Habitual behavioural control moderates the relation between daily perceived stress and purging.

OBJECTIVE: Evidence suggests that interpersonal stress plays a role in maintaining binge eating and purging (e.g., self-induced vomiting, misuse of laxatives). Stress is especially likely to promote engagement in maladaptive behaviour if the behaviour is habitual; therefore, individuals whose binge eating and/or purging are habitual may be particularly likely to engage in these behaviours in the context of interpersonal stress. We aimed to investigate this hypothesis in a sample of women with binge eating and/or purging using ecological momentary assessment (EMA). METHOD: Women (N = 81) with binge-eating and/or purging symptoms completed a self-report measure assessing habit strength of binge eating and purging followed by a 14-day EMA protocol assessing daily perceived interpersonal stress and binge-eating and purging episodes. RESULTS: Habit strength of purging moderated the within-person effect of interpersonal stress on purging frequency, such that higher daily stress was associated with greater same-day purging frequency when purging was more habitual. Contrary to expectations, the interactive effect of habit strength of binge eating and daily interpersonal stress on same-day binge-eating frequency was non-significant. CONCLUSIONS: Findings suggest that individuals with habitual purging may be vulnerable to engaging in purging when they are experiencing high levels of interpersonal stress.

Disordered eating in transgender and gender non-conforming youth: A comparison to community-based and clinical samples.

OBJECTIVE: This study investigates eating pathology in transgender and gender non-conforming (TGNC) youth compared to a community-based sample and individuals with eating disorders (EDs). METHOD: Participants (ages 13-21 years) included TGNC youth from a paediatric gender clinic (N = 97), a demographically matched community-based sample of cisgender males (N = 97) and cisgender females (N = 97), and treatment-seeking patients with EDs (N = 112). The Eating Disorder Examination Questionnaire (EDE-Q) was used to assess ED cognitions and behaviours. RESULTS: Transgender and gender non-conforming participants reported significantly higher EDE-Q global scores compared to the cisgender samples, but significantly lower than the ED sample. Transgender and gender non-conforming individuals reported a higher likelihood of objective binge episodes (OBEs) than the cisgender groups, albeit lower than youth with EDs. A substantial proportion of TGNC participants scored in elevated ranges on the EDE-Q global score (35% ≥ score of 3, 17% ≥ score of 4), significantly higher than cisgender males (0% ≥ score of 3, 0% ≥ score of 4) and females (9% ≥ score of 3, 3% ≥ score of 4). CONCLUSIONS: Findings indicate that TGNC youth exhibit increased ED cognitions and OBEs compared to cisgender samples, highlighting the need for screening and addressing ED symptoms in this population.

Disentangling the links between gastric emptying and binge eating v. purging in eating disorders using a case-control design.

BACKGROUND: Prior work supports delayed gastric emptying in anorexia nervosa and bulimia nervosa (BN) but not binge-eating disorder, suggesting that neither low body weight nor binge eating fully accounts for slowed gastric motility. Specifying a link between delayed gastric emptying and self-induced vomiting could offer new insights into the pathophysiology of purging disorder (PD). METHODS: Women (N = 95) recruited from the community meeting criteria for DSM-5 BN who purged (n = 26), BN with nonpurging compensatory behaviors (n = 18), PD (n = 25), or healthy control women (n = 26) completed assessments of gastric emptying, gut peptides, and subjective responses over the course of a standardized test meal under two conditions administered in a double-blind, crossover sequence: placebo and 10 mg of metoclopramide. RESULTS: Delayed gastric emptying was associated with purging with no main or moderating effects of binge eating in the placebo condition. Medication eliminated group differences in gastric emptying but did not alter group differences in reported gastrointestinal distress. Exploratory analyses revealed that medication caused increased postprandial PYY release, which predicted elevated gastrointestinal distress. CONCLUSIONS: Delayed gastric emptying demonstrates a specific association with purging behaviors. However, correcting disruptions in gastric emptying may exacerbate disruptions in gut peptide responses specifically linked to the presence of purging after normal amounts of food.

The role of habit in maintaining binge/purge behaviors: An ecological momentary assessment study.

