Relationships Between Dietary Intake and Weight-Related Experiential Avoidance Following Behavioral Weight-Loss Treatment.

BACKGROUND: Interventions targeting weight-related experiential avoidance (EA) and disinhibited eating (DE) may also improve diet quality. Participants with overweight/obesity and DE who recently completed a behavioral weight-loss program were randomized to receive acceptance and commitment therapy or continued behavioral weight-loss treatment. In this secondary analysis, we explored (1) change in diet quality from baseline to 6-month follow-up (FU) and (2) whether weight-related EA at baseline and (3) change in weight-related EA during treatment were related to change in diet quality from baseline to FU. METHOD: Veterans (N = 68) completed food frequency questionnaires at baseline and FU, which were used to generate diet quality scores on the healthy eating index-15 (HEI-15). Weight-related EA was assessed using the Acceptance and Action Questionnaire for Weight-Related Difficulties-Revised (AAQW-R) at baseline, post-treatment, and FU. Aims were examined with mixed ANOVA analyses. RESULTS: Across both treatment groups, HEI-15 scores declined from baseline to FU. Women's HEI-15 decreased by about 5 times that of men. Baseline AAWQ-R was negatively associated with change in HEI-15. Neither AAWQ-R at post-treatment nor change in AAQW-R from baseline to post-treatment was significantly associated with change in HEI-15 at FU. CONCLUSIONS: Greater weight-related EA at baseline was associated with lower diet quality at FU, but change in weight-related EA during treatment did not predict change in diet quality at FU. Interventions targeting DE and weight-loss may require specific components to improve and sustain healthy dietary intake in Veterans with obesity and DE.

Physical discomfort intolerance as a predictor of weight loss and physical activity in a lifestyle modification program.

This study examined physical discomfort intolerance (DI) as a baseline predictor of weight loss and physical activity outcomes, and assessed whether changes in DI during the initial phase of weight loss prospectively predicted long-term treatment outcomes among adults enrolled in a group-based lifestyle modification program for obesity. DI was measured at baseline and 6 months, and weight and accelerometer-measured physical activity were assessed at baseline, 6 months, and 12 months. Baseline DI was not related to weight loss or physical activity at either timepoint. Change in DI during the first 6 months of treatment was not related to concurrent (i.e., 6-month) weight loss and physical activity, but was significantly predictive of weight loss and physical activity at 12 months. Assessing early changes in DI may help to identify individuals at risk for suboptimal outcomes. Future research should evaluate behavioral weight loss interventions designed to target DI.

Physical Activity Intentions and Behavior Mediate Treatment Response in an Acceptance-Based Weight Loss Intervention.

BACKGROUND: Acceptance-based treatment (ABT) for weight loss has shown promise for improving outcomes relative to standard behavioral treatment (SBT). One way in which ABT may improve outcomes is through increasing physical activity (PA) intentions and behavior but little research has examined these as mediators of ABT on weight change. PURPOSE: This study sought to examine ABT's effects on intentions for PA and several objectively measured PA variables during treatment and analyze PA intentions and behaviors as mediators of ABT's effect on weight loss. METHODS: Participants (N = 189) with overweight/obesity randomized to 1 year of either ABT or SBT completed ecological momentary assessment of PA intentions, accelerometer-based PA assessment, and had weight measured at baseline, mid-treatment, and end of treatment. RESULTS: ABT had a significantly higher increase than SBT in PA intention minutes at mid-treatment and end of treatment (p < 0.001), and both groups had nonlinear increases in moderate-to-vigorous physical activity (MVPA) that were not significantly different. Sequential mediation models found that ABT's effect on weight loss was partially mediated by higher PA intention minutes at mid-treatment leading to increased MVPA minutes per week. Increased MVPA minutes were obtained by participants increasing the number of days with MVPA bouts. CONCLUSIONS: ABT's effect on weight loss throughout treatment resulted, in part, from participants increasing their intentions for PA. Controlling for group, higher PA intentions were associated with more PA obtained through more days with exercise.

Self-report versus objective measurement of weight history: implications for pre-treatment weight gain.

