The Psychological Mechanism And Neural Basis Of The Influence Of Social Support On Overeating

As of 2022,globally,as many as 70 million people suffer from eating disorders,with approximately 2.1 million people affected in China.China has become the country with the highest number of deaths due to eating disorders worldwide.Overeating is a key symptom of several eating disorders(Leenaerts,Jongen,Ceccarini,Van Oudenhove,& Vrieze,2022).Investigating predictive factors and their impact mechanisms for reducing overeating is crucial for the treatment and prevention of individual eating disorders and the promotion of mental and physical well-being.Social support is defined as the resources available from an individual’s social network intended to enhance their coping abilities.Social support aids individuals in maintaining healthy lifestyles and plays a positive role in overcoming addictive behaviors related to eating and challenging eating habits.Research indicates a widespread lack of social support among eating disorder populations,and social support from family and friends predicts the risk of binge eating episodes(Eric Stice,Presnell,& Spangler,2002).However,previous studies have mainly focused on the role of social support in eating disorder symptoms,without considering excessive eating behavior in non-clinical populations.Moreover,research on the relationship between social support and eating behavior has mostly relied on questionnaire surveys,making it difficult to establish causality.Currently,only one experimental study has attempted to investigate the impact of social support on binge eating and unhealthy eating behaviors(Kwan & Gordon,2016),but this study’s manipulation of social support was not entirely successful,possibly due to not considering the role of interpersonal distance.Importantly,while there have been studies on the relationship between social support,spontaneous brain activity,and gray matter structure(Che,Wei,et al.,2014;Sato,Kochiyama,Uono,Sawada,& Yoshikawa,2020),no research has focused on the neural mechanisms of how social support influences overeating.Social support in reducing overeating may be achieved by its influence on negative emotions and food reward sensitivity.On one hand,interpersonal models of overeating suggest that good social relationships reduce negative emotions,thereby lowering overeating levels(Ivanova,Tasca,Hammond,et al.,2015).At the neural level,social support has been shown to significantly affect the structure and function of brain regions such as the amygdala,medial prefrontal cortex(m PFC),and posterior cingulate cortex(PCC),which are important for emotional responses and regulation.Therefore,social support may influence overeating through the emotion regulation neural circuit.On the other hand,the alternative reward hypothesis suggests that both social connections and material rewards are essential human survival resources,and rich social connections reduce the craving for material rewards(e.g.,food)(Carver,2004).At the neural level,social rewards activate brain regions related to reward processing,such as the ventral striatum(VS)and ventromedial prefrontal cortex(vm PFC),which are also responsible for processing material rewards.Hence,social support may predict overeating through behavioral and neural indicators related to reward sensitivity(Gu et al.,2019).This study uses a large-sample questionnaire survey,behavioral experiments,resting-state f MRI,task-state f MRI,structural MRI,and other techniques to explore the predictive effects of social support on overeating and investigate the psychological and neural mechanisms involved,including reducing negative emotions and promoting food reward sensitivity.Study 1 aims to investigate the relationship between social support and overeating as well as the psychological mechanisms using cross-sectional and longitudinal designs.Experiment 1 measures overeating in two independent samples of university students(Sample 1,N=496;Sample 2,N=685)using two questionnaire tools.The results reveal a significant negative correlation between social support and overeating,with a gender effect.In Experiment 2(N=479),a longitudinal mediation model is constructed using questionnaire data,and the results show that social support can reduce short-term and long-term overeating by decreasing individual negative emotions,indicating the long-term stability of the predictive relationship between negative emotions and social support in overeating.In Experiment 3(N=840),a food cue delay task is used to explore the mediating role of food reward sensitivity,and it is found that social support is negatively correlated with the processing reaction time of high-calorie food cues and positively correlated with overeating.In other words,higher levels of social support are associated with faster reactions to high-calorie food cues and lower levels of overeating.Study 2 builds upon Study 1 and investigates the causal effects of social support on overeating and its psychological mechanisms through laboratory research.In Experiment 4(N=138),individuals’ experiences of social support are manipulated in a stressful situation to examine the effects of different sources of social support on negative emotions and their impact on the choice of high and low-calorie foods.Experiment 4 successfully manipulated the perceived level of social support and found that receiving any form of social support can reduce perceived stress compared