Acute responses to opioidergic blockade as a biomarker of hedonic eating among obese women enrolled in a mindfulness-based weight loss intervention trial

Bariatric-Metabolic Surgery is the Most Effective Intervention in Reducing Food Addiction Symptoms: A Systematic Review and Meta-Analysis

There are different treatments for food addiction (FA) symptomatology, but a comprehensive review with a meta-analysis to determine the most effective intervention is lacking. The aim of this review is to investigate the efficacy of pharmacological, behavioral, and bariatric-metabolic surgical interventions in reducing FA symptomatology. Meta-analyses including 15 studies in adults showed a significantly positive effect (std mean difference in FA symptoms before vs after intervention 0.72 (0.58-0.95)), with bariatric-metabolic surgical interventions showing the highest efficacy in improving FA symptoms (1.17 (0.58-1.76) before vs after intervention). The existing evidence suggests a beneficial effect of bariatric-metabolic surgical, pharmacological, and behavioral interventions, in that order, on FA symptomatology in people with overweight/obesity. Weight loss and behavioral and lifestyle changes after surgery may be determinants in improving FA symptomatology.

Psychological Support Strategies for Adults With Type 2 Diabetes in a Very Low-Carbohydrate Web-Based Program: Randomized Controlled Trial

BACKGROUND

A very low-carbohydrate (VLC) nutritional strategy may improve glycemic control and weight loss in adults with type 2 diabetes (T2D). However, the supplementary behavioral strategies that might be able to improve outcomes using this nutritional strategy are uncertain.

OBJECTIVE

This study aims to compare the impact of adding 3 different supplementary behavioral strategies to a web-based VLC diet intervention. To our knowledge, this is the first trial to randomize participants to different frequencies of dietary self-monitoring.

METHODS

The study included 112 overweight adults with T2D (hemoglobin A1c ≥6.5%) taking no antiglycemic medications or only metformin. They received a remotely delivered 12-month VLC diet intervention. Participants were randomly assigned through a full factorial 2×2×2 design to supplementary strategies: either daily or monthly dietary self-monitoring, either mindful eating training or not, and either positive affect skills training or not. Our research goal was to determine whether 3 different supplemental strategies had at least a medium effect size (Cohen d=0.5).

RESULTS

Overall, the VLC intervention led to statistically significant improvements in glycemic control (-0.70%, 95% CI -1.04% to -0.35%; P<.001), weight loss (-6.82%, 95% CI -8.57% to -5.08%; P<.001), and depressive symptom severity (Cohen d -0.67, 95% CI -0.92 to -0.41; P<.001). Furthermore, 30% (25/83) of the participants taking metformin at baseline reduced or discontinued their metformin. Only 1 Cohen d point estimate reached 0.5; daily (vs monthly) dietary self-monitoring had a worse impact on depressive symptoms severity (Cohen d=0.47, 95% CI -0.02 to 0.95; P=.06). None of the strategies had a statistically significant effect on outcomes. For changes in our primary outcome, hemoglobin A1c, the daily (vs monthly) dietary self-monitoring impact was 0.42% (95% CI -0.28% to 1.12%); for mindful eating, it was -0.47% (95% CI -1.15% to 0.22%); and for positive affect, it was 0.12% (95% CI -0.57% to 0.82%). Other results for daily (vs monthly) dietary self-monitoring were mixed, suggesting an increase in weight (0.98%) and depressive symptoms (Cohen d=0.47), less intervention satisfaction (Cohen d=-0.20), more sessions viewed (3.02), and greater dietary adherence (Cohen d=0.24). For mindful eating, the results suggested a benefit for dietary adherence (Cohen d=0.24) and intervention satisfaction (Cohen d=0.30). For positive affect, the results suggested a benefit for depressive symptoms (Cohen d=-0.32), the number of sessions viewed (3.68), dietary adherence (Cohen d=0.16), and intervention satisfaction (Cohen d=0.25).

CONCLUSIONS

Overall, our results support the use of a VLC diet intervention in adults with T2D. The addition of monthly (not daily) dietary self-monitoring, mindful eating, and positive affect skills training did not show a definitive benefit, but it is worth further testing.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03037528; https://clinicaltrials.gov/ct2/show/NCT03037528.

Food addiction, hormones and blood biomarkers in humans: A systematic literature review

BACKGROUND

Food addiction may play a role in rising obesity rates in connection with obesogenic environments and processed food availability, however the concept of food addiction remains controversial. While animal studies show evidence for addictive processes in relation to processed foods, most human studies are psychologically focussed and there is a need to better understand evidence for biological mechanisms of food addiction in humans. Several key hormones are implicated in models of food addiction, due to their key roles in feeding, energy metabolism, stress and addictive behaviours. This systematic literature review examines evidence for relationships between food addiction, hormones and other blood biomarkers.

