinicians can develop more nuanced, evidence-based interventions that address the core mechanisms driving disordered eating behaviours.

The Impact of Dexamphetamine Treatment for Obesity on Executive Function: A Double-Blind Randomised Controlled Pilot Study

BACKGROUND

Amphetamines increase dopamine levels in mid-brain regions which, in turn, impact top-down executive function. Repeated exposure is linked to substance use disorders. Nonetheless, amphetamines are used to manage attention-deficit/hyperactivity disorder (ADHD) and eating-related disorders. In ADHD, amphetamines upregulate a system characterised by low dopaminergic tone, assisting to improve executive function. A similar process might be at play with eating disorders; however, the effect of amphetamine treatment on executive function in this case has not been thoroughly considered.

METHODS

Participants (N = 52, Mage = 47.06, SD = 12.29) with a body mass index of 25-60 were randomised to treatment (6-week dexamphetamine titration) or control (placebo) groups. They completed an executive function measure-Barkley Deficits in Executive Functioning Scale (BDEFS-SF)-and response inhibition task-Stop-Signal Task (SST)-at Baseline, throughout titration, at Maintenance, and at Follow-up. Mixed effects models examined whether BDEFS-SF score or the SST variable, stop-signal reaction time (SSRT), changed across sessions as a function of treatment.

RESULTS

There was no effect of group (p = 0.440), but an effect of session (p = 0.024) on BDEFS-SF, with scores at Time 2 (p = 0.011, 95% CI [0.47, 3.49]) and Maintenance (p = 0.022, 95% CI [-4.89, -0.39]), respectively, higher and lower than other timepoints. There was no group by session interaction (p = 0.659). R2 (conditional) = 0.74; ICC = 0.73. There was an effect of group (p = 0.039) and session (p < 0.001) on SSRT, but no interaction (p = 0.707). Baseline SSRT was significantly longer than the mean of all subsequent timepoints (p < 0.001, 95% CI [16.29, 33.84]). R2 (conditional) = 0.47; ICC = 0.39.

CONCLUSIONS

There was no discernible impact of amphetamine treatment for obesity on executive function. Our results suggest some variation related to sample size and/or practice effects. Thus, while treatment appears unlikely to render individuals susceptible to substance use disorders, parallels with ADHD might be overstated.

Disentangling inhibition toward food and non-food stimuli across two hunger levels: An fNIRS study

While individuals tend to display poorer inhibitory control toward food-related than neutral stimuli, it is unclear whether this challenge is specific to food or extends to other pleasant stimuli. Uncertainty also remains regarding the general impact of hunger on inhibition. To address these questions, we used a within-subjects design whereby 44 healthy adults completed two go/no-go tasks including no-go images of highly palatable foods and no-go images of animals matched for valence and physical properties. Both tasks were completed one week apart in either a fed or a fasted state. Prefrontal cortex activity was measured using functional near-infrared spectroscopy. Poorer behavioral inhibition was observed when participants needed to withhold their response to images of food compared to animals, regardless of hunger state. In addition, more commission errors were made in the fasted compared to the fed condition, regardless of the type of image to avoid responding to. Responses to go trials were slower when these trials were interspersed with food compared to animal no-go trials. However, hunger did not influence go response time. Greater activation was observed in the dorsolateral prefrontal cortex during blocks of trials with (vs. without) no-go images, but brain activity did not differ according to the type of no-go image. The effect of hunger on prefrontal brain activity was also not significant. Exploratory correlations showed that food-related inhibition deficits were positively related to self-reported impulsivity, but unrelated to body mass index. This study suggests that even among healthy adults, food-related inhibitory control may have a unique behavioral signature beyond general inhibition toward pleasant stimuli. Hunger also exerts an independent influence on general inhibitory capabilities, highlighting the importance of carefully controlling hunger levels in inhibition studies.

Reward and Inhibitory Control as Mechanisms and Treatment Targets for Binge Eating Disorder

PURPOSE OF REVIEW

Recent research has highlighted alterations in reward and inhibitory control among individuals with binge eating disorder, identifying both constructs as potential targets for treatment. Treatments targeting reward and inhibitory control for binge eating disorder are emerging. This review aims to summarize the recent literature evaluating reward and inhibitory control in binge eating disorder compared to weight-matched controls using behavioral paradigms and neuroimaging. This review also aims to summarize recent literature evaluating treatments for binge eating targeting these mechanisms and highlights additional work needed in these areas.

RECENT FINDINGS

Reward hypersensitivity and impaired inhibitory control are mechanisms underlying binge eating disorder. Individuals with binge eating disorder experience higher initial reward to food, and later, higher anticipatory reward but lower experienced food reward which maintains binge eating behavior. Treatments targeting reward and inhibitory control for binge eating include behavioral, computerized trainings, pharmacological, and neuromodulation treatments. The majority of trials are small but demonstrate promise in reducing binge eating and targeting theorized mechanisms. Larger, randomized trials are needed. Changes in reward and inhibitory control are present in individuals with binge eating disorder and treatments targeting these mechanisms demonstrate initial promise. Greater research is needed evaluating reward and inhibitory control simultaneously and with weight-matched comparison groups, as well as larger randomized trials that target both processes simultaneously.

Sex differences in the association of overweight with cognitive performance in individuals with first-episode psychosis

Cognitive deficits and overweight are prominent challenges in the treatment of psychosis, which have a direct impact on patients' quality of life. We aim to determine whether there is an association of overweight with cognitive performance and whether there are sex differences in this association. We included 170 individuals with first-episode psychosis (FEP) (mean age 23.08 years, 32.9% females) attending an early intervention service who underwent clinical, biometric, and cognitive assessments by the MATRICS Consensus Cognitive Battery. A set of two-way analyses of covariance (ANCOVAs) were conducted for each cognitive test. Sex, overweight, and their interaction were included as factors. Nearly 34% of the participants were overweight without differences between males and females. The excess of weight did not exert any main effect on cognition; however, overweight females performed significantly worse than non-overweight females in processing speed, verbal learning and memory, reasoning and problem-solving, and global cognitive function, whereas in males, there were no differences. Our findings highlight that sex matters in the study of metabolic and cognitive factors in FEP to develop targeted interventions based on sex perspectives.

Additive effects of depression and obesity on neural correlates of inhibitory control

BACKGROUND

Depression and obesity are associated with impaired inhibitory control. Behavioral evidence indicates an exacerbating additive effect when both conditions co-occur. However, the underlying neural mechanisms remain unclear. Moreover, systemic inflammation affects neurocognitive performance in both individuals with depression and obesity. Here, we investigate additive effects of depression and obesity on neural correlates of inhibitory control, and examine inflammation as a connecting pathway.