to receiving no social support.However,in terms of the effects on negative emotions and overeating,social support from real friends is more effective than support from strangers(staff),suggesting an interpersonal distance effect in the impact of social support on overeating.Importantly,negative emotions during Experiment 4 predicted subsequent high-calorie food choices but not low-calorie food choices,consistent with previous research indicating that negative emotions induce cravings for delicious foods.Experiment 5(N=136)builds on Experiment 4 by adding a food cue delay task during stress,using reaction time and accuracy to measure food reward sensitivity and including actual calorie intake as an indicator of overeating.Experiment 5 first confirms the results of Experiment 4,showing that friend support is more effective than no intervention,self-regulation,and stranger support in reducing individual overeating choices and extending this effect to actual food intake.However,Experiment 5 did not find a significant effect of social support on reaction time during food cue anticipation.Given the greater sensitivity of the neural activation measures in the food cue delay task,further research should be conducted using task-state f MRI.Study 3 explores the mechanisms by which social support affects brain activity and structure and predicts overeating.Experiment 6 uses task-state f MRI(N=58)to collect data on individuals’ brain activity while receiving social support and predicts subsequent overeating indicators based on the activation values of significant brain areas.The results indicate that social support from friends primarily activates the dorsal medial prefrontal cortex(dm PFC)and PCC,and the activation levels of the dm PFC and PCC significantly positively predict subsequent food quantity choices,indicating that social support primarily activates brain areas responsible for cognitive processing and emotional control,successfully regulating overeating behavior.In Experiment 7,using resting-state functional MRI data(N=496),the study examines the chain mediation pathway in which social support predicts overeating through the regulation of brain networks related to emotion and negative emotions.The results show that higher levels of social support are associated with stronger connectivity between the executive control network(ECN)and other brain networks.The strength of the ECN to salience network(SN)connectivity can predict negative emotions and,in turn,predict overeating.Enhanced ECN-SN network connectivity reflects effective emotional regulation,which further influences the implementation of subsequent unhealthy eating behavior regulatory strategies.In Experiment 8(N=58),task-state functional MRI is used to measure individuals’ brain activity during a food cue delay task in a stressful situation to investigate the effects of receiving or not receiving social support on brain activation during food reward anticipation.The study also examines how brain activation levels affect subsequent overeating choices and intake.The results show that individuals receiving social support activate more reward-related brain areas,such as the ventral striatum(VS)and ventromedial prefrontal cortex(vm PFC),during the anticipation of high-calorie foods compared to those not receiving support,and these brain areas significantly predict subsequent overeating levels.In Experiment 9,combining structural MRI data(N=1038),the study explores whether social support predicts overeating levels through gray matter volume in the brain.The results show a significant positive correlation between social support and gray matter volume in the dm PFC and vm PFC,and vm PFC predicts overeating levels,indicating that social support has a profound impact on the structure of brain regions responsible for reward information processing,manifested as changes in brain structure.In summary,social support inhibits overeating by reducing negative emotions and increasing food reward anticipation sensitivity.Neural evidence suggests that social support predicts overeating through the regulation of emotional neural circuits and brain activation during food reward processing.The dm PFC and vm PFC are brain regions influenced by social support and mediate the relationship between social support and overeating through various modalities.This study has several innovations: at the theoretical level,it combines the interpersonal model of overeating and the reward resource substitution hypothesis to construct a dual-path theoretical model of how social support influences overeating.It demonstrates that social support reduces overeating by increasing synchronization in emotion regulation circuits and activating reward-related brain areas,thereby reducing negative emotions and enhancing reward sensitivity.Gender and interpersonal distance moderate the relationship between social support and overeating.At the methodological level,various brain imaging techniques,including resting-state,structural,and task-state MRI,are applied to investigate the potential mechanisms of social support on overeating,providing multimodal neural evidence.At the applied value level,by distinguishing the sources of social support,it offers research methods for future precision interventions.It establishes a connection between social support and overeating through brain regions involved in reward information processing,providing targets for future neural interventions.