METHODS

A series of literature searches was performed in Scopus, PsychInfo, MedLine, ProQuest, CINAHL and Web of Science. A total of 3111 articles were found, of which 1045 were duplicates. Articles were included if they contained a psychometric measurement of food addiction, such as the Yale Food Addiction Scale, as well as addressed the association between FA and hormones or blood biomarkers in humans. Articles were assessed for eligibility by two independent reviewers.

RESULTS

Sixteen studies were identified that examined relationships between food addiction and blood biomarkers, published between 2015 and 2021. Significant findings were reported for leptin, ghrelin, cortisol, insulin and glucose, oxytocin, cholesterol, plasma dopamine, thyroid stimulating hormone (TSH), haemoglobin A1c (HbA1c), triglyceride (TG), amylin, tumour necrosis factor alpha (TNF- α) and cholecystokinin (CCK). Methodological issues included small sample sizes and variation in obesity status, sex and mental health-related comorbidities. Due to methodological limitations, definite connections between FA, hormones and other blood biomarkers cannot yet be determined.

CONCLUSION

This systematic review identified preliminary evidence linking FA symptoms to hormones and other blood biomarkers related to feeding, addiction, and stress. However, due to the small number of studies and methodological limitations, further research is needed to evaluate biopsychosocial models of FA and to resolve controversies.

Evaluation and Treatment of Obesity and Its Comorbidities: 2022 Update of Clinical Practice Guidelines for Obesity by the Korean Society for the Study of Obesity

The goal of the 8th edition of the Clinical Practice Guidelines for Obesity is to help primary care physician provide safe, effective care to patients with obesity by offering evidence-based recommendations to improve the quality of treatment. The Committee for Clinical Practice Guidelines comprised individuals with multidisciplinary expertise in obesity management. A steering board of seven experts oversaw the entire project. Recommendations were developed as the answers to key questions formulated in patient/problem, intervention, comparison, outcomes (PICO) format. Guidelines underwent multi-level review and cross-checking and received endorsement from relevant scientific societies. This edition of the guidelines includes criteria for diagnosing obesity, abdominal obesity, and metabolic syndrome; evaluation of obesity and its complications; weight loss goals; and treatment options such as diet, exercise, behavioral therapy, pharmacotherapy, and bariatric and metabolic surgery for Korean people with obesity. Compared to the previous edition of the guidelines, the current edition includes five new topics to keep up with the constantly evolving field of obesity: diagnosis of obesity, obesity in women, obesity in patients with mental illness, weight maintenance after weight loss, and the use of information and communication technology-based interventions for obesity treatment. This edition of the guidelines features has improved organization, more clearly linking key questions in PICO format to recommendations and key references. We are confident that these new Clinical Practice Guidelines for Obesity will be a valuable resource for all healthcare professionals as they describe the most current and evidence-based treatment options for obesity in a well-organized format.

The impact of mindfulness meditation on social and moral behavior: Does mindfulness enhance other-oriented motivation or decrease monetary reward salience?

This perspective article provides an overview of the impact of mindfulness meditation (MM) on social and moral behavior. In mindfulness research, prosocial behavior has been operationalized as helping behavior, altruistic redistribution of funds, reparative behavior, or monetary donation. Studies concerning moral behavior are still scarce. Despite inconsistent evidence, several studies found a beneficial effect of mindfulness on prosocial outcomes (i.e., a higher propensity to spend or give away money for the sake of other individuals). However, since the employed tasks were reward-based, participants’ decisions also directly affected their own payoff by reducing it. Crucially, MM also affects self-control circuitry and reduces reward-seeking behaviors and reward salience by making rewards less tempting. We have discussed evidence suggesting how challenging it may be to dissociate the specific weight of enhanced other-oriented motivation from one of the decreased monetary reward salience in explaining meditators’ behavior. Future higher-quality studies are needed to address this open issue.

Obesity as a Condition Determined by Food Addiction: Should Brain Endocannabinoid System Alterations Be the Cause and Its Modulation the Solution?

Obesity is a complex disorder, and the number of people affected is growing every day. In recent years, research has confirmed the hypothesis that food addiction is a determining factor in obesity. Food addiction is a behavioral disorder characterized by disruptions in the reward system in response to hedonic eating. The endocannabinoid system (ECS) plays an important role in the central and peripheral control of food intake and reward-related behaviors. Moreover, both obesity and food addiction have been linked to impairments in the ECS function in various brain regions integrating peripheral metabolic signals and modulating appetite. For these reasons, targeting the ECS could be a valid pharmacological therapy for these pathologies. However, targeting the cannabinoid receptors with inverse agonists failed when used in clinical contexts as a consequence of the induction of affective disorders. In this context, new classes of drugs acting either on CB1 and/or CB2 receptors or on synthetic and degradation enzymes of endogenous cannabinoids are being studied. However, further investigation is necessary to find safe and effective treatments that can exert anti-obesity effects, normalizing reward-related behaviors without causing important adverse mood effects.