OBJECTIVE: Individuals with eating disorders transdiagnostically engage in binge eating (BE) and/or purging, despite life-threatening consequences. Little is known about factors that contribute to the persistence of these behaviors. This study explored whether habitual control over binge/purge (B/P) spectrum behaviors contributes to symptom persistence and whether negative reinforcement via reductions in negative affect is less influential in maintaining B/P behaviors that are under habitual control and are persistent. METHOD: Women with BE and/or purging (N = 81) completed self-report measures assessing habit strength of BE and purging. Then, they completed a 14-day ecological momentary assessment (EMA) protocol during which they completed measures of negative affect, BE, and purging multiple times per day. RESULTS: Habitual control over purging was associated with a greater frequency of purging during the EMA period. However, habitual control over BE was not associated with the severity of loss of control eating or the frequency of BE episodes. Habitual control did not moderate temporal relations between negative affect and B/P behaviors during the EMA period. However, exploratory analyses revealed that individuals with a longer duration of BE and greater habitual control over BE showed a less pronounced reduction in negative affect following BE. DISCUSSION: Overall, these findings suggest that purging may be maintained by habitual stimulus-response learning. In addition, they support the possibility that reduction in negative affect may play a less prominent role in maintaining BE that is habitual and persistent. PUBLIC SIGNIFICANCE: This study investigated whether habit contributes to the persistence of symptoms in women with binge/purge spectrum behaviors and whether negative reinforcement via reductions in negative affect is less influential in maintaining binge/purge behaviors that are under habitual control. The findings suggest that purging may be maintained through habit. This supports the potential utility of habit reversal interventions to decrease habitual purging.

Reconceptualizing emotion regulation and coping strategy usage in eating disorders research: The utility of a regulatory flexibility framework.

Emotion regulation and coping strategies are often conceptualized in eating disorder (ED) research as inherently adaptive or maladaptive, and successful regulation is often defined as greater overall use of adaptive strategies. However, recent empirical work outside of the field of EDs challenges this categorical conceptualization of strategies, demonstrating that adaptiveness is determined by the ability to flexibly implement and adjust strategies based on contextual demands (i.e., regulatory flexibility). Despite evidence that emotion regulation and coping strategies are best conceptualized in terms of flexibility in the broader literature, few ED studies have adopted this model. We review the current conceptual framework of emotion regulation and coping strategies used in ED research and present regulatory flexibility as an alternative approach to conceptualizing these strategies. The lack of research on regulatory flexibility among individuals with EDs limits our understanding of the role of emotion regulation and coping difficulties in ED risk and maintenance. Adopting a regulatory flexibility model of strategies in EDs may extend knowledge of the role of emotion regulation difficulties in the development and maintenance of EDs. We highlight the potential utility of investigating regulatory flexibility and present recommendations for future research on regulatory flexibility in EDs. PUBLIC SIGNIFICANCE STATEMENT: Research on emotion regulation and coping strategy usage in eating disorders often view regulatory strategies as inherently adaptive or maladaptive. However, recent studies support defining strategies in terms of flexibility. Adopting a regulatory flexibility model of strategies in eating disorders research may advance knowledge of the role of emotion regulation difficulties in the development and maintenance of eating disorders, ultimately enhancing prevention and treatment efforts.

PTSD symptoms as a potential mediator of associations between military sexual assault and disordered eating.

Despite increasing rates of sexual assault in the military and high rates of disordered eating and post-traumatic stress disorder (PTSD) among veterans, little is known about how these constructs are related. This study examined whether PTSD symptoms mediate the relation between military sexual assault and disordered eating among female veterans. United States female veterans (N = 98) completed self-report measures assessing military sexual assault, PTSD, and disordered eating. Results indicated that military sexual assault was associated with higher PTSD symptoms and disordered eating. PTSD symptoms did not mediate the relation between military sexual assault and overall levels of disordered eating. However, PTSD symptoms fully mediated the relation between military sexual assault and the Bulimia and Food Preoccupation subscale of the Eating Attitudes Test-26. Findings suggest that military sexual assault may contribute to the development of bulimia nervosa symptoms indirectly through PTSD symptoms. Thus, the findings do not support a global relationship between trauma and all facets of disordered eating, but demonstrate a relationship between PTSD and bulimia nervosa symptoms, with purging potentially functioning as an emotion regulation strategy. Future longitudinal studies are needed to establish temporal precedence of these associations.