METHODS

We assessed inhibitory control processing in 64 individuals with obesity and varying degrees of depressed mood by probing neural activation and connectivity during an fMRI Stroop task. Additionally, we explored associations of altered neural responses with individual differences in systemic inflammation. Data were collected as part of the BARICO (Bariatric surgery Rijnstate and Radboudumc neuroimaging and Cognition in Obesity) study.

RESULTS

Concurrent depression and obesity were linked to increased functional connectivity between the supplementary motor area and precuneus and between the inferior occipital and inferior parietal gyrus. Exploratory analysis revealed that circulating inflammation markers, including plasma leptin, IL-6, IL-8, and CCL-3 correlated with the additive effect of depression and obesity on altered functional connectivity.

LIMITATIONS

The observational design limits causal inferences. Future research employing longitudinal or intervention designs is required to validate these findings and elucidate causal pathways.

CONCLUSION

These findings suggest increased neural crosstalk underlying impaired inhibitory control in individuals with concurrent obesity and depressed mood. Our results support a model of an additive detrimental effect of concurrent depression and obesity on neurocognitive functioning, with a possible role of inflammation.

Unveiling the neural mechanisms of acute aerobic exercise on inhibitory control among young adults with obesity: Insights from an ERP study

Obesity has become a prominent public health concern worldwide and is associated with adverse cognitive function. Exercise, particularly aerobic exercise, is known to benefit for weight loss and cognitive function. However, whether acute aerobic exercise could yield benefits to obese individuals and the precise brain mechanisms of action remain poorly understood. The study aimed to investigate whether acute aerobic exercise could improve inhibitory control among obese individuals and what neuroelectric mechanisms are implicated. A 3 (session: control, low-intensity exercise, moderate-intensity exercise) × 2 (congruency: congruent, incongruent) within-subject design was conducted. 18 obese young male adults underwent three sessions of 30-min interventions in a counterbalanced order seperated by five days: moderate-intensity aerobic exercise (MIE), low-intensity aerobic exercise (LIE) and a control session (a sedentary period of seated rest). The Flanker task and EEG recordings (N2 and P3 amplitude) were investigated following exercise and the control treatment. Results showed that the N2 amplitude following MIE was larger than the control session, whereas a larger N2 and reduced congruent P3 amplitude was observed following MIE than LIE. However, no main effect of the session was found for reaction time and accuracy, but a significant main effect of congruency was observed. These findings suggest acute moderate-intensity aerobic exercise may modulate brain activity through enhanced recruitment of attentional resources for cognitive control and conflict monitoring in adults with obesity.

The impact of exercise on food-related inhibitory control- do calories, time of day, and BMI matter? Evidence from an event-related potential (ERP) study

A growing body of research suggests exercise improves inhibitory control functions. We tested if exercise-related inhibitory control benefits extend to food-related inhibitory control and differ by calorie content, time of day, and weight status. One hundred thirty-eight individuals were pseudo-randomly assigned to a morning or evening group. Each subject participated in two lab sessions where they completed questionnaires (rest session) or walked on a treadmill at 3.8mph (exercise session) for 45 min. After each session, participants completed both a high-calorie and low-calorie go/no-go task while N2 and P3 event-related potentials (ERP), both neural indicators of inhibitory control, were measured. Participants also rated food images for valence and arousal. While N2 and P3 difference amplitudes were larger to high-calorie than low-calorie foods, neither exercise nor time of day affected results. Individuals had faster response times after exercise without decreases in accuracy. Arousal and valence for high-calorie foods were lower after exercise and lower for all foods after morning compared to evening exercise. In a subset of individuals with obesity and normal-weight individuals, individuals with obesity had larger N2 difference amplitudes after morning exercise, while normal-weight individuals had larger P3 difference amplitudes to high-calorie foods after exercise. Results suggest moderate exercise did not affect food-related inhibitory control generally, although morning exercise may be beneficial in improving early recruitment of food-related inhibitory control in individuals with obesity. Moderate exercise, particularly in the morning, may also help manage increased attention allocated to food.

Functional alterations in overweight/obesity: focusing on the reward and executive control network

Overweight (OW) and obesity (OB) have become prevalent issues in the global public health arena. Serving as a prominent risk factor for various chronic diseases, overweight/obesity not only poses serious threats to people's physical and mental health but also imposes significant medical and economic burdens on society as a whole. In recent years, there has been a growing focus on basic scientific research dedicated to seeking the neural evidence underlying overweight/obesity, aiming to elucidate its causes and effects by revealing functional alterations in brain networks. Among them, dysfunction in the reward network (RN) and executive control network (ECN) during both resting state and task conditions is considered pivotal in neuroscience research on overweight/obesity. Their aberrations contribute to explaining why persons with overweight/obesity exhibit heightened sensitivity to food rewards and eating disinhibition. This review centers on the reward and executive control network by analyzing and organizing the resting-state and task-based fMRI studies of functional brain network alterations in overweight/obesity. Building upon this foundation, the authors further summarize a reward-inhibition dual-system model, with a view to establishing a theoretical framework for future exploration in this field.

Mechanisms underlying food devaluation after response inhibition to food

Multiple studies reveal that a requirement to stop a response to appetitive food stimuli causes devaluation of these stimuli. However, the mechanism underlying food devaluation after stopping is still under debate. The immediate-affect theory suggests that an increase in negative affect after stopping a response is the driving force for food devaluation. A competing value-updating theory presumes that food devaluation after stopping occurs through the need to align behavior with goals. The current study assessed how food devaluation after response inhibition is influenced by negative emotional reactivity and behavior-goal alignment on a trial-by-trial basis. The study included 60 healthy participants who completed a Food-Stop-Signal-Emotion task. Participants categorized high vs. low-calorie food stimuli and stopped their response upon encountering a stop signal. Subsequently, participants made subjective negativity ratings of negative- or neutral-valenced emotional images, and rated their desire to eat the previously depicted food. In contrast to predictions made by the immediate-affect account, food devaluation after stopping was not mediated nor moderated via changes in negative emotional reactivity after stopping. In support of the value-updating account, food devaluation was modulated by behavior-goal alignment, indicated by larger food devaluation after successful vs. failed stopping. In agreement with this theory, the findings indicate that devaluation occurs more strongly when performance aligns with the task requirement. This study sheds light on the mechanism that likely underlies food devaluation after stopping. Implications regarding applied use of food-inhibition trainings are discussed.

Food-related inhibitory control deficits in young male adults with obesity: Behavioral and ERP evidence from a food-related go/no-go task

PURPOSE

Obesity poses a pervasive challenge to global public health, which is linked to adverse physical health outcomes and cognitive decline. Cognitive function, particularly food-related cognitive function, plays a critical role in sustaining a healthy weight and mitigating the progression of obesity. The aim of this study was to investigate the behavioral and neuroelectronic aspects of food-related inhibitory functions in young adult males with obesity.