Tobacco withdrawal increases junk food intake: The role of the endogenous opioid system

BACKGROUND

The aims of this study were to 1) determine whether acute nicotine withdrawal increases the intake of junk food (high in salt, fat, and sugar) and 2) assess whether the endogenous opioid system is involved in junk food intake during nicotine withdrawal using naltrexone as a pharmacological probe.

METHODS

Smokers were randomly assigned to 24-hr withdrawal from tobacco products (n = 42) or smoking ad libitum (n = 34). A non-smoking group (n = 29) was included. Participants completed two laboratory sessions where a placebo or 50 mg of naltrexone was administered. At the end of each session, participants were given a tray of snack items that differed in high to low energy density and dimensions of salty, sweet, and fat. Self-reported mood and withdrawal measures were collected immediately before the snacks were offered. Generalized linear and logistic models were used to assess the effects of acute smoking withdrawal, drug, and sex on the intake of snack items and self-reported measures.

RESULTS

Choice and consumption of food items were impacted by smoking condition (withdrawal > ad lib smoking and non-smokers; p < .05), the opioid blockade (naltrexone < placebo; p < .05), and sex (male > female; p < .05). The effects were evidenced in high sweet and high fat foods. No differences were found in low sweet and fat foods.

CONCLUSIONS

These findings extend earlier studies indicating impact of tobacco use on appetite, and identify the regulatory influence of the endogenous opioid system on appetite during nicotine withdrawal.

Exploratory Analysis of Racial/Ethnic and Educational Differences in a Randomized Controlled Trial of a Mindfulness-Based Weight Loss Intervention

OBJECTIVE

People of color and lower socioeconomic groups have higher obesity prevalence, lose less weight compared with Whites and higher socioeconomic groups, and are underrepresented in randomized controlled trials of mindfulness-based interventions. We examined whether mindfulness approaches reduce disparities in weight loss interventions.

METHODS

We analyzed data from a randomized controlled trial of 194 participants with obesity (41% participants of color, 36% without college degree) comparing a 5.5-month mindfulness-based weight loss intervention to an active-control with identical diet-exercise guidelines. We assessed attendance, 18-month attrition, and weight change at 6, 12, and 18 months by race/ethnicity and education level using linear mixed models, adjusting for baseline body mass index, age, and education or race/ethnicity, respectively.

RESULTS

Participants without versus with a college degree attended fewer sessions and had higher attrition across interventions. Participants of color attended fewer intervention sessions in the mindfulness compared with the control intervention. Overall, participants of color lost significantly less weight at 12 and 18 months compared with Whites. However, during the 6- to 18-month maintenance period, we found an interaction of intervention arm, race/ethnicity, and time (p = .035), indicating that participants of color compared with Whites regained more weight in the control (0.33 kg/mo; p = .005) but not mindfulness intervention (0.06 kg/mo; p = .62). Participants without a college degree had greater initial weight loss in the mindfulness compared to control intervention from 0 to 6 months (-0.46 kg/mo; p = .039).

CONCLUSIONS

Although disparities persist, mindfulness approaches may mitigate some racial/ethnic and socioeconomic differences in weight loss compared with conventional diet-exercise programs.Trial Registration: Clinicaltrials.gov registration: NCT00960414.

Current Intervention Treatments for Food Addiction: A Systematic Review

Research on the concept of food addiction (FA) has steadily grown and, based on a widely used self-report, FA is estimated to affect between 16-20% of the adult population. However, there are few interventions available for people with self-reported FA, and their efficacy is unclear. The primary aim of the review was to examine the efficacy of different interventions, including behavioural/lifestyle, medication and surgical approaches, for reducing symptoms and/or changing diagnosis of FA among adolescents and adults. A secondary aim was to examine the influence of sex as a moderator of intervention effects. A systematic search was performed from 2008-2020 to identify studies that used the YFAS to assess the effectiveness of interventions on FA. Nine studies were identified (n = 7 adults, n = 2 adolescents) including a total of 812 participants (range 22-256) with an average of 69% females per study. The types of interventions included medications (n = 3), lifestyle modification (n = 3), surgical (n = 2) and behavioural (n = 1), with FA being assessed as a secondary outcome in all studies. Five studies in adults reported a significant reduction in FA symptoms or diagnosis from pre to post-intervention, two when compared to a control group and three in the intervention group only. Efficacious interventions included: medication (combination of naltrexone and bupropion, as well as pexacerfont), bariatric surgery and lifestyle modification. No significant changes in FA were reported in adolescent studies. Given few studies were identified by the review, there is insufficient evidence to provide clear recommendations for practice; however, some interventions show potential for reducing self-reported FA outcomes in adults. Future research should explore the longer-term efficacy of interventions and the effectiveness of treatments with sufficient sample sizes.