There is increasing concern that patients gain considerable weight in the year prior to treatment and that outcomes may not reflect true treatment losses. To date, we know little about the accuracy of self-reported weight change prior to treatment. To investigate weight gain, and accuracy of self-reported recent weight history, Veterans (n = 126) reported their current weight and one-year weight history prior to entering treatment. These weights were compared to electronic medical record weights. Patients gained an average of 2.03 kg (4.5 lbs) in the year prior to treatment. Self-report and objective weight assessments showed high concurrent validity at the group level. However, standard deviations for the absolute difference scores revealed high individual variability in historical reporting, suggesting that weight loss seeking patients are inaccurate reporters of recent weight. Our findings have implications for the emerging area of pre-treatment weight gain research and processes for clinical care.

Improvement in 6-min Walk Test Distance Following Treatment for Behavioral Weight Loss and Disinhibited Eating: an Exploratory Secondary Analysis.

BACKGROUND: Poor functional exercise capacity is common among those with obesity; however, objective measures of exercise capacity are rarely examined in behavioral treatments targeting obese individuals. We examined whether a 4-week acceptance and commitment therapy (ACT) intervention for disinhibited eating or a behavioral weight loss (BWL) intervention improved exercise capacity and explored demographic and disinhibited eating variables related to exercise capacity. METHODS: Veterans (n = 61), randomized to receive ACT or BWL, completed an assessment of exercise capacity via the 6-min walk test (6MWT) at baseline and 6-month follow-up. Measures of disinhibited eating patterns and body mass index (BMI), at baseline and post-treatment, were also collected. Change in 6MWT distance and treatment group differences were examined using mixed ANOVAs. Characteristics related to baseline 6MWT and predictors of improvement in 6MWT at 6 months were examined with hierarchical multiple regression. RESULTS: There were overall significant improvements on the 6MWT from baseline to 6-month follow-up (F(1,59) = 11.14, p = .001, ηp2 = .159) but no differences between the ACT and BWL groups. Baseline BMI (ß = - .33, p = .005) was the only variable related to baseline 6MWT. Improvements on the 6MWT were related to younger age (ß = - .41, p = 0.001), female gender (ß = .36, p = .001), and treatment-related increases in dietary restraint behaviors (ß = .42, p = .001). CONCLUSIONS: Functional exercise capacity improved among participants completing behavioral interventions for weight and disinhibited eating. Improvements in dietary behavior regulatory skills may have generalized to improved regulation in other behavioral domains associated with exercise capacity.

Dietary restraint and weight loss in relation to disinhibited eating in obese Veterans following a behavioral weight loss intervention.

Ability to restrain one's dietary intake is a necessary skill for weight loss. However, dietary restraint has been shown to paradoxically increase disinhibited eating in certain populations, thereby negatively impacting weight loss and leading to worse overall health outcomes. The aim of this study was to address gaps in the literature regarding the relationships between separate facets of dietary restraint (intention; behavior) with weight loss and various types of disinhibited eating (binge eating, external eating, emotional eating) in overweight and obese adults who recently completed a weight loss intervention. A sample of mostly male Veterans with overweight and obesity (N = 88) self-reported their dietary restraint intention, restraint behavior, and current disinhibited eating following completion of an 8-week behavioral weight loss treatment. Greater dietary restraint intention was related to greater dietary restraint behavior, p < .05. Greater dietary restraint behavior was significantly related to greater recent weight loss, p < .05, while restraint intention was not, p > .05. Greater dietary restraint intention was related to greater current binge eating and external eating, while greater self-reported restraint behavior was related to less binge eating, p < .05. Thus, dietary restraint behavior appears to be adaptive for this population, whereas rigid dietary restraint intention may increase risk for disinhibited eating. To decrease disinhibited eating and improve weight loss outcomes in Veterans, interventions might specifically address rigid rule-following associated with abandonment of weight loss goals and help Veterans develop specific yet flexible eating plans. Future research should examine whether dietary restraint intention and behavior differentially predict disinhibited eating and weight loss outcomes prospectively.

Just-in-time adaptive interventions: A novel approach for enhancing skill utilization and acquisition in cognitive behavioral therapy for eating disorders.

OBJECTIVE: The most widely researched treatment for bulimia nervosa (BN) and binge-eating disorder (BED) is cognitive behavioral therapy (CBT), a present-focused, active, skill-oriented treatment. However, despite the success of CBT, many patients fail to achieve sufficient rates of skill utilization (i.e., the frequency with which a patient practices or uses therapeutic skills) or adequate skill acquisition (i.e., the ability to successfully perform a skill learned in treatment) by the end of treatment and outcomes suffer as a result. One method for improving skill acquisition and utilization in patients with BN or BED could be the augmentation of in-person treatment with just-in-time adaptive interventions (JITAIs), which use smartphone technology to deliver real-time interventions during app-identified moments of need. The current article discusses how novel JITAI systems that utilize machine learning or other predictive algorithms could be used to detect momentary risk for eating disordered behavior and provide tailored interventions to enhance outcomes. We will consider technologies that may help reduce patient burden and suggest avenues for future research on developing acceptable and effective JITAIs that can be used as an adjunct to CBT protocols.

