Racial differences in physical activity engagement, barriers, and enjoyment during weight loss.

OBJECTIVE: Aiming to identify potential intervention targets to achieve more equitable outcomes from behavioral weight loss (BWL) programs, the current study examined whether Black and White individuals experienced similar increases in physical activity (PA) engagement, perceived PA barriers, and PA enjoyment during an 18-month BWL program. METHOD: Adults (N = 290) enrolled in an 18-month BWL program from 2014 to 2016 completed accelerometer-based measurements of moderate-to-vigorous PA and self-reported measures of PA barriers and enjoyment at months 0, 6, 12, and 18. RESULTS: Black participants had significantly fewer minutes of PA than White participants at baseline, 6, 12, and 18 months. Black participants reported fewer barriers to PA than White participants at 0 and 6 months but not at 12 or 18 months. They also reported higher PA enjoyment than White participants at 0 and 6 months but not at 12 or 18 months. Furthermore, whereas White participants had a significant reduction in PA barriers and an increase in PA behavior overtime, Black participants did not. There was no interaction between race and time on PA enjoyment. CONCLUSIONS: Traditional BWL interventions may be ineffective for promoting PA among Black participants and may not appropriately address the unique PA barriers that Black participants experience. An improved understanding of differences in PA behaviors during BWL among Black and White individuals could help delineate why Black participants do not appear to benefit as much as White participants from traditional BWL programs and inform intervention strategies. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Psychological and behavioral responses to daily weight gain during behavioral weight loss treatment.

Self-weighing is consistently associated with more effective weight control. However, patterns show that participants disengage from their weight control behaviors following weight gain. Women with BMIs in the overweight/obese range (N = 50) enrolled in a long-term behavioral weight loss program completed ecological momentary assessment (EMA) surveys immediately after their daily weigh-ins. Nightly EMA surveys and self-monitoring data through Fitbit measured their weight control behavior that day. On days when participants gained weight (vs. lost or maintained), they reported more negative mood, more guilt/shame, and lower confidence in weight control. Motivation following daily weight gain depended on participants' overall satisfaction with their weight loss so far: more satisfied participants had marginally higher, but less satisfied participants had marginally lower motivation in response to daily weight gain. Greater guilt/shame and lower motivation after the weigh-in predicted less effective weight control behavior that day (e.g., lower likelihood of calorie tracking, fewer minutes of physical activity). Results demonstrate that even small weight gain is distressing and demoralizing for women in BWL programs, which can lead to goal disengagement. These findings have implications for future BWL interventions, including the potential utility of just-in-time adaptive interventions to promote more adaptive responses in the moments after weigh-ins.

Intraday relations between physical activity and energy intake among behavioral weight loss participants.

OBJECTIVE: Weight loss results from a negative energy balance, when energy intake (EI) is less than energy expended, e.g., from physical activity (PA). However, PA may impact energy balance beyond energy expenditure alone, through indirect effects on eating behavior. Yet, no research has examined if engaging in PA-a central component of most weight loss programs-is associated with same-day EI among individuals with overweight/obesity pursuing weight loss. METHOD: Adults (N = 101) with overweight/obesity in a weight loss program were prescribed a reduced-calorie diet and PA regimen (250 min of moderate-to-vigorous PA at midtreatment). For 3 weeks at midtreatment, PA and EI were measured via an accelerometer and self-monitoring app, respectively. Multilevel models examined within-person relations between PA and EI preceding PA ("pre-PA"), acutely following PA ("acute post-PA," the 2 hr following PA), in the time following the acute post-PA period ("remaining time in day"), and across entire PA days ("full-day"), relative to non-PA matched time periods. RESULTS: EI was higher in the pre-PA and acute post-PA periods. There were no reliable differences in EI during the remaining time in day nor across the full-day on PA days versus within-subject matched non-PA days. There also was insufficient evidence to suggest EI pre-PA, post-PA, or across entire PA days, relative to non-PA matched time periods, was associated with percent weight change. CONCLUSIONS: Findings suggest that engaging in PA was associated with different within-person EI patterns compared to non-PA days, though there was little evidence to support that these patterns relate to weight change. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Perceived importance of moderate-to-vigorous physical activity as a weight control strategy in behavioral weight loss.