Converging vulnerability factors for compulsive food and drug use

Highly palatable foods and substance of abuse have intersecting neurobiological, metabolic and behavioral effects relevant for understanding vulnerability to conditions related to food (e.g., obesity, binge eating disorder) and drug (e.g., substance use disorder) misuse. Here, we review data from animal models, clinical populations and epidemiological evidence in behavioral, genetic, pathophysiologic and therapeutic domains. Results suggest that consumption of highly palatable food and drugs of abuse both impact and conversely are regulated by metabolic hormones and metabolic status. Palatable foods high in fat and/or sugar can elicit adaptation in brain reward and withdrawal circuitry akin to substances of abuse. Intake of or withdrawal from palatable food can impact behavioral sensitivity to drugs of abuse and vice versa. A robust literature suggests common substrates and roles for negative reinforcement, negative affect, negative urgency, and impulse control deficits, with both highly palatable foods and substances of abuse. Candidate genetic risk loci shared by obesity and alcohol use disorders have been identified in molecules classically associated with both metabolic and motivational functions. Finally, certain drugs may have overlapping therapeutic potential to treat obesity, diabetes, binge-related eating disorders and substance use disorders. Taken together, data are consistent with the hypotheses that compulsive food and substance use share overlapping, interacting substrates at neurobiological and metabolic levels and that motivated behavior associated with feeding or substance use might constitute vulnerability factors for one another. This article is part of the special issue on 'Vulnerabilities to Substance Abuse'.

Safety and efficacy of naltrexone for weight loss in adult patients - a systematic review

INTRODUCTION

This is a report of a systematic review of the safety and efficacy of naltrexone or naltrexone/bupropion on weight loss.

MATERIAL AND METHODS

The databases Medline, PubMed, and Embase as well as the Cochrane Controlled Trials Register for randomized controlled trials were searched for studies published from January 1966 to January 2018. A meta-analysis, randomised controlled trials, controlled trials, uncontrolled trials, cohort studies and open-label studies were analysed.

RESULTS

Of 191 articles, 14 fulfilled the inclusion criteria: 1 meta-analysis, 10 randomized controlled trials, and 3 studies without randomization were found. In these studies, the efficacy and safety of naltrexone/bupropion in obesity were analysed. In the majority of these studies, patients with at least 5% or 10% weight loss, as a primary outcome, were investigated. Generally, naltrexone/bupropion treatment can be a promising therapy for obese patients, including when combined with mental health treatment.

CONCLUSIONS

Based on these studies, it can be said that naltrexone/bupropion treatment is effective in the weight loss of overweight subjects. The naltrexone/bupropion treatment was well tolerated by the patients, and side effects were rarely reported.

Ultraprocessed Food: Addictive, Toxic, and Ready for Regulation

Past public health crises (e.g., tobacco, alcohol, opioids, cholera, human immunodeficiency virus (HIV), lead, pollution, venereal disease, even coronavirus (COVID-19) have been met with interventions targeted both at the individual and all of society. While the healthcare community is very aware that the global pandemic of non-communicable diseases (NCDs) has its origins in our Western ultraprocessed food diet, society has been slow to initiate any interventions other than public education, which has been ineffective, in part due to food industry interference. This article provides the rationale for such public health interventions, by compiling the evidence that added sugar, and by proxy the ultraprocessed food category, meets the four criteria set by the public health community as necessary and sufficient for regulation—abuse, toxicity, ubiquity, and externalities (How does your consumption affect me?). To their credit, some countries have recently heeded this science and have instituted sugar taxation policies to help ameliorate NCDs within their borders. This article also supplies scientific counters to food industry talking points, and sample intervention strategies, in order to guide both scientists and policy makers in instituting further appropriate public health measures to quell this pandemic.

Adolescents Living with Food Allergies in Select Global Cities: Does a WhatsApp-Based Mindful Eating Intervention Promote Wellbeing and Enhance their Self-Concept?

PURPOSE

Food allergy prevalence in children and adolescents is increasing globally. Dietary restrictions are linked to the identities of food-allergic adolescents, which influences their wellbeing and self-concept. Mindful eating (ME) has been widely used to treat eating disorders. This study investigates whether WhatsApp-based mindful eating (ME) posts are effective for food-allergic adolescents in managing the condition, building self-concept and wellbeing.

DESIGN AND METHODS

A waitlist control design study was conducted with food-allergic adolescents (N _pre-test = 244; N _post-test = 215). Three measures were used to assess the outcomes pre- (T1) and post-test (T2): Mindful Eating Questionnaire (MEQ), Brief Psychological Wellbeing Scale for Adolescents (BPWBS-A), and Piers-Harris 2 Children's Self-Concept Scale (PH-2-CSCC).