METHODS

Forty-nine participants with obesity and healthy-weight were recruited (BMI = 35.83 ± 5.06 kg/m2 vs. 22.55 ± 1.73 kg/m2, age = 24.23 ± 4.55 years vs. 26.00 ± 3.97 years). A food-related Go/No-go task which included 6 distinct blocks in a randomized order was conducted to investigate the general and food-related inhibitory control. 180 stimulus images from the Food Picture Database encompassing high-calorie food, low-calorie food, and neutral images were selected. Behavioral (Go RT, Go ACC, No-go ACC) and event-related potential measures (N2 and P3 amplitude) during the food-related Go/No-go task were measured.

RESULTS

The main findings indicated that the group with obesity exhibited lower No-go accuracy, slower go reaction times, and smaller P3 amplitudes in high-calorie, low-calorie foods, and neutral picture, compared to the normal-weight group, but with no group difference in N2. Additionally, high-calorie food induced larger N2 and P3 amplitude than the neutral stimuli.

CONCLUSIONS

Young male adults with obesity exhibit poorer inhibitory control in both food and non-food domains, specifically in slower reaction time and reduced accuracy, featuring difficulties in neural resource recruitment during the inhibitory control process. Additionally, the P3 component could serve as sensitive indicators to reveal the neural mechanisms of inhibitory control deficits in obesity, while the N2 and P3 components may differentiate the neural differences between high-calorie foods and non-foods in inhibitory control processing. Food, especially high-calorie food, induces more neural resources and may exacerbate the poor inhibitory ability towards food in obesity. Targeted interventions such as exercise interventions, cognitive training as well as neuromodulation interventions are warranted in the future to improve impaired general and food-related inhibitory functions in the obese populations, offering both theoretical and practical frameworks for obesity prevention and treatment.

Network-targeted transcranial direct current stimulation of the hypothalamus appetite-control network: a feasibility study

The hypothalamus is the key regulator for energy homeostasis and is functionally connected to striatal and cortical regions vital for the inhibitory control of appetite. Hence, the ability to non-invasively modulate the hypothalamus network could open new ways for the treatment of metabolic diseases. Here, we tested a novel method for network-targeted transcranial direct current stimulation (net-tDCS) to influence the excitability of brain regions involved in the control of appetite. Based on the resting-state functional connectivity map of the hypothalamus, a 12-channel net-tDCS protocol was generated (Neuroelectrics Starstim system), which included anodal, cathodal and sham stimulation. Ten participants with overweight or obesity were enrolled in a sham-controlled, crossover study. During stimulation or sham control, participants completed a stop-signal task to measure inhibitory control. Overall, stimulation was well tolerated. Anodal net-tDCS resulted in faster stop signal reaction time (SSRT) compared to sham (p = 0.039) and cathodal net-tDCS (p = 0.042). Baseline functional connectivity of the target network correlated with SSRT after anodal compared to sham stimulation (p = 0.016). These preliminary data indicate that modulating hypothalamus functional network connectivity via net-tDCS may result in improved inhibitory control. Further studies need to evaluate the effects on eating behavior and metabolism.

Eating disorders and obesity: bridging clinical, neurobiological, and therapeutic perspectives

Eating disorders (EDs) and obesity are complex health conditions sharing various risk and maintenance factors, intensified in cases of comorbidity. This review explores the similarities and connections between these conditions, examining different facets from a multidisciplinary perspective, among them comorbidities, metabolic and psychological factors, neurobiological aspects, and management and therapy implications. We aim to investigate the common characteristics and complexities of weight and EDs and explore their interrelationships in individuals who experience both. The rising prevalence of EDs in people with obesity necessitates integrated approaches to study this comorbidity and to identify and analyze both common and distinct features of these conditions. This review may offer new opportunities for simultaneous prevention and management approaches, as well as future lines of research.

The effectiveness of Go/No-Go and Stop-Signal training in reducing food consumption and choice: A systematic review and meta-analysis

The Go/No-Go and Stop-Signal tasks have been used to reduce excess food intake via repeated pairing of food cues with response inhibition. A meta analysis of 32 studies was conducted to determine whether, and under which conditions, the Go/No-Go and Stop-Signal training tasks are effective in reducing food consumption or choice. Moderators included task parameters (e.g., number of sessions, stop signal), sample differences (e.g., age, weight), and the measure of food consumption or choice. Overall, there was a small effect for Go/No-Go and Stop-Signal training in reducing food consumption or choice, g = -0.21, CI95 = [-0.31, -0.11], p < .001, with this holding individually only for a single session of the Go/No-Go Task, g = -0.31, CI95 = [-0.45, -0.18], p < .001. Comprehensive investigation of the impact of varying moderators indicated that the effect for Go/No-Go training was robust. Nevertheless, there was significant variation in the specific parameters of the task. Overall, the present meta-analysis extends previous findings by providing comprehensive evidence that the Go/No-Go Task is effective in reducing food consumption and choice, as well as providing optimal parameter recommendations for the task.

Modal and amodal cognition: an overarching principle in various domains of psychology

Accounting for how the human mind represents the internal and external world is a crucial feature of many theories of human cognition. Central to this question is the distinction between modal as opposed to amodal representational formats. It has often been assumed that one but not both of these two types of representations underlie processing in specific domains of cognition (e.g., perception, mental imagery, and language). However, in this paper, we suggest that both formats play a major role in most cognitive domains. We believe that a comprehensive theory of cognition requires a solid understanding of these representational formats and their functional roles within and across different domains of cognition, the developmental trajectory of these representational formats, and their role in dysfunctional behavior. Here we sketch such an overarching perspective that brings together research from diverse subdisciplines of psychology on modal and amodal representational formats so as to unravel their functional principles and their interactions.

Poorer inhibitory control was related to greater food intake across meals varying in portion size: A randomized crossover trial

Individuals eat more food when larger portions are served, and this portion size effect could be influenced by inhibitory control (the ability to suppress an automatic response). Inhibitory control may also relate to obesogenic meal behaviors such as eating faster, taking larger bites, and frequent switching between meal components (such as bites of food and sips of water). In a randomized crossover design, 44 adults ate lunch four times in the laboratory. Lunch consisted of a pasta dish that was varied in portion size (400, 500, 600, or 700 g) along with 700 g of water. Meals were video-recorded to assess meal duration and bite and sip counts, which were used to determine mean eating rate (g/min), mean bite size (g/bite), and number of switches between bites and sips. Participants completed a food-specific stop-signal task, which was used to calculate Stop-Signal Reaction Time (SSRT). Across participants, SSRT values ranged from 143 to 306 msec, where greater SSRT indicates poorer inhibitory control. As expected, serving larger portions increased meal intake (p < 0.0001); compared to the smallest portion, intake of the largest increased by 121 ± 17 g (mean ± SEM). SSRT did not moderate the portion size effect (p = 0.34), but individuals with poorer inhibitory control ate more across all meals: 24 ± 11 g for each one SD unit increase in SSRT (p = 0.035). SSRT was not related to eating rate or bite size (both p > 0.13), but poorer inhibitory control predicted greater switching between bites and sips, such that 1.5 ± 0.7 more switches were made during meals for each one SD unit increase in SSRT (p = 0.03). These findings indicate that inhibitory control can contribute to overconsumption across meals varying in portion size, potentially in part by promoting switching behavior.