Pain and modifiable risk factors among weight loss seeking Veterans with overweight.

OBJECTIVE: Overweight/obesity and chronic pain frequently co-occur and demonstrate a bidirectional relationship. Modifiable risk factors, such as eating behaviors and mental health symptoms, may be important to understand this relationship and improve interventions in Veterans. DESIGN: Cross-sectional. SETTING: Veterans Health Administration Medical Center outpatient clinic. SUBJECTS: The sample of Veterans (N = 126) was mostly male (89.7%), White (76%), and non-Hispanic (94%) with average age of 61.9 years (SD = 8.5) and average body mass index (BMI) of 38.5 (SD = 7.5). METHODS: Veterans referred for weight loss treatment (MOVE!) at VA Connecticut completed self-report questionnaires, and electronic medical records were reviewed. RESULTS: Mean self-reported pain rating was 4.5 out of 10 (SD = 2.3). Moderate to severe pain was endorsed by 60% of the sample. Veterans with higher pain intensity and interference reported higher global eating disorder symptoms, emotional overeating, night eating, insomnia severity, and mental health symptoms (all p's < 0.01). However, pain intensity and interference were not associated with BMI. CONCLUSIONS: For Veterans seeking behavioral weight loss treatment, higher pain intensity and interference were associated with more severe eating disorder, sleep, and mental health symptoms. A better description of the clinical characteristics of Veterans with pain who participate in MOVE! highlights their unique needs and may improve treatments to address pain in the context of weight loss treatment.

Walking a mile in another's shoes: The impact of wearing an Age Suit.

The "Age Suit" described in this article was developed to enable future designers, business leaders, and engineers to experience navigating the world as many older adults must. Tools such as this Age Suit offer the opportunity to "walk a mile" in another's shoes to develop empathy that can result in better design of spaces, goods, and services to meet the needs of a rapidly growing older population. This work first examined, through a series of clinical tests, whether younger adults' physical capacities were reduced in a direction consistent with aging by wearing a suit developed by the MIT AgeLab. An experiential learning task was then completed with the suit to understand its impact on completion of an instrumental activity of daily living. Results showed that younger adults wearing the suit experienced changes in task performance consistent with expected changes associated with aging. Participants' self-reports from the experiential learning task indicated that they were able to empathize with older adults regarding some issues they face while completing a grocery shopping task. Future research with the suit should involve a wider range of individuals from the population and examine what effect participants' levels of fitness have on the experience of wearing the suit.

Familial Contributions to Self-Reported Sleep and Pain in Female Twins.

OBJECTIVE: The relationship between sleep quality and pain has been studied in populations with chronic pain and in nonclinical populations using experimental paradigms. Little is known about the familial contributions to this relationship. This study examines self-reported sleep quality and pain in a nonclinical sample and to explore familial (i.e., shared genetic and common family environment) confounding in those relationships. DESIGN: Cross-sectional. SUBJECTS: Ninety nine community-based female twin pairs (N = 198) with a mean age of 29 years; 72% monozygotic. METHODS: The short form McGill Pain Questionnaire (McGill), a visual analog scale (VAS), a body map, and the Pittsburgh Sleep Quality Index (PSQI) measured self-reported pain and sleep quality. Mixed model regression adjusted for age was used to examine relationships between the pain indices and PSQI in overall and within-pair models. RESULTS: Higher PSQI total scores were significantly associated with higher scores across the McGill sensory (B = 0.37, p < 0.001), affective (B = 0.16, p < 0.001), total scores (B = 0.54, p < 0.001), the VAS (B = 2.41, p < 0.001), and number of sites with any pain on the body map (B = 0.42, p = 0.001). All of these associations were diminished and rendered nonsignificant in within-pair analyses that accounted for genetic and familial factors (all p's ≥ 0.01; Bonferroni α = 0.01). CONCLUSIONS: These findings support an association between poor sleep quality and pain and suggest that this relationship may be confounded by shared genetic and environmental factors, which could elucidate biological mechanisms that underlie the development and maintenance of pain and sleep problems.