RESULTS

The intervention was overall effective and more so for girls, middle class adolescents, with mothers as primary caregivers, whose primary caregivers had higher or postgraduate and professional qualifications, who were in turn also more likely to report no anaphylactic reaction and hospitalization emergency episodes at T2. Intervention compliance mediated the association between demographic predictors and outcome scores. Discriminant function analysis indicated stronger associations between certain predictors and subdomains of the self-concept outcome.

CONCLUSIONS

With adequate emphasis on intervention compliance and condition management, the WhatsApp-based ME posts would be effective for food-allergic adolescents.

PRACTICAL IMPLICATIONS

Pediatric nurses can recommend the intervention for community-dwelling food-allergic adolescents across contexts. Some refinements may be needed for boys, upper class adolescents, with father/kin as primary caregivers and less qualified parents.

Identifying stress-related eating in behavioural research: A review

Stress is a commonly reported precipitant of overeating. Understanding the relationship between stress and food intake is important, particularly in view of the increasing prevalence of obesity. The purpose of this review is to examine how stress-related eating has been defined and measured in the literature to date. There are no established diagnostic criteria or gold standards for quantification of stress-related eating. Questionnaires relying on the accuracy of self-report are the mainstay of identifying people who tend to eat in response to stress and emotions. There is a paucity of clinical research linking objective measurements of stress and appetite with self-reported eating behaviour. Limitations of the methodological approaches used and the heterogeneity between studies leave significant knowledge gaps in our understanding of the mechanism of stress related eating, and how best to identify it. These issues are discussed, and areas for further research are explored.

Stress as a potential moderator of ovarian hormone influences on binge eating in women

Previous research has demonstrated significant associations between increased levels of ovarian hormones and increased rates of binge eating (BE) in women. However, whereas all women experience fluctuations in ovarian hormones across the menstrual cycle, not all women binge eat in response to these fluctuations, suggesting that other factors must contribute. Stress is one potential contributing factor. Specifically, it may be that hormone-BE associations are stronger in women who experience high levels of stress, particularly as stress has been shown to be a precipitant to BE episodes in women. To date, no studies have directly examined stress as a moderator of hormone-BE associations, but indirect data (that is, associations between BE and stress and between ovarian hormones and stress) could provide initial clues about moderating effects. Given the above, the purpose of this narrative review was to evaluate these indirect data and their promise for understanding the role of stress in hormone-BE associations. Studies examining associations between all three phenotypes (that is, ovarian hormones, stress, and BE) in animals and humans were reviewed to provide the most thorough and up-to-date review of the literature on the potential moderating effects of stress on ovarian hormone-BE associations. Overall, current evidence suggests that associations between hormones and BE may be stronger in women with high stress levels, possibly via altered hypothalamic-pituitary-adrenal axis response to stress and increased sensitivity to and altered effects of ovarian hormones during stress. Additional studies are necessary to directly examine stress as a moderator of ovarian hormone-BE associations and identify the mechanisms underlying these effects.

Systematic Review of Food Addiction as Measured with the Yale Food Addiction Scale: Implications for the Food Addiction Construct

BACKGROUND

The concept of food addiction attracts much interest in the scientific community. Research is mainly based on the Yale Food Addiction Scale (YFAS), a tool developed to assess food addiction. Substance use disorder criteria have been used to develop this scale.

OBJECTIVE

The aim of this paper was to review the clinical significance of food addiction diagnoses made with the YFAS and to discuss the results in light of the current debate on behavioral addictions.

METHODS

We performed a systematic review of the studies that assessed food addiction with the YFAS published between January 2014 and July 2017 by searching the electronic databases PsycINFO, MEDLINE, and PsycARTICLES.

RESULTS

Sixty publications were included in the analysis. Thirty-three studies examined nonclinical samples and 27 examined clinical samples. All studies used YFAS scoring results to define food addiction. The prevalence of food addiction according to the YFAS varied largely by the studied samples. In general, a higher body mass index and the presence of eating disorders (EDs), especially binge eating disorder (BED), were associated with higher YFAS scores.

CONCLUSION

The concept of food addiction has not been established to this day although it can be grouped with other EDs such as BED. More research is needed to understand this behavior and the differences between food addiction and other EDs. The criteria for food addiction should be revisited in light of the concepts currently used to examine behavioral addictions.

