Dysphoric mood may explain the relation between sleep reactivity and binge eating but not purging.

Objective: This study investigated whether sleep reactivity (i.e., a propensity to experience sleep disturbances when stressed) relates to eating disorder behavioral symptoms indirectly through dysphoric mood in a sample of college students. Participants: One hundred and ninety-eight college students (51.5% female). Methods: Participants completed self-report measures of dysphoric mood, eating disorder behavioral symptoms, and sleep reactivity. Results: Higher sleep reactivity was associated with greater binge-eating symptoms indirectly through higher dysphoric mood. Higher sleep reactivity was associated with greater purging symptoms; however, this association was not explained by dysphoric mood. Conclusions: Findings support the relevance of sleep reactivity to binge eating and purging and suggest that sleep reactivity relates to binge-eating symptoms indirectly through dysphoric mood. If replicated in prospective data, targeting stress-induced sleep and mood disturbances in college students may reduce risk for binge eating.

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.

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.

Accelerometer-Based Physical Activity and Shape and Weight Concerns Among Youth With Overweight and Obesity: A Pilot Exploratory Ecological Momentary Assessment Study.

Background: A bidirectional association between shape and weight concerns (SWC) and physical activity (PA) has been previously documented. This relationship may be particularly salient among youth with overweight/obesity, given that social marginalization of larger bodies has been associated with elevated SWC and barriers to PA. This pilot study explores reciprocal relationships between momentary SWC and accelerometer-assessed PA behavior. Methods: Youth with overweight/obesity (N = 17) participated in a 14-day ecological momentary assessment protocol, during which they were prompted to respond to questions about SWC several times per day. They also continuously wore Actiwatch 2 accelerometers to capture light and moderate-to-vigorous PA behavior. Results: Hierarchical linear modeling revealed a unidirectional association between SWC and PA, whereby after engaging in a higher duration of PA, participants reported lower SWC. SWC did not predict subsequent PA. Conclusion: The findings support a negative temporal relationship between PA and SWC. While further work is needed to replicate and extend these preliminary findings, they may suggest that PA acutely benefits SWC among youth with overweight and obesity.

Sleep reactivity is associated with social anxiety and disordered-eating behaviors in college students.

Objective: Investigate whether sleep reactivity was associated with social anxiety and disordered-eating behaviors in a college population. Participants: One hundred ninety-eight college-age men and women. Methods: Participants completed self-report measures of social anxiety, disordered-eating behaviors and sleep reactivity. Results: Sleep reactivity was associated with greater dietary restriction and purging, controlling for social anxiety but it was not associated with binge eating. Sleep reactivity was associated with elevated symptoms of social anxiety, controlling for disordered-eating behaviors. Conclusions: The results suggest that sleep reactivity represents a shared correlate of disordered-eating behaviors and social anxiety that may partially explain their co-occurrence. Interventions to help college students high in sleep reactivity effectively manage stress and regulate their sleep may aid in the prevention and treatment of social anxiety and disordered-eating behaviors.

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.

Body dissatisfaction among ethnic subgroups of Latin women: An examination of acculturative stress and ethnic identity.

This study investigated (1) ethnic group differences in body dissatisfaction (BD) among specific Latina subgroups, (2) acculturative stress as a mediator between ethnic group and BD, and (3) ethnic identification as a moderator between 3a) ethnic group and BD and 3b) acculturative stress and BD. Mexican (n = 30), Puerto Rican (n = 31), Cuban (n = 29), and non-Hispanic, White (n = 30) women in the US completed self-report questionnaires. Group comparisons indicated Mexicans reported greater BD compared to Whites, while Puerto Ricans and Cubans did not differ from Whites. A significant indirect effect indicated that acculturative stress mediated the association between ethnic group and BD. Acculturative stress predicted BD at low and average levels of ethnic identification. Additionally, there were significant differences comparing Cubans to Mexicans and Puerto Ricans, which were dependent on ethnic identification. Thus, higher ethnic identification may serve as a protective factor for Cubans. Findings support separating subgroups of Latinas and that higher ethnic identification may protect against the development of BD in Latinas experiencing acculturative stress. Assessments and interventions should address acculturative stress since higher levels were associated with higher levels of BD, and the combination of ethnic group, acculturative stress, and ethnic identification may help explain differences in BD among Latinas.

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.

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.

Gender differences in the relation between interpersonal stress and momentary shape and weight concerns in youth with overweight/obesity.