Near-infrared spectroscopy and electroencephalography neurofeedback for binge-eating disorder: an exploratory randomized trial

BACKGROUND

Binge-eating disorder (BED) co-occurs with neurobehavioral alterations in the processing of disorder-relevant content such as visual food stimuli. Whether neurofeedback (NF) directly targeting them is suited for treatment remains unclear. This study sought to determine feasibility and estimate effects of individualized, functional near-infrared spectroscopy-based real-time NF (rtfNIRS-NF) and high-beta electroencephalography-based NF (EEG-NF), assuming superiority over waitlist (WL).

METHODS

Single-center, assessor-blinded feasibility study with randomization to rtfNIRS-NF, EEG-NF, or WL and assessments at baseline (t0), postassessment (t1), and 6-month follow-up (t2). NF comprised 12 60-min food-specific rtfNIRS-NF or EEG-NF sessions over 8 weeks. Primary outcome was the binge-eating frequency at t1 assessed interview-based. Secondary outcomes included feasibility, eating disorder symptoms, mental and physical health, weight management-related behavior, executive functions, and brain activity at t1 and t2.

RESULTS

In 72 patients (intent-to-treat), the results showed feasibility of NF regarding recruitment, attrition, adherence, compliance, acceptance, and assessment completion. Binge eating improved at t1 by -8.0 episodes, without superiority of NF v. WL (-0.8 episodes, 95% CI -2.4 to 4.0), but with improved estimates in NF at t2 relative to t1. NF was better than WL for food craving, anxiety symptoms, and body mass index, but overall effects were mostly small. Brain activity changes were near zero.

CONCLUSIONS

The results show feasibility of food-specific rtfNIRS-NF and EEG-NF in BED, and no posttreatment differences v. WL, but possible continued improvement of binge eating. Confirmatory and mechanistic evidence is warranted in a double-blind randomized design with long-term follow-up, considering dose-response relationships and modes of delivery.

Cognitive and motor impulsivity in the healthy brain, and implications for eating disorders and obesity: A coordinate-based meta-analysis and systematic review

Alterations in the impulse-control balance, and in its neural bases, have been reported in obesity and eating disorders (EDs). Neuroimaging studies suggest a role of fronto-parietal networks in impulsive behaviour, with evaluation and anticipatory processes additionally recruiting meso-limbic regions. However, whether distinct facets of cognitive and motor impulsivity involve common vs. specific neural correlates remains unclear. We addressed this issue through Activation Likelihood Estimation (ALE) meta-analyses of fMRI studies on delay discounting (DD) and go/no-go (GNG) tasks, alongside conjunction and subtraction analyses. We also performed systematic reviews of neuroimaging studies using the same tasks in individuals with obesity or EDs. ALE results showed consistent activations in the striatum, anterior/posterior cingulate cortex, medial/left superior frontal gyrus and left supramarginal gyrus for impulsive choices in DD, while GNG tasks elicited mainly right-lateralized fronto-parietal activations. Conjunction and subtraction analyses showed: i) common bilateral responses in the caudate nucleus; ii) DD-specific responses in the ventral striatum, anterior/posterior cingulate cortex, left supramarginal and medial frontal gyri; iii) GNG-specific activations in the right inferior parietal cortex. Altered fronto-lateral responses to both tasks are suggestive of dysfunctional cortico-striatal balance in obesity and EDs, but these findings are controversial due to the limited number of studies directly comparing patients and controls. Overall, we found evidence for distinctive neural correlates of the motor and cognitive facets of impulsivity: the right inferior parietal lobe underpins action inhibition, whereas fronto-striatal regions and the left supramarginal gyrus are related to impulsive decision-making. While showing that further research on clinical samples is required to better characterize the neural bases of their behavioural changes, these findings help refining neurocognitive model of impulsivity and highlight potential translational implications for EDs and obesity treatment.

Executive function differences as a function of parent-reported binge eating and weight: Results from the adolescent brain cognitive development study

Background

Binge eating is a relatively common disordered eating behavior among children, and is associated with poor health outcomes. Executive function (EF)-higher order cognitive abilities related to planning and impulse control-may be implicated in both binge eating and pediatric obesity. Although EF deficits are evident among individuals with obesity and/or binge eating, findings are mixed across the lifespan.

Methods

The present study examined differences in EF among children with varying weight statuses and parent-reported binge eating. The sample included 10,017 children from the Adolescent Brain Cognitive Development study, aged 9-10 years.

Results

Children with parent-reported binge eating-either with overweight/obesity or normal weight-had significantly lower EF than those with no binge eating and a normal weight status but did not differ from those with no binge eating and overweight/obesity. Children with no binge eating and overweight/obesity also had statistically significantly lower EF than those with normal weight status. Although all significant differences between groups were negligible to very small, results may indicate similar neurocognitive profiles among children with binge eating and those with overweight/obesity.

Conclusions

Alterations in EF among children with binge eating may not be solely related to weight-specific factors, as significant differences also emerged among children with normal weight status, with versus without parent-reported binge eating. Future research is needed to understand temporal associations between obesity, disordered eating, and neurocognition in children using multi-informant methods for assessing binge eating.

Obesity surgery and neural correlates of human eating behaviour: A systematic review of functional MRI studies