Reducing eating disorder risk among male athletes: A randomized controlled trial investigating the male athlete body project.

OBJECTIVE: No study to date has investigated an intervention program for male athletes that targets eating disorder risk factors. The purpose of this study was to measure the effects of the Male Athlete Body Project (MABP), an adaptation of the Female Athlete Body Project on body dissatisfaction, drive for muscularity, body-ideal internalization, and muscle dysmorphia. METHOD: Participants were 79 male collegiate athletes who were randomized to the MABP (n = 39) or an assessment-only control condition (n = 40). All participants completed psychometrically validated measures at three time points: baseline, post-treatment (3 weeks after baseline for the control condition), and 1-month follow-up. RESULTS: Hierarchical Linear Modeling assessed differences between conditions across time. Interaction effects revealed that participation in the MABP improved satisfaction with specific body parts and reduced drive for muscularity and body-ideal internalization at post-treatment compared to a control group. Athletes in the MABP also reported increased body areas satisfaction and reductions in drive for muscularity at 1-month follow-up. Reductions in supplement use were observed at 1-month follow-up only. DISCUSSION: This study provides preliminary evidence of the efficacy of the MABP in reducing some eating disorder risk factors up to 1 month after the intervention; follow-up study considerations are discussed. CLINICAL TRIAL REGISTRATION NUMBER: NCT04077177 PUBLIC SIGNIFICANCE: This study highlights the importance of eating disorder and body image intervention efforts for male athletes. Findings suggest that male college athletes who attended a 3-session group intervention based on a well-established program for college women experienced an increase in satisfaction with specific body areas and a reduction in some eating disorder risk factors (e.g., drive for muscularity, supplement use, and body-ideal internalization) compared to a control group.

The moderating role of sleep duration on momentary relations between negative affect and loss-of-control eating in children and adolescents.

OBJECTIVE: Loss-of-control (LOC) eating is associated with eating disorders and obesity, and thus it is imperative to understand its momentary risk factors in order to improve intervention efforts. Negative affect has been proposed as a momentary risk factor for LOC eating, but the evidence for its effects in children and adolescents is mixed. Short sleep duration (which is very common in youth), may be one variable that moderates the relation between negative affect and subsequent LOC eating. As such, we aimed to examine the moderating role of within-person sleep duration on the momentary relations between negative affect and subsequent LOC eating. METHOD: We recruited children (N = 30) with overweight/obesity ages 8-14, who completed a 2-week ecological momentary assessment protocol assessing negative affect and LOC eating several times per day, while also wearing a sleep actigraphy device and completing sleep diaries. RESULTS: Consistent with hypotheses, within-person sleep duration moderated the next-day momentary relation between within-person negative affect and LOC eating, such that shorter sleep duration strengthened the positive relation between negative affect and loss-of-control eating. CONCLUSIONS: Results suggest that, in children and adolescents, fluctuations in sleep duration may influence susceptibility to losing control over eating after experiencing negative affect. Future research should further investigate other metrics of sleep disturbance as they relate to emotion regulation and LOC eating. Such research will set the stage for augmenting paediatric interventions to better target maintenance factors for LOC eating.

Overweight preoccupation is associated with eating pathology in male collegiate athletes with body dissatisfaction.