A structured literature review on the role of mindfulness, mindful eating and intuitive eating in changing eating behaviours: effectiveness and associated potential mechanisms

The role of mindfulness, mindful eating and a newer concept of intuitive eating in modulating eating habits is an area of increasing interest. In this structured literature review, a summary of the current evidence is presented, together with details of interventions undertaken and the tools to measure outcomes. It is broad in scope given the emerging evidence base in this area. The review yielded sixty-eight publications: twenty-three interventions in obese/overweight populations; twenty-nine interventions in normal-weight populations; sixteen observational studies, three of which were carried out in overweight/obese populations. Mindfulness-based approaches appear most effective in addressing binge eating, emotional eating and eating in response to external cues. There is a lack of compelling evidence for the effectiveness of mindfulness and mindful eating in weight management. Mindfulness-based approaches may prevent weight gain. Reduced food intake was seen in some of the studies in overweight and obese populations, but this was less apparent in the studies in normal-weight populations. The evidence base for intuitive eating is limited to date and further research is needed to examine its potential in altering eating behaviours. Mindfulness appears to work by an increased awareness of internal, rather than external, cues to eat. Mindfulness and mindful eating have the potential to address problematic eating behaviours and the challenges many face with controlling their food intake. Encouraging a mindful eating approach would seem to be a positive message to be included in general weight management advice to the public.

The effectiveness of naltrexone combined with current smoking cessation medication to attenuate post smoking cessation weight gain: a literature review

Background

Smoking is the number one cause of preventable morbidity and mortality globally and although many countries have invested heavily in smoking cessation programs, 21% of the global population still smoke. Post cessation weight gain has been identified as a barrier to attempting cessation and is implicated in the high rates of relapse. Naltrexone has been touted as a possible solution to address post smoking cessation weight gain.

Results

The results from seven original studies assessing the effectiveness of naltrexone in combination with existing smoking cessation medications to attenuate post smoking cessation weight gain were obtained and critically reviewed. Five returned positive results and two returned results that were statistically insignificant. The positive results were seen more often in those identified as more likely to exhibit hedonic eating behaviour for example women and participants who were categorised as overweight or obese.

Conclusion

The evidence suggests further investigation in to a combination of naltrexone and approved smoking cessation medications is warranted and could provide a solution to attenuate post smoking cessation weight gain especially in women and those classified as overweight or obese. This may provide the tool required to remove a perceived barrier to smoking cessation and improve global statistics.

Making sense of metabolic obesity and hedonic obesity

Body weight is neither stationary nor does it change unidirectionally. Rather, body weight usually oscillates up and down around a set point. Two types of forces determine the direction of weight changes. Forces that push body weight away from the set point are defined as non-homeostatic and are governed by multiple mechanisms, including, but not limited to, hedonic regulation of food intake. Forces that restore the set point weight are defined as homeostatic, and they operate through mechanisms that regulate short-term energy balance driven by hunger and satiation and long-term energy balance driven by changes in adiposity. In the normal physiological state, the deviation of body weight from the set point is usually small and temporary, and is constantly corrected by homeostatic forces. Metabolic obesity develops when body weight set point is shifted to an abnormally high level and the obese body weight becomes metabolically defended. In hedonic obesity, the obese body weight is maintained by consistent overeating due to impairments in the reward system, although the set point is not elevated. Adaptive increases in energy expenditure are elicited in hedonic obesity because body weight is elevated above the set point. Neither subtype of obesity undergoes spontaneous resolution unless the underlying disorders are corrected. In this review, the need for both appropriate patient stratification and tailored treatments is discussed in the context of the new framework of metabolic and hedonic obesity.

Improving Assessment of the Spectrum of Reward-Related Eating: The RED-13

A diversity of scales capture facets of reward-related eating (RRE). These scales assess food cravings, uncontrolled eating, addictive behavior, restrained eating, binge eating, and other eating behaviors. However, these scales differ in terms of the severity of RRE they capture. We sought to incorporate the items from existing scales to broaden the 9-item Reward-based Eating Drive scale (RED-9; Epel et al., 2014), which assesses three dimensions of RRE (lack of satiety, preoccupation with food, and lack of control over eating), in order to more comprehensively assess the entire spectrum of RRE. In a series of 4 studies, we used Item Response Theory models to consider candidate items to broaden the RED-9. Studies 1 and 2 evaluated the abilities of additional items from existing scales to increase the RED-9's coverage across the spectrum of RRE. Study 3 evaluated candidate items identified in Studies 1 and 2 in a new sample to assess the extent to which they accounted for more variance in areas less well-covered by the RED-9. Study 4 tested the ability of the RED-13 to provide consistent coverage across the range of the RRE spectrum. The resultant RED-13 accounted for greater variability than the RED-9 by reducing gaps in coverage of RRE in middle-to-low ranges. Like the RED-9, the RED-13 was positively correlated with BMI. The RED-13 was also positively related to a diagnosis of type 2 diabetes as well as cravings for sweet and savory foods. In summary, the RED-13 is a brief self-report measure that broadly captures the spectrum of RRE and may be a useful tool for identifying individuals at risk for overweight or obesity.

Endogenous Opiates and Behavior: 2015

This paper is the thirty-eighth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2015 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.