Changes in eating behaviour including reductions in appetite and food intake, and healthier food cue reactivity, reward, hedonics and potentially also preference, contribute to weight loss and its health benefits after obesity surgery. Functional magnetic resonance imaging (fMRI) has been increasingly used to interrogate the neural correlates of eating behaviour in obesity, including brain reward-cognitive systems, changes after obesity surgery, and links with alterations in the gut-hormone-brain axis. Neural responses to food cues can be measured by changes in blood oxygen level dependent (BOLD) signal in brain regions involved in reward processing, including caudate, putamen, nucleus accumbens, insula, amygdala, orbitofrontal cortex, and top-down inhibitory control, including dorsolateral prefrontal cortex (dlPFC). This systematic review aimed to examine: (i) results of human fMRI studies involving obesity surgery, (ii) important methodological differences in study design across studies, and (iii) correlations and associations of fMRI findings with clinical outcomes, other eating behaviour measures and mechanistic measures. Of 741 articles identified, 23 were eligible for inclusion: 16 (69.6%) longitudinal, two (8.7%) predictive, and five (21.7%) cross-sectional studies. Seventeen studies (77.3%) included patients having Roux-en-Y gastric bypass (RYGB) surgery, six (26.1%) vertical sleeve gastrectomy (VSG), and five (21.7%) laparoscopic adjustable gastric banding (LAGB). The majority of studies (86.0%) were identified as having a very low risk of bias, though only six (27.3%) were controlled interventional studies, with none including randomisation to surgical and control interventions. The remaining studies (14.0%) had a low risk of bias driven by their control groups not having an active treatment. After RYGB surgery, food cue reactivity often decreased or was unchanged in brain reward systems, and there were inconsistent findings as to whether reductions in food cue reactivity was greater for high-energy than low-energy foods. There was minimal evidence from studies of VSG and LAGB surgeries for changes in food cue reactivity in brain reward systems, though effects of VSG surgery on food cue reactivity in the dlPFC were more consistently found. There was consistent evidence for post-operative increases in satiety gut hormones glucagon-like-peptide 1 (GLP-1) and peptide YY (PYY) mediating reduced food cue reactivity after RYGB surgery, including two interventional studies. Methodological heterogeneity across studies, including nutritional state, nature of food cues, post-operative timing, lack of control groups for order effects and weight loss or dietary/psychological advice, and often small sample sizes, limited the conclusions that could be drawn, especially for correlational analyses with clinical outcomes, other eating behaviour measures and potential mediators. This systematic review provides a detailed data resource for those performing or analysing fMRI studies of obesity surgery and makes suggestions to help improve reporting and design of such studies, as well as future directions.

Acute high-intensity interval exercise improves food-related cognition in young adults with obesity: An ERP study

Purpose Cognitive function, particularly food-related cognition, is critical for maintaining a healthy weight and preventing the acceleration of obesity. High-Intensity Interval Exercise (HIIE) is an increasingly popular form of exercise and has been shown to improve physical fitness and cognitive function. However, there is limited research on the effects and underlying mechanisms of HIIE on general and food-related cognition among adults with obesity. The aim of the current study was to examine the influence of a single bout of HIIE on food-related cognition among young adults with obesity. Methods Fifteen young men with obesity (BMI = 33.88 ± 4.22, age = 24.60 ± 5.29 years) were recruited. Participants took part in a HIIE condition consisting of 30 minutes of stationary cycle exercise (5-min warm-up, 20-min HIIE and 5-min cool down), and a control session consisting of a time and attention-matched period of sedentary rest in a counterbalanced order. Behavioral (reaction time and accuracy) and event-related potential measures (P3 and the late positive potential, LPP) elicited during a food-related Flanker task were measured after the HIIE and control session. Results Shorter response times were observed following HIIE, regardless of congruency or picture type, with no change in accuracy. Increased P3 and LPP amplitudes were observed following HIIE relative to the control session. Conclusion The findings suggest a single bout of HIIE has a beneficial effect on general and food-related cognition among young adults with obesity, with increased recruitment of cognitive resources to support cognitive control. Future research is warranted to examine the dose-response relationship between acute bouts or longer participation in HIIE on food-related cognition in obesity.

Dynamical alterations of brain function and gut microbiome in weight loss

OBJECTIVE

Intermittent energy restriction (IER) is an effective weight loss strategy. However, little is known about the dynamic effects of IER on the brain-gut-microbiome axis.

METHODS

In this study, a total of 25 obese individuals successfully lost weight after a 2-month IER intervention. FMRI was used to determine the activity of brain regions. Metagenomic sequencing was performed to identify differentially abundant gut microbes and pathways in from fecal samples.

RESULTS

Our results showed that IER longitudinally reduced the activity of obese-related brain regions at different timepoints, including the inferior frontal orbital gyrus in the cognitive control circuit, the putamen in the emotion and learning circuit, and the anterior cingulate cortex in the sensory circuit. IER longitudinally reduced E. coli abundance across multiple timepoints while elevating the abundance of obesity-related Faecalibacterium prausnitzii, Parabacteroides distasonis, and Bacterokles uniformis. Correlation analysis revealed longitudinally correlations between gut bacteria abundance alterations and brain activity changes.

CONCLUSIONS

There was dynamical alteration of BGM axis (the communication of E. coli with specific brain regions) during the weight loss under the IER.

Mechanisms underlying fNIRS-neurofeedback over the prefrontal cortex for participants with binge-eating disorder

OBJECTIVE

Despite the increasing popularity of neurofeedback (NF), aiming at voluntary modulation of dysfunctional prefrontal cortex (PFC) signals in the treatment of binge-eating disorder (BED) and/or overweight, mechanisms remain poorly understood.

METHODS

Based on a randomized-controlled trial offering 12 food-specific real-time functional near-infrared spectroscopy (rtfNIRS)-NF sessions to participants with BED (n = 22), this preregistered study examined (1) online regulation success as predictor for offline regulation success, defined by PFC signals during regulation versus watch, and subjective regulation success, and (2) changes in loss of control (LOC) eating after vs. before and across 12 rtfNIRS-NF-sessions.

RESULTS

Higher online regulation success expectedly predicted better subjective, but worse offline regulation success. LOC eating decreased after vs. before, but not over rtfNIRS-NF-sessions, and was not associated with subjective or offline regulation success.

CONCLUSIONS

The association between online and subjective regulation success confirmed the presumed mechanism of operant conditioning underlying rtfNIRS-NF-learning. The contrary association between online and offline regulation indicated differential PFC involvement upon subtraction of automatic food-specific responses from regulation signals for offline success. Decreased LOC eating after food-specific rtfNIRS-NF-sessions suggested the potential of NF in BED treatment.

SIGNIFICANCE

Results may guide the optimization of future NF studies in larger samples with BED.

Adding executive function training to cognitive behavioral therapy for binge eating disorder: A pilot randomized controlled trial

Evidence-based treatments for binge eating disorder (BED), such as cognitive behavioral therapy (CBT) lead to successful outcomes only about half the time. Individuals with BED often have measurable deficits in executive function (EF) that may challenge adherence to or impact of cognitive behavioral intervention components. The aim of this study was to evaluate the impact of adding EF training to CBT by combining CBT with a compensatory cognitive training approach (EF-CBT). Participants were 32 adults with BED, overweight/obesity, and comorbid anxiety or depression who were randomly assigned to four months of group treatment in either standard CBT or EF-CBT. Outcomes were assessed at baseline, post-treatment, and at 2-month follow-up. Results showed that EF-CBT was feasible and acceptable, comparable to CBT. Both groups significantly decreased loss of control (LOC) days, clinical impairment, and depression at post-treatment and 2-month follow-up; though there were no differences between groups. Neither group significantly reduced anxiety or weight. Exploratory analyses found that participants with lower EF treated with EF-CBT were less likely to have LOC at post-treatment than those with lower EF treated with CBT. Higher self-monitoring rates during treatment were associated with lower LOC at post-treatment and participants with lower EF were more likely to self-monitor in the EF-CBT arm relative to the CBT arm. These findings suggest that EF-CBT is feasible, acceptable and efficacious, although larger scale research is needed. EF-CBT may be particularly suited for individuals with BED who have lower EF.