PURPOSE: This study examined specific aspects of body dissatisfaction and drive for muscularity as correlates of eating pathology and explored sport confidence as a moderator of these associations in male collegiate athletes. METHOD: Ninety-three male collegiate athletes who endorsed body dissatisfaction and were enrolled in a body dissatisfaction intervention study completed baseline measures of appearance orientation, appearance evaluation, overweight preoccupation, muscularity-oriented attitudes and behaviors, eating pathology symptoms, and sport confidence. RESULTS: There were significant associations between overweight preoccupation and cognitive restraint, purging, binge eating, and excessive exercise, appearance orientation and cognitive restraint, negative appearance evaluation and restricting, muscularity-oriented attitudes and binge eating, and muscularity-oriented behaviors and excessive exercise. Low-to-moderate sport confidence moderated the association between muscularity-oriented behaviors and purging. CONCLUSION: Findings highlight a need for interventions targeting drive for muscularity and body dissatisfaction, especially overweight preoccupation, in male collegiate athletes. Findings additionally suggest a need to further examine the utility of sport confidence in prevention and intervention programs targeting eating pathology in larger samples of male athletes. LEVEL OF EVIDENCE: V, Cross-sectional descriptive study.

Women of diverse sexual identities admit to eating disorder treatment with differential symptom severity but achieve similar clinical outcomes.

OBJECTIVE: Sexual minority (SM) women may be at increased risk for certain eating disorder (ED) symptoms and report distinct body image concerns compared to heterosexual women. However, it is unclear how such symptoms differ across sexual orientations in treatment-seeking women, or if there are differences in treatment outcomes. This study examined group differences in (1) ED symptomatology at admission in a disaggregated sample of SM and heterosexual women presenting for ED treatment and (2) treatment outcomes. METHODS: Adult women who admitted to higher levels of ED treatment across 48 locations of one treatment center between 2015 and 2018 completed self-report measures of ED symptomatology and quality of life (QOL) at admission and discharge. Participants identified their sexualities as heterosexual (n = 2,502, 80.2%), lesbian/gay (n = 134, 4.3%), bisexual (n = 270, 8.7%), "other" (n = 136, 4.4%), and unsure (n = 78, 2.5%). Objectives 1 and 2 were tested using one-way and repeated measures analyses of variance, respectively. RESULTS: Group differences at admission emerged between lesbian/gay and heterosexual, bisexual and heterosexual, and bisexual and "other"-identified women on preoccupation and restriction, fasting, self-induced vomiting, shape and weight concern, and QOL. Bisexual women, in particular, admitted with the highest severity and at younger ages compared to heterosexual women. Despite such differences, women across groups achieved similar treatment outcomes at discharge. DISCUSSION: Study findings underscore the importance of subgroup analyses of ED symptoms in SM women and have both clinical and research implications related to ED symptomatology in this population.

Momentary associations between positive affect dimensions and dysregulated eating during puberty in a diverse sample of youth with overweight/obesity.

OBJECTIVE: The link between dysregulated positive affect and binge-eating behavior in youth with obesity is poorly understood. In addition, it is unclear how putative associations differ across developmental periods of rapid biological and emotional change, such as puberty, and in racial and ethnic minority youth, who are more likely to be overweight but are underrepresented in the literature. METHOD: This study used a 2-week ecological momentary assessment protocol to examine independent and interactive effects of positive affect intensity/instability, and pubertal stage on two components of binge-eating behavior, loss of control eating (LOCE), and overeating. RESULTS: Participants were 38 youth with overweight/obesity (ages 8-14 years; 78% African American/Hispanic). Positive affect instability was calculated using probability of acute change (PAC), representing the likelihood of extreme affective changes, and mean squared successive difference (MSSD), representing the average change in affect over successive recordings. There were no main effects of positive affect intensity on LOCE or overeating, but positive affect instability was negatively associated with overeating severity using both MSSD (p = .005) and PAC metrics (p = .001). However, moderation analyses including interactions with pubertal status revealed more extreme changes in positive affect (i.e., higher PAC) were related to greater overeating (p = .001) and LOCE severity (p = .043) in mid-late pubertal youth but not in pre-early pubertal youth. DISCUSSION: Pubertal status may influence the association between disruptions in positive affect and dysregulated eating in youth, and positive affect instability may be important to consider in order to understand the emotional correlates of binge eating in youth with overweight/obesity.

The interactive effects of parental self-efficacy and child eating styles in relation to naturalistically-assessed craving, overeating, and loss of control eating.