Hookah Use Predicts Cigarette Smoking Progression Among College Smokers.

INTRODUCTION: Hookah use is increasingly common among U.S. college students, but little is known regarding the relationship between hookah and cigarette use. The purpose of this study was to test the hypothesis that the added nicotine exposure from hookah use may accelerate the uptake of cigarettes. METHODS: An ethnically diverse sample of college students (n = 256; 43% female) who had smoked cigarettes in the past month completed 2 in-person interviews over 6 months. This study was a secondary analysis of data collected for a longitudinal study of young adult cigarette smoking patterns. Analyses examined 6-month changes in past 30 day cigarettes smoked and number of days smoking, controlling for age, nicotine dependence, marijuana use, and the respective baseline variable for each outcome. RESULTS: Current hookah use (any use in past 30 days) was endorsed by 34% of participants at baseline, while 94% reported lifetime use. Change in past 30 day number of cigarettes (p = .043) and number of smoking days (p = .040) differed significantly between those who did or did not report recent hookah use at baseline. Hookah users reported a greater number of cigarettes smoked at the 6-month follow-up, while nonusers decreased their smoking quantity. For number of smoking days in the past 30, hookah users reported a smaller decrease than nonusers. CONCLUSIONS: Recent hookah use predicted increased cigarette smoking over 6 months in a college sample. These are the first prospective data demonstrating this relationship, indicating the value of developing strategies to prevent hookah use among college students.

Mindfulness-based interventions for binge eating: a systematic review and meta-analysis.

Mindfulness-based interventions are increasingly used to treat binge eating. The effects of these interventions have not been reviewed comprehensively. This systematic review and meta-analysis sought to summarize the literature on mindfulness-based interventions and determine their impact on binge eating behavior. PubMED, Web of Science, and PsycINFO were searched using keywords binge eating, overeating, objective bulimic episodes, acceptance and commitment therapy, dialectical behavior therapy, mindfulness, meditation, mindful eating. Of 151 records screened, 19 studies met inclusion criteria. Most studies showed effects of large magnitude. Results of random effects meta-analyses supported large or medium-large effects of these interventions on binge eating (within-group random effects mean Hedge's g = -1.12, 95 % CI -1.67, -0.80, k = 18; between-group mean Hedge's g = -0.70, 95 % CI -1.16, -0.24, k = 7). However, there was high statistical heterogeneity among the studies (within-group I(2) = 93 %; between-group I(2) = 90 %). Limitations and future research directions are discussed.

Salivary cortisol and cold pain sensitivity in female twins.

BACKGROUND: There is a dearth of knowledge about the link between cortisol and pain sensitivity. PURPOSE: We examined the association of salivary cortisol with indices of cold pain sensitivity in 198 female twins and explored the role of familial confounding. METHODS: Three-day saliva samples were collected for cortisol levels and a cold pressor test was used to collect pain ratings and time to threshold and tolerance. Linear regression modeling with generalized estimating equations examined the overall and within-pair associations. RESULTS: Lower diurnal variation of cortisol was associated with higher pain ratings at threshold (p = 0.02) and tolerance (p < 0.01). The relationship of diurnal variation with pain ratings at threshold and tolerance was minimally influenced by familial factors (i.e., genetics and common environment). CONCLUSIONS: Understanding the genetic and non-genetic mechanisms underlying the link between HPA axis dysregulation and pain sensitivity may help to prevent chronic pain development and maintenance.

Pain sensitivity in posttraumatic stress disorder and other anxiety disorders: a preliminary case control study.

BACKGROUND: Despite substantial research on the comorbidity of anxiety disorders including posttraumatic stress disorder (PTSD) and chronic pain, little is known about the mechanisms underlying these conditions that might be potentially similar. Evoked pain sensitivity is one factor that has been associated with several pain conditions which might also have relevance to anxiety disorders and PTSD. The aim of this preliminary study was to examine evoked pain sensitivity in PTSD compared to other anxiety disorders and in control participants. METHOD: The study used a cross-sectional case-control design in which participants completed a battery of questionnaires and structured interview and underwent cold pressor testing. RESULTS: Of 61 total participants, those in the PTSD (n =16) and other anxiety groups (n =12) endorsed significantly higher levels of psychological symptoms and poorer health functioning than control participants (n =33). The linear trend across baseline, threshold, and tolerance pain ratings from the cold pressor task significantly differed between participants with PTSD and the other anxiety and control groups suggesting lower pain sensitivity to a standardized stimulus of pain in individuals with PTSD. CONCLUSIONS: These findings are similar to some of the prior research and suggest that individuals with PTSD may exhibit lower cold pain sensitivity compared to those with other anxiety disorders. There is a need for future research to determine explanatory mechanisms.