Predictors of neurofeedback treatment outcome in binge-eating disorder: An exploratory study

OBJECTIVE

Knowledge on predictors for treatment response to psychotherapy in binge-eating disorder (BED) is mixed and not yet available for increasingly popular neurofeedback (NF) treatment targeting self-regulation of aberrant brain activity. This study examined eating disorder- and psychopathology-related predictors for NF treatment success in BED.

METHOD

Patients with BED (N = 78) were randomized to 12 sessions of real-time functional near-infrared spectroscopy (rtfNIRS)-NF, targeting individual prefrontal cortex signal up-regulation, electroencephalography (EEG)-NF, targeting down-regulation of fronto-central beta activity, or waitlist (WL). The few studies assessing predictors for clinical outcomes after NF and evidenced predictors for psychotherapy guided the selection of baseline eating disorder-related predictors, including objective binge-eating (OBE) frequency, eating disorder psychopathology (EDP), food cravings, and body mass index (BMI), and general psychopathology-related predictors, including depressive and anxiety symptoms, impulsivity, emotion dysregulation, and self-efficacy. These questionnaire-based or objectively assessed (BMI) predictors were regressed on outcomes OBE frequency and EDP as key features of BED at post-treatment (t1) and 6-month follow-up (t2) in preregistered generalized mixed models (https://osf.io/4aktp).

RESULTS

Higher EDP, food cravings, and BMI predicted worse outcomes across all groups at t1 and t2. General psychopathology-related predictors did not predict outcomes at t1 and t2. Explorative analyses indicated that lower OBE frequency and higher self-efficacy predicted lower OBE frequency, and lower EDP predicted lower EDP after the waiting period in WL.

DISCUSSION

Consistent with findings for psychotherapy, higher eating disorder-related predictors were associated with higher EDP and OBE frequency. The specificity of psychopathological predictors for NF treatment success warrants further examination.

PUBLIC SIGNIFICANCE

This exploratory study firstly assessed eating disorder- and psychopathology-related predictors for neurofeedback treatment outcome in binge-eating disorder and overweight. Findings showed an association between higher eating disorder symptoms and worse neurofeedback outcomes, indicating special needs to be considered in neurofeedback treatment for patients with a higher binge-eating disorder symptom burden. In general, outcomes and assignment to neurofeedback treatment may be improved upon consideration of baseline psychological variables.

The use of non-invasive brain stimulation techniques to reduce body weight and food cravings: A systematic review and meta-analysis

Several studies demonstrated non-invasive brain stimulation (NIBS) techniques such as transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS) are safe and simple techniques that can reduce body weight, food cravings, and food consumption in patients with obesity. However, a systematic to evaluate the efficacy of active NIBS versus sham stimulation in reducing body weight and food cravings in patients with obesity is not available. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) using PubMed, Embase, MEDLINE, and Cochrane Central Register of Control Trial between January 1990 and February 2022. Mean differences (MDs) for continuous outcome variables with 95% confidence intervals (95% CIs) were used to examine the effects of NIBS on body weight and body mass index (BMI), whereas the hedges's g test was used to measure the effects on food craving. Nineteen RCTs involving 571 participants were included in this study. Active neurostimulation (TMS and tDCS) was significantly more likely than sham stimulation to reduce body weight (TMS: -3.29 kg, 95% CI [-5.32, -1.26]; I2  = 48%; p < .001; tDCS: -0.82 kg, 95% CI [-1.01, -0.62]; I2  = 0.0%; p = .00) and BMI (TMS: -0.74, 95% CI [-1.17, -0.31]; I2  = 0% p = .00; tDCS: MD = -0.55, 95% CI [-2.32, 1.21]; I2  = 0% p = .54) as well as food cravings (TMS: g = -0.91, 95% CI [-1.68, -0.14]; I2  = 88 p = .00; tDCS: g = -0.32, 95% CI [-0.62, -0.02]; p = .04). Compared with sham stimulation, our findings indicate that active NIBS can significantly help to reduce body weight and food cravings. Hence, these novel techniques may be used as primary or adjunct tools in treating patients with obesity.

Does inhibitory control spill over to eating behaviors? Two preregistered studies of inhibitory spillover effects on food intake and reactions to food stimuli

Overweight and obesity are worldwide conditions associated with detrimental medical and psychosocial outcomes. As inhibitory control deficits are thought to contribute to weight gain, they are a worthwhile target for new approaches. Previous research has shown that the execution of inhibitory control in one domain leads to a concurrent increase of inhibitory control in another domain, an effect denoted as inhibitory spillover effect (ISE). Therefore, we assumed that exertion of inhibitory control in a food-unrelated domain in overweight and normal weight individuals will decrease food intake in a simultaneous bogus taste test (BTT; study 1) as well as increase food-specific response inhibition ability in a stop signal task (SST; study 2). We assumed stronger effects in overweight individuals. In both studies ISE was induced via cognitive priming and compared to a neutral condition in a group of overweight (OW: n = 46 for study 1, n = 46 for study 2) and normal weight (NW: n = 46 for study 1, n = 46 for study 2) individuals. In the ISE condition with an inhibitory control priming task, participants had to learn and retain control-related words while simultaneously performing a BTT (study 1) or SST (study 2). In the neutral condition, participants followed the same protocol, albeit memorizing neutral (i.e., control-unrelated) words. There was no significant interaction of weight group × cognitive priming condition neither regarding food intake (study 1) nor regarding food-related response inhibition (study 2). Cognitive priming, as implemented in the present studies, does not instigate an ISE strong enough to improve inhibitory control during food intake or food-related response inhibition. Relevant practical and theoretical aspects as well as implications for future research on the ISE are discussed.

Food stimuli decrease activation in regions of the prefrontal cortex related to executive function: an fNIRS study

PURPOSE

Overweight/obese individuals show impairments in executive functions such as inhibitory control. However, the neural mechanisms underlying these disturbances-and specifically, whether or not they involve altered activation of the specific prefrontal cortex regions-are not yet fully understood.

METHODS

The motivational dimensional model of affect suggests that high approach-motivated positive affect (e.g., desire) may impair executive function. In the present study, we investigated individual differences in neural responses to videos of food stimuli, and examined brain activity during a cognitive task in an approach-motivated positive state using functional near-infrared spectroscopy (fNIRS). In Experiment 1, in 16 healthy young adults, we tested whether prefrontal cortex activation differed during a food video clip versus a neutral video clip. Then, after viewing each video clip, we tested for differences in executive function performance and prefrontal cortex activation during a Stroop task. Experiment 2 was the same, except that we compared 20 overweight/obese with 20 healthy young adults, and it incorporated only the food video clip.