Keeping Weight Off: study protocol of an RCT to investigate brain changes associated with mindfulness-based stress reduction

INTRODUCTION

Obesity is a growing epidemic fuelled by unhealthy behaviours and associated with significant comorbidities and financial costs. While behavioural interventions produce clinically meaningful weight loss, weight loss maintenance is challenging. This may partially be due to failure to target stress and emotional reactivity. Mindfulness-based stress reduction (MBSR) reduces stress and emotional reactivity and may be a useful tool for behaviour change maintenance. This study seeks to provide a mechanistic understanding for clinical trials of the benefits of MBSR for weight loss maintenance by examining changes in functional connectivity (FC) and the association of these changes with clinical outcomes.

METHODS AND ANALYSIS

Community-dwelling individuals (n=80) who intentionally lost ≥5% of their body weight in the past year will be recruited and randomised to an MBSR programme or educational control. FC using resting-state functional MRI will be measured at baseline and 8 weeks. Psychological factors, health behaviours, body mass index and waist circumference will be measured at baseline, 8 weeks and 6 months post intervention. A 12-month telephone follow-up will assess self-reported weight. Analyses will characterise FC changes in response to MBSR in comparison with a control condition, assess the relationship between baseline FC status and pre-post MBSR changes in FC and investigate the association of FC change with changes in psychological factors and weight loss maintenance.

ETHICS AND DISSEMINATION

The University of Massachusetts Medical School Institutional Review Board has approved this study, Declaration of Helsinki protocols are being followed, and patients will give written informed consent. The Independent Monitoring Committee will monitor protocol adherence. Results from the study will be disseminated to the medical community at conferences and submitted for publication in peer-reviewed journals when the last patient included has been followed up for 12 months.

TRIAL REGISTRATION NUMBER

NCT02189187.

Effects of Mindfulness-Based Interventions on Salivary Cortisol in Healthy Adults: A Meta-Analytical Review

Objective: The aim of the present study was to elucidate the effects of Mindfulness-based interventions (MBIs) on salivary cortisol levels in healthy adult populations.

Method: We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs), published between January 1980 and June 2015 in PubMed, EMBASE, PsycINFO and the Cochrane library. The PRISMA and Cochrane guidelines were followed. The pooled effect sizes were calculated with the random-effects model, using Hedges' g-values, and heterogeneity was measured using the I² statistic. The contribution of different characteristics of participants and programmes were assessed by meta-regression models, using beta coefficients.

Results: Five RCTs with 190 participants in total were included in this systematic review. The overall effect size (ES) for improving the state of health related to cortisol levels was moderately low (g = 0.41; p = 0.025), although moderate heterogeneity was found (I² = 55; p = 0.063). There were no significant differences between active (g = 0.33; p = 0.202) and passive (g = 0.48; p = 0.279) controls, but significant differences were found when comparing standard (g = 0.81; p = 0.002) and raw (g = 0.03; p = 0.896) measures. The percentage of women in each study was not related to ES. Nevertheless, age (beta = −0.03; p = 0.039), the number of sessions (beta = 0.33; p = 0.007) and the total hours of the MBI (beta = 0.06; p = 0.005) were significantly related to ES, explaining heterogeneity (R² = 1.00).

Conclusions: Despite the scarce number of studies, our results suggest that MBIs might have some beneficial effect on cortisol secretion in healthy adult subjects. However, there is a need for further RCTs implemented in accordance with standard programmes and measurements of salivary cortisol under rigorous strategies in healthy adult populations.

Examination of the reliability and validity of the Mindful Eating Questionnaire in pregnant women

OBJECTIVE

Mindfulness is theorized to affect the eating behavior and weight of pregnant women, yet no measure has been validated during pregnancy.

METHODS

This study qualitatively and quantitatively evaluated the reliability and validity of the Mindful Eating Questionnaire (MEQ) in overweight and obese pregnant women. Participants completed focus groups and cognitive interviews. The MEQ was administered twice to measure test-retest reliability. The Eating Inventory (EI) and Mindful Attention Awareness Scale (MAAS) were administered to assess convergent validity, and the Neighborhood Environment Walkability Scale (NEWS) assessed discriminant validity.

RESULTS

Participants were 20 ± 8 weeks gestation (mean ± SD), 30 ± 2 years old, and 55% were obese. The MEQ total score had good test-retest reliability (r = .85). The total score internal consistency reliability was poor (Cronbach's α = .56). The external cues subscale (ECS) was not internally consistent (α = .31). Other subscales ranged from α = .59-.68. When the ECS was excluded, the MEQ total score internal consistency was acceptable (α = .62). Convergent validity was supported by the MEQ total score (with and without ECS) correlating significantly with the MAAS and the EI disinhibition and hunger subscales. Discriminant validity of the MEQ was supported by the MEQ and NEWS total scores and subscales not being significantly correlated. The quantitative results were supported by the qualitative context and content analysis.