Posttraumatic stress disorder and health: a preliminary study of group differences in health and health behaviors.

BACKGROUND: Individuals with posttraumatic stress disorder (PTSD) are more likely to undertake harmful health behaviors like substance use. Less is known about the association of PTSD with healthful behaviors such as healthy diet and exercise. The purpose of this study was to examine differences across physical health indicators and health behaviors in individuals with and without PTSD. METHODS: A cross-sectional, case-control study of health indicators and self-reported health behaviors in a community and military veteran sample was used. RESULTS: Based on a structured psychiatric interview, 25 participants had PTSD, and the remaining 55 without PTSD served as the comparison group. Participants were 40 years old on average and 45% were female. Multivariate analysis of variance analyses revealed that participants with PTSD had significantly higher body mass index (p = 0.004), had more alcohol use (p = 0.007), and reported fewer minutes of vigorous exercise (p = 0.020) than those without PTSD. Chi-square analysis of diet content and eating behavior constructs found that individuals with PTSD ate fewer fruits (p = 0.035) and had more guilt after overeating (p = 0.006). CONCLUSIONS: These findings replicate prior research on the link between PTSD and negative health outcomes and engagement in harmful health behaviors and highlight the need for further examination of the association between PTSD and other health behaviors like diet content, eating behaviors, and exercise.

The Well-Being of Peer Supporters in a Pandemic: A Mixed-Methods Study.

BACKGROUND: Peer support is an effective, well-received approach to caring for health care professionals who face stress, challenges, and reduced well-being. Peer supporters may be at risk for emotional exhaustion and secondary traumatic stress due to their primary roles and involvement as peer supporters during the COVID-19 pandemic. METHODS: Peer supporters from five well-established peer support programs completed surveys (ProQOL and a five-item emotional exhaustion measure) to assess secondary traumatic stress, compassion satisfaction, and burnout during the pandemic. Analysis of variance models analyzed differences in these well-being outcomes by role, age, years in health care, and working in high-risk areas. Qualitative content analysis was performed for open-response questions about challenges, needs, and successful well-being strategies using Braun and Clarke's six-phase thematic analysis. RESULTS: A total of 375 peer supporters completed the survey between spring and summer 2021 for a response rate of about 38%. Most participants had low secondary traumatic stress and moderate to high compassion satisfaction; nearly 44% had concerning levels of emotional exhaustion. Compassion satisfaction was significantly lower (p = 0.003) and emotional exhaustion significantly higher (p < 0.001) among the youngest cohort, and both compassion satisfaction and emotional exhaustion differed across career stages (p = 0.003 and p = 0.04, respectively). Emotional exhaustion was significantly higher in peer supporters working in COVID units than in non-COVID units (p = 0.021). Peer supporters identified numerous protective and risk factors associated with serving as a peer supporter. CONCLUSION: Despite having moderate to high levels of compassion satisfaction, peer supporters report high levels of burnout and numerous challenges and needs to sustain their well-being. To maintain effective peer support programs during the ongoing pandemic, health care organizations must study and support the well-being of health care professional peer supporters.

Promotion of physical activity during weight loss maintenance: A randomized controlled trial.

OBJECTIVE: Behavioral weight loss (BWL) programs are not sufficiently effective at promoting high levels of moderate-to-vigorous physical activity (MVPA), despite the clear health benefits of exercise and the possibility that high levels of MVPA may improve long-term weight loss. This three-arm randomized controlled trial tested the hypotheses that 1) BWL interventions with an intensive focus on exercise would result in higher amounts of MVPA and greater long-term weight loss, compared to standard BWL, and 2) among interventions with an intensive focus on exercise, outcomes would be superior when skills for exercise promotion were taught from an acceptance-based theoretical framework (which fosters willingness to accept discomfort in the service of valued behaviors), versus a traditional behavioral approach. METHOD: Three hundred and twenty adults with overweight/obesity received group-based BWL for induction of weight loss (Months 1-6) and were randomized to receive one of three interventions for weight loss maintenance (Months 7-18): continued standard behavioral treatment (BT), behavioral treatment with an emphasis on exercise (BT + PA), or acceptance-based treatment with an emphasis on exercise (ABT + PA). RESULTS: MVPA and percent weight loss did not significantly differ by condition at 12 or 18 months. Participants engaging in relatively higher levels of MVPA had greater long-term weight losses compared to participants engaging in lower levels of MVPA. CONCLUSIONS: Further clinical innovations are needed so that participants in BWL programs can more readily adopt and maintain the recommended amounts of MVPA. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Harm avoidance as a mediator of treatment response to antidepressant treatment of patients with major depression.