Background: Previous research has established the importance of moderate-to-vigorous physical activity (MVPA) for weight control. One area of unexplored investigation is the relationship between individuals' perceptions of the importance of MVPA for weight control and MVPA engagement. This study examined the associations between the perceived importance of MVPA and MVPA engagement, weight loss, barriers to PA, and exercise enjoyment in adults enrolled in a long-term behavioral weight loss (BWL) intervention. Methods: Adults (N = 301) with overweight/obesity (BMI = 27-45 kg/m2) completed an 18-month BWL intervention, followed by a no-intervention 18-month follow-up. At baseline, 6 months, 18 months (i.e., post-treatment), and 36 months (i.e., follow-up), participants ranked the importance of six strategies for weight control: keeping a food record, MVPA, light PA, self-weighing, small portions, and low-calorie diet. Observed MVPA (measured by accelerometer), percent weight loss, perceived barriers to PA, and exercise enjoyment were also measured at each assessment. Results: Results showed that most participants perceived MVPA as a primary weight control strategy (first, second, or third most important) throughout the intervention, regardless of the weight control goal (weight loss vs. maintenance). Individuals who ranked MVPA as a primary strategy for weight control at concurrent time points, compared to those who did not, engaged in significantly more MVPA at post-treatment, had greater weight loss at follow-up, endorsed fewer barriers to PA at post-treatment and follow-up, and reported greater exercise enjoyment at baseline and post-treatment. Conclusion: Perceived importance of MVPA was related to subjective experiences of MVPA, MVPA adherence, and weight loss in a long-term BWL intervention.

A Proof-of-Concept Pilot Test of a Behavioral Intervention to Improve Adherence to Dietary Recommendations for Cancer Prevention.

OBJECTIVES: Prevention programs that can help adults improve the quality of their diets to reduce cancer risk are needed. This Phase IIa study prospectively tested a mHealth intervention designed to improve adherence to dietary quality guidelines for cancer prevention. METHODS: All participants (N = 62) received nutrition education and a self-regulation skills curriculum, with a primary target of changing grocery shopping behavior. Using a randomized, factorial design, the study varied whether each of the following 4 components were added to the 20-week intervention: (1) location-triggered app messaging, delivered when individuals arrived at grocery stores, (2) reflections on benefits of change, delivered with extra coaching time and tailored app messages, (3) coach monitoring, in which food purchases were digitally monitored by a coach, and (4) involvement of a household member in the intervention. RESULTS: Benchmarks were successfully met for recruitment, retention, and treatment acceptability. Across conditions, there were significant reductions in highly processed food intake (P < .001, η2 = .48), red and processed meat intake (P < .001, η2 = .20), and sugar-sweetened beverage intake (P = .008, η2 = .13) from pre-to post-treatment. Analyses examining whether each intervention component influenced change across time found that participants who received coach monitoring increased their intake of fruits, vegetables, and fiber, whereas those with no coach monitoring had less improvement (P = .01, η2 = .14). The improvement in red and processed meat was stronger among participants with household support ON, at a marginally significant level, than those with household support OFF (P = .056, η2 = .07). CONCLUSION: This study showed feasibility, acceptability, and preliminary signals of efficacy of a remotely delivered intervention to facilitate adherence to dietary guidelines for cancer prevention and that coach monitoring and household support may be especially effective strategies. A fully powered clinical trial is warranted to test an optimized version of the intervention that includes nutrition education, self-regulation skills training, coach monitoring, and household member involvement. TRIAL REGISTRATION: ClinicalTrials.gov NCT04947150.