RESULTS AND CONCLUSIONS

The results of both experiments indicated that food stimuli decrease activation in regions of the prefrontal cortex related to executive function. This study also suggests that overweight/obese might consciously suppress their responses to a desired stimulus, yet here it seems that effect was less pronounced than in healthy controls.

LEVEL OF EVIDENCE

Level II, Cohort Studies.

Effects of bariatric surgery and dietary interventions for obesity on brain neurotransmitter systems and metabolism: A systematic review of positron emission tomography (PET) and single-photon emission computed tomography (SPECT) studies

This systematic review collates studies of dietary or bariatric surgery interventions for obesity using positron emission tomography and single-photon emission computed tomography. Of 604 publications identified, 22 met inclusion criteria. Twelve studies assessed bariatric surgery (seven gastric bypass, five gastric bypass/sleeve gastrectomy), and ten dietary interventions (six low-calorie diet, three very low-calorie diet, one prolonged fasting). Thirteen studies examined neurotransmitter systems (six used tracers for dopamine DRD2/3 receptors: two each for 11 C-raclopride, 18 F-fallypride, 123 I-IBZM; one for dopamine transporter, 123 I-FP-CIT; one used tracer for serotonin 5-HT2A receptor, 18 F-altanserin; two used tracers for serotonin transporter, 11 C-DASB or 123 I-FP-CIT; two used tracer for μ-opioid receptor, 11 C-carfentanil; one used tracer for noradrenaline transporter, 11 C-MRB); seven studies assessed glucose uptake using 18 F-fluorodeoxyglucose; four studies assessed regional cerebral blood flow using 15 O-H2 O (one study also used arterial spin labeling); and two studies measured fatty acid uptake using 18 F-FTHA and one using 11 C-palmitate. The review summarizes findings and correlations with clinical outcomes, eating behavior, and mechanistic mediators. The small number of studies using each tracer and intervention, lack of dietary intervention control groups in any surgical studies, heterogeneity in time since intervention and degree of weight loss, and small sample sizes hindered the drawing of robust conclusions across studies.

Impulsivity and compulsivity in gambling disorder and bulimic spectrum eating disorders: Analysis of neuropsychological profiles and sex differences

BACKGROUND

Gambling disorder (GD) and bulimic spectrum eating disorders (BSDs) not only share numerous psychopathological, neurobiological, and comorbidity features but also are distinguished by the presence of inappropriate behaviours related to impulsivity and compulsivity. This study aimed to emphasise the differences and similarities in the main impulsivity and compulsivity features between GD and BSD patients, and to analyse the potential influence of sex in these domains.

METHODS

Using self-reported and neurocognitive measures, we assessed different impulsive-compulsive components in a sample of 218 female and male patients (59 with BSD and 159 with GD) and 150 healthy controls.

RESULTS

We observed that GD and BSDs exhibited elevated levels of impulsivity and compulsivity in all the dimensions compared to healthy controls. Moreover, these disorders showed differences in several personality traits, such as high novelty seeking in GD, and low persistence and high harm avoidance in BSDs. In addition, patients with BSDs also displayed a trend towards greater impulsive choice than GD patients. Regarding sex effects, GD women presented higher overall impulsivity and compulsivity than GD men. Nevertheless, no sex differences were found in BSDs.

CONCLUSIONS

Clinical interventions should consider these deficits to enhance their effectiveness, including adjunctive treatment to target these difficulties. Our findings also provide support to the relevance of sex in GD, which should also be considered in clinical interventions.

Applying psycho-behavioural phenotyping in obesity characterization

Individual differences in obesity, beyond being explained by metabolic and medical complications, are understood by alterations in eating behaviour which underlie psychological processes. From this psychological perspective, studies have identified several potential characteristic features at the psycho-behavioural level that could additionally explain the maintenance of chronic excess weight or the unsuccessful results of current treatments. To date, despite the growing evidence, the heterogeneity of the psychological evidence associated with obesity has made it challenging to generate consensus on whether these psycho-behavioural phenotypes can be a complement to improve outcomes of existing interventions. For this reason, this narrative review is an overview focused on summarizing studies describing the psycho-behavioural phenotypes associated with obesity. Based on the literature, three psychological constructs have emerged: reward dependence, cognitive control, and mood and emotion. We discuss the clinical implications of stratifying and identifying these psycho-behavioural profiles as potential target for interventions which may ensure a better response to treatment in individuals with obesity. Our conclusions pointed out a considerable overlap between these psycho-behavioural phenotypes suggesting bidirectional interactions between them. These findings endorse the complexity of the psycho-behavioural features associated with obesity and reinforce the need to consider them in order to improve treatment outcomes.

Body mass index, systemic inflammation and cognitive performance in adolescents: A cross-sectional study

BACKGROUND

Excessive body weight has been related to lower cognitive performance. One of the mechanisms through which excess body weight may affect cognition is inflammation.

HYPOTHESIS

Our hypothesis is that both body mass index (BMI) and circulating levels of inflammatory biomarkers will be negatively related to cognitive performance.

DESIGN

Cross-sectional study.

SETTING

Users of the public health centres of the Consorci Sanitari de Terrassa (Terrassa, Spain) between 2010 and 2017 aged 12-21 years.

PARTICIPANTS

One hundred and five adolescents (46 normoweight, 18 overweight, 41 obese).

MEASUREMENTS

Levels of high sensitivity C-reactive protein, interleukin 6, tumour necrosis factor α (TNFα) and fibrinogen were determined from blood samples. Cognitive performance was evaluated and six cognitive composites were obtained: working memory, cognitive flexibility, inhibitory control, decision-making, verbal memory, and fine motor speed. A single multivariate general lineal model was used to assess the influence of the four inflammatory biomarkers, as well as participants' BMI, sex, and age on the 6 cognitive indexes.

RESULTS

An inverse relationship between BMI and inhibitory control (F = 5.688, p = .019; β = -0.212, p = .031), verbal memory (F = 5.404, p = .022; β = -0.255, p = .009) and fine motor speed (F = 9.038, p = .003; β = -0.319, p = .001) was observed. Levels of TNFα and fibrinogen were inversely related to inhibitory control (F = 5.055, p = .027; β = -0.226, p = .021) and verbal memory (F = 4.732, p = .032; β = -0.274, p = .005), respectively.

LIMITATIONS

The cross-sectional nature of the study, the use of cognitive tests designed for clinical purposes, and the use of BMI as a proxy for adiposity are limitations of our study that must be taken into account when interpreting results.

CONCLUSIONS

Our data indicate that some components of executive functions, together with verbal memory, are sensitive to specific obesity-related inflammatory agents at early ages.

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.