The purpose of this study was to examine relations between interpersonal stress and momentary shape and weight concerns among pre-adolescent and early adolescent boys and girls with overweight/obesity, using ecological momentary assessment (EMA). We also aimed to determine whether interpersonal stress was differentially related to shape/weight concerns in boys versus girls. Forty youth, ages 8-14 years (53% female), with overweight or obesity reported their state-level shape/weight concerns and negative affect and their recent interpersonal stress (i.e., stress experienced since the last EMA assessment) multiple times a day, for two weeks. Results indicated that interpersonal stress predicted shape/weight concerns in girls but was not related to shape/weight concerns in boys. At the between-person level, higher overall feelings of loneliness and social rejection and a higher overall desire for more friends predicted higher average levels of shape/weight concerns. At the within-person level, higher momentary ratings of loneliness, social rejection, and desire for more friends predicted lower shape/weight concerns. These data suggest that the tendency to experience interpersonal stress may be more detrimental to body satisfaction for girls with overweight/obesity than for boys with overweight/obesity. Interventions that focus on reducing interpersonal stress may be effective in ameliorating shape/weight concerns in girls with overweight/obesity.

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.

Nutrition knowledge moderates the association between perfectionism and shape/weight concerns.

Perfectionistic traits have been associated with stronger weight and diet concerns. Maladaptive perfectionism is tied to critical evaluation tendencies such as excessive concern about making mistakes, increasing one's risk for eating disorder pathology. Knowledge about healthy diet and nutrition may be one factor influencing associations between perfectionistic tendencies, as individuals with eating disorders may be more attuned to sources of nutrients. The current study examined whether nutrition knowledge moderates the association between one facet of perfectionism, concern over mistakes, and shape/weight concerns and the association between concern over mistakes and global eating pathology. College women (N = 122) completed questionnaires on disordered eating attitudes, nutrition knowledge, and perfectionism. Concern over mistakes was positively related to shape/weight concerns and global eating pathology. Nutrition knowledge significantly moderated the association between concerns over mistakes and shape/weight concerns, such that the association was stronger among those with higher levels of nutrition knowledge. Furthermore, nutrition knowledge displayed trend-level significance for the moderation of the association between concern over mistakes and global eating pathology. College women displaying high levels of concern over mistakes who are more informed about nutrition knowledge may be more vulnerable to developing concerns about body shape/weight and eating disorder pathology.

Emotion regulation flexibility and disordered eating.

Research suggests that individuals with eating disorders use more putatively maladaptive emotion regulation strategies and fewer putatively adaptive strategies. However, there is growing theoretical and empirical support for the notion that the efficacy of emotion regulation strategies varies across situations. Thus, successful emotion regulation is characterized by the ability to flexibly choose between emotion regulation strategies in order to fit one's situational needs. Despite growing support for this conceptualization of successful emotion regulation, no research has investigated it in relation to disordered eating. Using the emotion regulation choice paradigm, this study investigated the association between emotion regulation flexibility and disordered eating. Women (N = 50) completed self-report questionnaires and a laboratory-based emotion regulation choice task to assess emotion regulation flexibility. Results indicated that lower emotion regulation flexibility was associated with more frequent purging and excessive exercise. Emotion regulation flexibility was not significantly associated with binge eating or overall eating disorder psychopathology. These findings suggest that individuals who engage in unhealthy compensatory behaviors exhibit reduced emotion regulation flexibility. If replicated in clinical samples, treatment for eating disorders characterized by compensatory behaviors may benefit from incorporating additional strategies to help people utilize emotion regulation strategies in a flexible, situationally appropriate manner.

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.

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.

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.

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).

Affect regulation and purging: An ecological momentary assessment study in purging disorder.

Research suggests that affect may play an important role in the propensity to purge among women with purging disorder (PD). However, prior work has been constrained to cross-sectional or laboratory designs, which impact temporal interpretations and ecological validity. This study examined negative affect (NA) and positive affect (PA) in triggering and maintaining purging in PD using ecological momentary assessment. Women with PD (N = 24) made multiple daily ratings of affect and behavior for 2 weeks. Multilevel models examined associations between affect and purging at different levels of analysis, including a novel analytic approach to address the specificity of changes in affect relative to purging behavior by comparing trajectories of change on purge versus nonpurge days. For trajectories of affect over time, NA increased before purging and decreased following purging on purge days; however, only the decrease in NA following purging was significantly different from the trajectory of NA on nonpurge days. Conversely, PA failed to increase before purging on purge days compared with a matched time-point on nonpurge days. These findings suggest unique roles of PA in triggering and NA in maintaining purging in PD and support models in which purging functions to regulate affect. For comparisons of ratings before and after purging, NA increased and PA decreased after purging, highlighting how different analytic strategies produce different findings requiring integration into affect regulation models. These data provide insight into why women with PD purge after consuming normal amounts of food, a crucial first step for developing effective interventions.