Understanding the relationship between subclinical depressive symptoms and physical activity in behavioral weight loss treatment.

Introduction: Many adults with overweight or obesity experience subclinical symptoms of depression, but little is known about how such symptoms are associated with physical activity (PA) or the experience of PA during behavioral weight loss (BWL) treatment. Methods: In the current study, adults recruited from the community (N = 320) received 18 months of group-based BWL treatment and wore accelerometers at months 0, 6, and 18 to objectively measure PA. Participants with a mood disorder that was not well controlled were not eligible for the study and were referred for individual treatment. Depressive symptoms, PA barriers, discomfort avoidance, and self-control were self-reported with validated measures. Results: At baseline, the majority of participants indicated some depressive symptoms, mostly at subclinical levels. Results of multilevel models suggest that depressive symptoms were not significantly associated with concurrent measures of PA engagement (minutes/week) or sedentary behavior (minutes/week) at a given time point (i.e., baseline, 6 months, or 18 months). Results of cross-level interactions suggest that baseline depressive symptoms did not moderate the change in PA or sedentary behavior across time. Concurrent depressive symptoms and PA barriers were significantly and positively associated at a given time point (i.e., baseline, 6 months, or 18 months); however, baseline depressive symptoms did not moderate the improvement in perceived PA barriers across time. At baseline, higher discomfort avoidance and lower self-control each independently and partially mediated the relationship between depressive symptoms and PA barriers. Conclusion: Results suggest that, among BWL samples in which most participants do not have clinically significant depressive symptoms, the likelihood of adopting and sustaining PA does not depend on the extent of depressive symptoms, but those with elevated symptoms may benefit from approaches that address their perception that engaging in PA is especially challenging.

Latent Profile Analysis of Physical Activity Motivation during Behavioral Weight Loss Treatment.

Participants in behavioral weight loss (BWL) treatment often struggle to meet and maintain physical activity (PA) prescriptions; improving participants' motivation for the behavior is a potential intervention strategy. Self-Determination Theory (SDT) outlines a continuum of qualitatively different dimensions of motivation, suggesting that more self-determined forms of motivation should predict more PA, whereas less self-determined forms of motivation should be unrelated or negatively related to PA. Although SDT has ample empirical support, most existing research in this area has used statistical analyses that oversimplify the complex, interdependent relationships between dimensions of motivation and behavior. This study's purpose was to explore commonly occurring motivational "profiles" for PA based on the SDT dimensions of motivation (amotivation, external, introjected, integrated/identified, and intrinsic motivation) and how these profiles relate to PA behavior among participants with overweight/obesity (N=281, 79.4% female) at baseline and six months into BWL treatment. Latent profile analysis determined that three motivational profiles fit the data best at both timepoints and the profile characterized by high self-determined (i.e., integrated/identified and intrinsic) motivation and moderate introjected motivation was by far the most common. There were no differences in physical activity behavior across motivational profiles, which contrasts previous literature. Findings suggest that participants who take the initiative to sign up for intensive BWL programs may have sufficiently high PA motivation, which may be a poor predictor of their actual behavior. Future research should examine these relationships later in treatment, when motivation may have more variability, as well as among participants who initiate lower-commitment weight loss programs (e.g., self-help).

Sharing digital self-monitoring data with others to enhance long-term weight loss: A randomized controlled trial.