BACKGROUND: The temperament harm avoidance (HA) has consistently demonstrated an association with major depressive disorder (MDD), serotonin functioning and reduction in depression symptoms in response to antidepressant medications targeting the serotonin system. In the current investigation, we examine HA as a potential mediator of treatment response to a serotonergic tricyclic antidepressant. METHODS: Outpatients (n = 150) with MDD were randomized to receive clomipramine or a control treatment. Patients completed the Hamilton Rating Scale for Depression (Ham-D) and the Tridimensional Personality Questionnaire (TPQ) prior to treatment initiation, and then again after at least 8 weeks of treatment. Using structural equation modeling, we evaluated a 'mediation model' in which change in HA is a mechanism of depression change in response to clomipramine, and a 'complication model' in which reduction in HA is a by-product of depression change. RESULTS: The mediation model provided a good fit to the data by all indices, whereas the complication model did not. Patients treated with clomipramine exhibited a greater decrease in HA as compared to those in the control group; moreover, HA reduction was associated with depression reduction. CONCLUSIONS: HA mediated the response to antidepressant treatment, such that any treatment effect of clomipramine occurred through HA reduction. Although replication with multiple assessment periods is required to determine if HA reduction actually precedes depression reduction, the results contribute to a growing body of literature implicating personality constructs subsumed within negative emotionality as mediators of treatment response to medications targeting serotonergic functioning.

Digital self-monitoring: Does adherence or association with outcomes differ by self-monitoring target?

OBJECTIVE: Digital self-monitoring of eating, physical activity, and weight is increasingly prescribed in behavioural weight loss programmes. This study determined if adherence rates or associations with outcomes differed according to self-monitoring target (ie, self-monitoring of eating versus physical activity versus weight). METHODS: Participants in a 3-month, group-based weight loss programme were instructed to use an app to record food intake, wear a physical activity sensor, and use a wireless body weight scale. At post-treatment, weight loss was measured in clinic and moderate-to-vigorous physical activity (MVPA) was measured by research-grade accelerometer. RESULTS: Adherence to self-monitoring decreased significantly over time for eating and weight but not physical activity. Overall, adherence to self-monitoring of weight was lower than that of eating or physical activity. Greater adherence to self-monitoring of eating, physical activity, and weight each predicted greater weight loss. Only greater adherence to self-monitoring of eating was associated with greater bouted minutes of MVPA. CONCLUSIONS: Findings from this study suggest that self-monitoring should be considered a target-specific behaviour rather than a unitary construct when conceptualizing adherence and association with treatment outcomes.

Change in Domain-specific but not General Psychological Flexibility Relates to Greater Weight Loss in Acceptance-Based Behavioral Treatment for Obesity.

Acceptance-based approaches have demonstrated promise for improving outcomes in behavioral treatments for obesity, but few studies have examined processes of change in these treatments. It is critical to identify mechanisms of action in treatment to further optimize this approach, refine theory, and inform future research. This study examined change in several domain-specific and general measures of psychological flexibility in a randomized controlled trial of an acceptance-based behavioral weight loss treatment. The relationships between change in these measures and weight loss outcomes were also examined. Adults (N = 283) were randomized to receive 12 months of acceptance-based (ABT) or non-acceptance-based (non-ABT) behavioral treatment and completed measures of general and weight control-specific psychological flexibility at months 0, 6, and 12. Participants in ABT demonstrated greater increases in psychological flexibility related to eating and physical activity experiences during treatment compared to participants in non-ABT, and changes in these processes were correlated with better weight loss. Parallel mediation analyses further revealed that psychological flexibility related to eating and physical activity experiences partially mediated the relationship between treatment condition and 12-month weight loss. Participants across conditions also experienced small increases in general psychological flexibility, but general psychological flexibility was not meaningfully related to weight loss outcomes. These findings indicate that domain-specific (versus general) psychological flexibility may be most impacted by ABT and most relevant to weight loss outcomes. Results also provide partial support for the theoretical model of ABT for weight management.