OBJECTIVE: Parental factors have been linked to weight-related outcomes in children, though less is known regarding the role of parental self-efficacy (PSE) for promoting healthy dietary behaviors (HDBs). This study examined associations between PSE for promoting HDBs and child reports of craving, overeating, and loss of control eating in daily life. The interactive effects of PSE and child eating style (emotional eating, external eating, and restraint) were also explored. METHOD: Thirty-eight youth (ages 8-14; 55.3% female) with overweight/obesity and their parents completed the Dutch Eating Behavior Questionnaire for Children (DEBQ-C) and Parental Self-Efficacy for Healthy Dietary and Physical Activity Behaviors Scale, respectively. Youth completed ecological momentary assessment (EMA) to report craving, overeating, and loss of control eating. RESULTS: Generalized estimating equations indicated no consistent main effects of PSE on EMA outcomes, but PSE interacted with DEBQ-C child eating styles to predict each EMA outcome. Among children of parents with lower PSE, (a) higher emotional eating was associated with greater overeating and loss of control eating; (b) higher external eating was associated with greater craving; and (c) higher restraint was associated with greater loss of control eating and craving. Conversely, these associations were attenuated among children of parents with higher PSE. DISCUSSION: Together findings suggest the interplay of child characteristics and PSE regarding children's eating behaviors warrants future investigation in the context of eating and weight disorders. In particular, further research is needed to examine the directionality of effects and mechanisms underlying these associations.

Associations between naturalistically assessed physical activity patterns, affect, and eating in youth with overweight and obesity.

Insufficient physical activity (PA) and excessive stationary behavior (SB) are contributors to pediatric obesity, though antecedents and consequences of these behaviors in this population are relatively unknown. This pilot study examined affect, loss of control eating (LOCE), overeating, and hunger surrounding PA and SB in 17 youth with overweight/obesity. Participants completed a 14-day ecological momentary assessment (EMA) wearing accelerometers. At the momentary level, higher negative affect and lower positive affect predicted SB increases and PA decreases following EMA prompts; higher PA and lower SB also predicted increases in positive affect. Higher LOCE predicted SB increases and PA decreases, while increases in PA and decreases in SB predicted short-term increases in LOCE and overeating. At the individual level, higher SB and lower PA were related to lower positive affect and higher negative affect, LOCE, overeating, and hunger. Findings suggest affect is a relevant antecedent and consequence of PA/SB, and dysregulated eating may acutely impact PA/SB.

Naturalistic, multimethod exploratory study of sleep duration and quality as predictors of dysregulated eating in youth with overweight and obesity.

Although poor sleep has been found to adversely impact eating and weight regulation in youth, past research is limited by retrospective reporting and/or non-naturalistic designs. We investigated the feasibility of combining three momentary, ecologically valid approaches to assessing sleep and eating behavior, and associations between these constructs, among youth (aged 8-14y) with overweight/obesity (n = 40). Participants completed 14 overlapping days of actigraphy assessment and smartphone-based ecological momentary assessment (EMA) of eating behavior, of which 3 days also included computerized, self-guided 24-h dietary recall. Feasibility of completing measures concurrently was evaluated by generating frequencies of compliance. Associations between sleep indices and next-day eating behavior were examined via generalized estimating equations. Of 29 participants who provided EMA and 24-h recall data that aligned with previous night actigraphy data, both EMA and sleep data were available on an average of 8.6 out of 14 possible days, and both 24-h recall and sleep data on an average of 2.7 out of 3 possible days. Each additional hour of sleep was associated with consuming fewer calories from solid fats, alcohol, and added sugars (b = 0.70; p = .04). Combining naturalistic, momentary assessments of sleep and eating behavior appears to be acceptable in youth. Larger experimental studies are needed to further understand associations between sleep parameters and eating behavior.

Threat appraisal partially mediates the relation between neuroticism and bulimic symptoms.