BACKGROUND: Participants in behavioral weight loss (BWL) programs increasingly use digital tools to self-monitor weight, physical activity, and dietary intake. Data collected with these tools can be systematically shared with other parties in ways that might support behavior change. METHODS: Adults age 18 to 70 with overweight/obesity (BMI 27-50 kg/m2) will enroll in a remotely delivered, 24-month BWL program designed to produce and maintain a 10% weight loss. Participants will be asked to use a wireless body weight scale, wearable activity sensor, and dietary intake app daily. All participants will receive individual and group counseling, engage in text messaging with members of their group, and appoint a friend or family member to serve in a support role. A 2x2x2 factorial design will test the effects of three types of data sharing partnerships: 1) Coach Share: The behavioral coach will regularly view digital self-monitoring data and address data observations. 2) Group Share: Participants will view each other's self-monitoring data in small-group text messages. 3) Friend/Family Share: A friend or family member will view the participant's data via automated message. The primary outcome is weight loss at 24 months. Mediators and moderators of intervention effects will be tested. CONCLUSION: This study will provide a clear indication of whether data sharing can improve long-term weight loss. This study will be the first to discern the mechanisms of action through which each type of data sharing may be beneficial, and elucidate conditions under which the benefits of data sharing may be maximized.

Overlapping and distinct relationships between hedonic hunger, uncontrolled eating, food craving, and the obesogenic home food environment during and after a 12-month behavioral weight loss program.

Hedonic hunger, reward-driven eating outside of biological need, is a newer construct in eating behavior research. During behavioral weight loss (BWL), greater improvements in hedonic hunger are associated with higher weight loss, but it remains unclear if hedonic hunger predicts weight loss independent of more well-established, similar constructs (uncontrolled eating and food craving). Research also is needed to understand how hedonic hunger interacts with contextual factors (e.g., obesogenic food environment) during weight loss. Adults (N = 283) in a 12-month randomized controlled trial of BWL were weighed at 0, 12, and 24 months, and completed questionnaires assessing hedonic hunger, food craving, uncontrolled eating, and the home food environment. All variables improved at 12 and 24 months. Decreases in hedonic hunger at 12 months were associated with higher concurrent weight loss, but not when accounting for improvements in craving and uncontrolled eating. At 24 months, reduction in craving was a stronger predictor of weight loss than hedonic hunger, but improvement in hedonic hunger was a stronger predictor of weight loss than change in uncontrolled eating. Changes to the obesogenic home food environment failed to predict weight loss, regardless of levels of hedonic hunger. This study adds novel information on the individual and contextual factors associated with short- and long-term weight control, which can help refine conceptual models and treatment strategies.

Enhancing Efficacy of a Brief Obesity and Eating Disorder Prevention Program: Long-Term Results from an Experimental Therapeutics Trial.

Objective: Test whether the efficacy of Project Health, an obesity/eating disorder prevention program, is improved by delivering it in single-sex groups and adding food response inhibition and attention training. Method: High-risk young adults (N = 261; M age = 19.3, 74% female) were randomized to (1) single-sex or (2) mixed-sex groups that completed food response inhibition and attention training or (3) single-sex or (4) mixed-sex groups that completed sham training with nonfood images in a 2 × 2 factorial design. Results: There was a significant sex-composition by training-type by time interaction; participants who completed single- or mixed-sex Project Health groups plus food response and attention training showed significant reductions in body fat over a 2-year follow-up, though this effect was more rapid and persistent in single-sex groups, whereas those who completed single- or mixed-sex Project Health groups plus sham training did not show body fat change. However, there were no differences in overweight/obesity onset over the follow-up. The manipulated factors did not affect eating disorder symptoms or eating disorder onset, but there was a significant reduction in symptoms across the conditions (within-condition d = -0.58), converging with prior evidence that Project Health produced larger reductions in symptoms (within-condition d = -0.48) than educational control participants. Average eating disorder onset over the 2-year follow-up (6.4%) was similar to that observed in Project Health in a past trial (4.5%). Conclusions: Given that Project Health significantly reduced future onset of overweight/obesity in a prior trial and the present trial found that body fat loss effects were significantly greater when implemented in single-sex groups and paired with food response and attention training, there might be value in broadly implementing this combined intervention.

Do monthly coaching calls influence proximal participant adherence in a behavioral weight loss program?