CONCLUSION

With the exception of the ECS, the MEQ's reliability and validity was supported in pregnant women, and most of the subscales were more robust in pregnant women than in the original sample of healthy adults. The MEQ's use with overweight and obese pregnant women is supported.

Reduced reward-driven eating accounts for the impact of a mindfulness-based diet and exercise intervention on weight loss: Data from the SHINE randomized controlled trial

Many individuals with obesity report over eating despite intentions to maintain or lose weight. Two barriers to long-term weight loss are reward-driven eating, which is characterized by a lack of control over eating, a preoccupation with food, and a lack of satiety; and psychological stress. Mindfulness training may address these barriers by promoting awareness of hunger and satiety cues, self-regulatory control, and stress reduction. We examined these two barriers as potential mediators of weight loss in the Supporting Health by Integrating Nutrition and Exercise (SHINE) randomized controlled trial, which compared the effects of a 5.5-month diet and exercise intervention with or without mindfulness training on weight loss among adults with obesity. Intention-to-treat multiple mediation models tested whether post-intervention reward-driven eating and psychological stress mediated the impact of intervention arm on weight loss at 12- and 18-months post-baseline among 194 adults with obesity (BMI: 30-45). Mindfulness (relative to control) participants had significant reductions in reward-driven eating at 6 months (post-intervention), which, in turn, predicted weight loss at 12 months. Post-intervention reward-driven eating mediated 47.1% of the total intervention arm effect on weight loss at 12 months [β = -0.06, SE(β) = 0.03, p = .030, 95% CI (-0.12, -0.01)]. This mediated effect was reduced when predicting weight loss at 18 months (p = .396), accounting for 23.0% of the total intervention effect, despite similar weight loss at 12 months. Psychological stress did not mediate the effect of intervention arm on weight loss at 12 or 18 months. In conclusion, reducing reward-driven eating, which can be achieved using a diet and exercise intervention that includes mindfulness training, may promote weight loss (clinicaltrials.gov registration: NCT00960414).

Examining the mediating roles of binge eating and emotional eating in the relationships between stress and metabolic abnormalities

To test whether binge eating and emotional eating mediate the relationships between self-reported stress, morning cortisol and the homeostatic model of insulin resistance and waist circumference. We also explored the moderators of gender and age. Data were from 249 adults (mean BMI = 26.9 ± 5.1 kg/m(2); mean age = 28.3 ± 8.3 years; 54.2% male; 69.5% white) recruited from the community who were enrolled in a cross-sectional study. Participants completed a comprehensive assessment panel of psychological and physiological assessments including a morning blood draw for plasma cortisol. We found negative relationships between stress and morning cortisol (r = -0.15 to -0.21; p < 0.05), and cortisol and the homeostatic model of insulin resistance and waist circumference (r = -0.16, -0.25, respectively; p < 0.05). There was not statistical support for binge eating or emotional eating as mediators and no support for moderated mediation for either gender or age; however, gender moderated several paths in the model. These include the paths between perceived stress and emotional eating (B = 0.009, p < 0.001), perceived stress and binge eating (B = 0.01, p = 0.003), and binge eating and increased HOMA-IR (B = 0.149, p = 0.018), which were higher among females. Among women, perceived stress may be an important target to decrease binge and emotional eating. It remains to be determined what physiological and psychological mechanisms underlie the relationships between stress and metabolic abnormalities.

Putting the brakes on the "drive to eat": Pilot effects of naltrexone and reward-based eating on food cravings among obese women

PURPOSE

Obese individuals vary in their experience of food cravings and tendency to engage in reward-driven eating, both of which can be modulated by the neural reward system rather than physiological hunger. We examined two predictions in a sample of obese women: (1) whether opioidergic blockade reduced food-craving intensity, and (2) whether opioidergic blockade reduced an association between food-craving intensity and reward-driven eating, which is a trait-like index of three factors (lack of control over eating, lack of satiation, preoccupation with food).

METHODS

Forty-four obese, pre-menopausal women completed the Reward-Based Eating Drive (RED) scale at study start and daily food-craving intensity on 5 days on which they ingested either a pill-placebo (2 days), a 25 mg naltrexone dose (1 day), or a standard 50mg naltrexone dose (2 days).

RESULTS

Craving intensity was similar under naltrexone and placebo doses. The association between food-craving intensity and reward-driven eating significantly differed between placebo and 50mg naltrexone doses. Reward-driven eating and craving intensity were significantly positively associated under both placebo doses. As predicted, opioidergic blockade (for both doses 25mg and 50mg naltrexone) reduced the positive association between reward-driven eating and craving intensity to non-significance.

CONCLUSIONS

Opioidergic blockade did not reduce craving intensity; however, blockade reduced an association between trait-like reward-driven eating and daily food-craving intensity, and may help identify an important endophenotype within obesity.