Dysfunctional decision-making in binge-eating disorder: A meta-analysis and systematic review

Binge-Eating Disorder (BED) involves anticipatory craving and urges, subjective loss-of-control during binge-eating episodes, and post-feeding psychological distress and guilt. Evidence indicates neurocognitive dysfunctions contribute to BED onset, maintenance, and treatment response. However, an integrated understanding of how cognitive processes underpin BED symptomology is lacking. We utilised a multi-stage decision-making model defining ten cognitive processes underpinning Preference Formation, Choice Implementation, Feedback Processing, and Flexibility/Shifting, to comprehensively review research published since 2013. We used preregistered PICOS criteria to assess 1966 articles identified from PubMed, PsycInfo, and Scopus database searches. This yielded 50 studies reporting behavioural cognitive tasks outcomes, comparing individuals with BED to controls with normal and higher weight. Meta-analyses revealed a unique profile of cognitive dysfunctions that spanned all decision-making stages. Significant deficits were evident in Uncertainty Evaluation, Attentional Inhibition, Choice Consistency, and Cognitive Flexibility/Set-shifting. We propose a novel model of dysfunctional decision-making processes in BED and describe their role in binge-eating behaviour. We further highlight the potential for cognitive interventions to target these processes and address the significant treatment gap in BED.

Eating Disorders and Addictive Behaviors: Implications for Human Health

Eating disorders (EDs) are mental health diseases characterized by dysfunctional eating patterns, including restrictive eating, avoidance of foods, binge eating, and compensative behaviors to avoid weight increases and promote thinness (purging, vomiting, laxative/diuretics misuse, and compulsive exercise) [...].

Does virtual reality enhance the effects of inhibitory control training for loss-of-control eating? A pilot factorial experiment

Inhibitory control, one's ability to inhibit automatic responses to desirable stimuli, may be inadequately targeted in interventions for loss-of-control eating (LOC). Promising evidence has identified inhibitory control trainings (ICTs) as an avenue to target inhibitory control directly; however, effects of ICTs on real-world behavior are limited. Compared to typical computerized trainings, virtual reality (VR) presents several potential advantages that may address key shortcomings of traditional ICTs, i.e. poor approximation to everyday life. The present study utilized a 2 × 2 factorial design of treatment type (ICT vs sham) by treatment modality (VR vs standard computer), which allows for increased statistical power by collapsing across conditions. Our primary aim was to examine the feasibility and acceptability of six weeks of daily training among groups. A secondary aim was to preliminarily assess main and interactive effects of treatment type and modality on target engagement and efficacy (i.e., training compliance, change in LOC episodes, inhibitory control, and implicit liking of foods). Participants (N = 35) with ≥1×/weekly LOC were assigned to one of four conditions and completed ICTs daily for six weeks. The trainings were feasible and acceptable, evinced by high retention and compliance across time and condition. Although completing daily trainings across treatment types and modalities was associated with large decreases in LOC, there were no meaningful effects of either treatment type or modality, nor a significant interaction effect, on LOC or mechanistic variables. Future research should aim to increase the efficacy of ICT (both standard and VR-based) and test in fully-powered clinical trials.

Inhibitory control towards angry stimuli in patients with binge eating disorder: a pilot study

BACKGROUND

Emotion regulation theories and the negative urgency concept assume that negative mood increases binge eating. Negative emotions are considered as a trigger for binge eating, while binge eating itself is regarded as an impulsive behavior and should thus be increased within the negative urgency concept. Anger might be a specific negative emotion triggering binge eating in patients with binge eating disorder (BED). We investigated how inhibitory control as one main factor of impulsivity is influenced by anger stimuli in patients with BED and two control groups.

METHODS

We compared patients with BED (N = 20) with normal-weight healthy control participants (NW-CG, N = 20) and BMI-matched overweight and obese control participants (BMI-CG, N = 18). We used the emotional Stop Signal task (eSST) to investigate inhibitory control, where we presented angry facial expressions in comparison with neutral facial expressions as emotional stimuli.

RESULTS

All participants showed decreased inhibitory control in the angry versus neutral condition, i.e., a faster Stop Signal Reaction Time and a lower percentage of correct reactions. However, no significant group differences emerged in terms of performance. Performance in the eSST did not correlate with negative urgency, disorder- or emotion-related characteristics.

CONCLUSIONS

The current pilot study does not deliver evidence for decreased inhibitory control towards angry stimuli in patients with BED, as we detected a general and not disorder-related effect in all participants that might represent the conjunction of inhibitory control and anger. A direct mood induction technique might have led to different results. Further research in healthy and clinical groups is needed.

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 (βunstandardized = 0.33, p = .037, 95% CI [.02, 0.64]), but not baseline RRV-F (βunstandardized = -0.003, p = .914), 95% CI [-0.05, 0.05]) was significantly associated with 3-year adiposity such that those with the poorest food-related inhibitory control (great number of commision errors) had the greatest adiposity gain. The interaction between RRV-F and food-related inhibitory control did not predict 3-year adiposity (βunstandardized = -0.07, p = .648, 95% CI [-0.39, 0.25]). The pattern of findings was the same for models examining non-food related inhibitory control. Neither baseline food-related inhibitory control (βunstandardized = 2.16, p = .256, 95% CI [-1.59, 5.92]), baseline RRV-F (βunstandardized = 0.14, p = .660, 95% CI [-0.48, 0.75]), nor their interaction (βunstandardized = -1.18, p = .547, 95% CI [-5.04, 2.69]) were significantly associated with 3-year BMI. However, non-food related inhibitory control (βunstandardized = 0.54, 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 inhibitory control and reward systems, as well as other disinhibited eating behaviors/traits, may interact to promote excess weight gain over time in youth.

Obtaining long-term recovery: advances in optimizing treatment outcomes in patients with binge-eating disorder

INTRODUCTION

Binge-eating disorder (BED) is a complex and disabling eating disorder (ED) associated with considerable burden and impairments in quality of life and physical/mental health. It has been recognized as a formal ED category since 2013, however BED is still underdetected and undertreated.

AREAS COVERED

This review summarizes the advances in the understanding of the pathophysiology of BED as well as the evidence on the efficacy of the existing treatments. The authors searched Scopus, PubMed, ClinicalTrials.Gov, and ANZCTR with terms including 'assessment' OR 'treatment' OR 'diagnosis' OR 'mechanisms' AND 'binge eating' OR 'binge-eating disorder' for manuscripts published between January 2013 and April 2023.

EXPERT OPINION

Most of the trials on treatments of BED have been in people of high weight with weight loss as an outcome. Nevertheless, less is known about the treatment of this condition in people with body mass index (BMI) within the normal range where weight stabilization may be a more appropriate goal. Moreover, there is a need for an enhanced appreciation of the role of combination treatment to improve overall outcomes. Also, there are important opportunities for future research in understanding the mechanisms of action and effectiveness of BED treatments.