Several studies support an association between neuroticism and bulimic symptoms; however, few studies have focused on how neuroticism exerts its influence. The purpose of this study was to extend the literature by investigating threat appraisal as a potential mediator of the relation between neuroticism and bulimic symptoms. One hundred and twenty women completed self-report measures of trait neuroticism, threat appraisal, and bulimic symptoms. Approximately half of the sample reported moderate or high levels of bulimic symptoms. Bootstrapping analyses revealed that neuroticism and threat appraisal were both positive predictors of bulimic symptoms. Further, threat appraisal partially mediated the association between neuroticism and bulimic symptoms. The findings suggest that women high in neuroticism may be vulnerable to experiencing bulimic symptoms, particularly during periods of heightened stress. These women may perceive bulimic behavior to be more effective in alleviating negative stressful emotions compared to more adaptive coping strategies. Based on the findings, women diagnosed with bulimia nervosa with high levels of neuroticism may benefit from interventions that specifically target threat appraisals to facilitate their ability to effectively adapt to stress.

Disturbance of gut satiety peptide in purging disorder.

OBJECTIVE: Little is known about biological factors that contribute to purging after normal amounts of food-the central feature of purging disorder (PD). This study comes from a series of nested studies examining ingestive behaviors in bulimic syndromes and specifically evaluated the satiety peptide YY (PYY) and the hunger peptide ghrelin in women with PD (n = 25), bulimia nervosa-purging (BNp) (n = 26), and controls (n = 26). Based on distinct subjective responses to a fixed meal in PD (Keel, Wolfe, Liddle, DeYoung, & Jimerson, ), we tested whether postprandial PYY response was significantly greater and ghrelin levels significantly lower in women with PD compared to controls and women with BNp. METHOD: Participants completed structured clinical interviews, self-report questionnaires, and laboratory assessments of gut peptide and subjective responses to a fixed meal. RESULTS: Women with PD demonstrated a significantly greater postprandial PYY response compared to women with BNp and controls, who did not differ significantly. PD women also endorsed significantly greater gastrointestinal distress, and PYY predicted gastrointestinal intestinal distress. Ghrelin levels were significantly greater in PD and BNp compared to controls, but did not differ significantly between eating disorders. Women with BNp endorsed significantly greater postprandial hunger, and ghrelin predicted hunger. DISCUSSION: PD is associated with a unique disturbance in PYY response. Findings contribute to growing evidence of physiological distinctions between PD and BNp. Future research should examine whether these distinctions account for differences in clinical presentation as this could inform the development of specific interventions for patients with PD.

Ecological momentary assessment of maladaptive eating in children and adolescents with overweight or obesity.

OBJECTIVES: Contextual factors related to maladaptive eating behavior in youth with overweight/obesity are poorly understood. This pilot study sought to elucidate immediate internal and external cues related to perceptions of overeating and loss of control (LOC) over eating in a heterogeneous sample of children and adolescents with overweight/obesity assessed in their natural environments. METHOD: Community-based youth [N = 40; 55% female (n = 22)], aged 8-14 y (M age = 11.2 ± 1.9 y), with overweight/obesity (M z-BMI = 2.07 ± 0.49) reported on all eating episodes and their physiological, environmental, affective, and interpersonal antecedents and correlates via ecological momentary assessment over a 2-week period. Generalized estimating equations were used to assess the relationship between contextual variables and degree of overeating and LOC. RESULTS: Eating occasions involving greater food hedonics (i.e., perceived palatability of food being consumed) were associated with greater LOC severity (within-subjects effect: B = 0.01, p = .015), although youth with lower overall levels of food hedonics reported higher LOC severity ratings on average (between-subjects effect: B = -0.04, p = .005). Youth reporting higher overall cravings reported higher average ratings of LOC severity (between-subjects effect: B = 0.20, p = .001). Finally, youth reporting greater overall influence of others on eating behavior evidenced greater average levels of overeating severity (between-subjects effect: B = 0.17, p < .001). DISCUSSION: Eating-related factors appear to be most strongly associated with LOC severity, while environmental factors were most associated with overeating severity. Interventions targeting maladaptive eating in youth with overweight/obesity may benefit from helping youth incorporate palatable foods and satisfy cravings in a planned and controlled manner, and enhancing awareness of social-contextual effects on eating.

Satiation deficits and binge eating: Probing differences between bulimia nervosa and purging disorder using an ad lib test meal.

Purging disorder (PD) has been included as a named condition within the DSM-5 category of Other Specified Feeding or Eating Disorder and differs from bulimia nervosa (BN) in the absence of binge-eating episodes. The current study evaluated satiation through behavioral and self-report measures to understand how this construct may explain distinct symptom presentations for bulimia nervosa (BN) and purging disorder (PD). Women (N = 119) were recruited from the community if they met DSM-5 criteria for BN (n = 57), PD (n = 31), or were free of eating pathology (n = 31 controls). Participants completed structured clinical interviews and questionnaires and an ad lib test meal during which they provided reports of subjective states. Significant group differences were found on self-reported symptoms, ad lib test meal intake, and subjective responses to food intake between individuals with eating disorders and controls and between BN and PD. Further, ad lib intake was associated with self-reported frequency and size of binge episodes. In a multivariable model, the amount of food consumed during binges as reported during clinical interviews predicted amount of food consumed during the ad lib test meal, controlling for other binge-related variables. Satiation deficits distinguish BN from PD and appear to be specifically linked to the size of binge episodes. Future work should expand exploration of physiological bases of these differences to contribute to novel interventions.

Weight suppression and bulimic syndrome maintenance: Preliminary findings for the mediating role of leptin.

OBJECTIVE: Longitudinal studies support a prospective relationship between weight suppression (WS) and bulimic syndrome (BN-S) maintenance. Although biobehavioral mechanisms have been proposed to explain this link, such mechanisms have yet to be identified. Given that weight loss would reduce leptin levels which may influence eating, this study examined whether reduced leptin levels mediate the link between greater WS and longer illness duration. METHOD: Women (N = 53), ages 18-45 years, were recruited from the community if they met criteria for a BN-S, including either DSM-5 bulimia nervosa (BN; n = 33) or purging disorder (PD: n = 20), and fell within a healthy weight range (18.5-26.5 kg/m2 ). Participants completed clinical assessments and provided blood samples to measure circulating leptin. RESULTS: Significant associations were found among greater WS, lower leptin concentrations, and longer duration of illness. Mediation analyses using bootstrapping procedures indicated all paths were significant and that leptin mediated the link between WS and illness duration. An alternative model in which longer illness duration contributed to leptin, via greater WS, was not supported. DISCUSSION: Longitudinal research is needed to support temporal associations and explore behavioral mechanisms linking leptin to illness trajectory.

Incremental validity of the episode size criterion in binge-eating definitions: An examination in women with purging syndromes.

OBJECTIVE: Of the two primary features of binge eating, loss of control (LOC) eating is well validated while the role of eating episode size is less clear. Given the ICD-11 proposal to eliminate episode size from the binge-eating definition, the present study examined the incremental validity of the size criterion, controlling for LOC. METHOD: Interview and questionnaire data come from four studies of 243 women with bulimia nervosa (n = 141) or purging disorder (n = 102). Hierarchical linear regression tested if the largest reported episode size, coded in kilocalories, explained additional variance in eating disorder features, psychopathology, personality traits, and impairment, holding constant LOC eating frequency, age, and body mass index (BMI). Analyses also tested if episode size moderated the association between LOC eating and these variables. RESULTS: Holding LOC constant, episode size explained significant variance in disinhibition, trait anxiety, and eating disorder-related impairment. Episode size moderated the association of LOC eating with purging frequency and depressive symptoms, such that in the presence of larger eating episodes, LOC eating was more closely associated with these features. Neither episode size nor its interaction with LOC explained additional variance in BMI, hunger, restraint, shape concerns, state anxiety, negative urgency, or global functioning. DISCUSSION: Taken together, results support the incremental validity of the size criterion, in addition to and in combination with LOC eating, for defining binge-eating episodes in purging syndromes. Future research should examine the predictive validity of episode size in both purging and nonpurging eating disorders (e.g., binge eating disorder) to inform nosological schemes. © 2016 Wiley Periodicals, Inc. (Int J Eat Disord 2016; 49:651-662).