Participants who receive continued coach contact following behavioral weight loss treatment are more successful in maintaining their weight loss long-term. The current study examines whether these contacts have dynamic effects, such that participants are most adherent to the prescribed weight loss behaviors in the days after the call, when motivation and goal salience may be heightened, than they are as time goes on. The current study examined the trajectory of calorie intake, physical activity, weight, and self-monitoring behavior in the fourteen days after a monthly coaching call among participants completing the maintenance phase of a behavioral weight loss trial. For physical activity outcomes, caloric intake, and weight, there were no changes across time. Participants did have the highest adherence and quality of dietary self-monitoring immediately after the call, which diminished over time. Coach contact may continually renew commitment to this burdensome but critical behavior. Likelihood of self-weighing showed an opposite trend, where participants were more likely to weigh themselves in the days more distal from the coach call. Results can inform the timing and content of future coach contact to promote weight control.

Social comparisons between group members during behavioural weight loss treatment: comparison direction, scale, and associations with weight loss maintenance.

OBJECTIVE: To examine distinct types of social comparisons (i.e. self-evaluations relative to others) in behavioural weight loss groups and their relations with weight loss maintenance. DESIGN: Participants (N = 127, MBMI = 35.66 kg/m2) reported on their comparisons at mid-treatment (6 months), including identification of their primary individual comparison target (group member) and perceptions of their own treatment adherence versus that of their group and identified target. MAIN OUTCOME MEASURES: Weight was assessed at baseline, mid-treatment, end-of-treatment (12 months), and 18- and 24-month follow-ups. RESULTS: Comparisons with individual targets perceived as more successful with weight loss were most frequent (i.e. upward comparisons), though comparisons differed based on group versus individual targets and specific treatment behaviours (e.g. self-monitoring). Comparisons did not align with participants' own treatment progress, suggesting that comparisons reflect more than just their objective weight loss relative to others. Relations between participants' initial weight loss and maintenance was moderated by the type of individual target identified at mid-treatment (p = 0.02, sr = 0.27). CONCLUSIONS: Social comparisons in group-based weight loss treatment are multifaceted and predict long-term weight loss maintenance. Additional work is needed to determine how best to harness comparison processes to promote success in behavioural weight loss treatment.

The Role of Physical Activity in Long-term Weight Loss: 36-month Results From a Randomized Controlled Trial.

BACKGROUND: Physical activity (PA) may promote long-term weight loss, but facilitating high levels of PA in behavioral weight loss programs is challenging. PURPOSE: This study reports the 36-month follow-up of a behavioral weight loss trial that tested the efficacy of increasing the emphasis on PA during treatment and using traditional or acceptance-based therapy (ABT) for this purpose. We also examined the extent to which long-term weight loss differed by PA pattern and tested if individual differences in eating behavior moderated this relationship. METHODS: Participants (N = 320) were randomized to (1) standard behavioral weight loss treatment (BT), (2) BT with a focus on PA, or (3) ABT with a focus on PA. Weight loss and PA were measured at 24- and 36-month follow-up. RESULTS: There were no differences between conditions in weight loss or PA at 24 or 36 months. Participants consistently engaging in high PA experienced the greatest weight losses. The positive impact of PA on weight loss was more pronounced among those with low emotional eating and those who believed that exercise did not affect their appetite. CONCLUSIONS: Findings emphasize the difficulty of improving long-term PA among adults with overweight/obesity beyond what standard behavioral weight loss treatment achieves. This study highlights the need to develop new PA treatment strategies, and suggests that ABT for weight loss may be more effective when applied to eating behavior versus PA. Results also demonstrate the importance of addressing problematic eating behavior and cognitions to fully realize the benefits of PA for weight loss. CLINICAL TRIAL INFORMATION: ClinicalTrials.gov identifier: NCT02363010.

Using artificial intelligence to optimize delivery of weight loss treatment: Protocol for an efficacy and cost-effectiveness trial.

Gold standard behavioral weight loss (BWL) is limited by the availability of expert clinicians and high cost of delivery. The artificial intelligence (AI) technique of reinforcement learning (RL) is an optimization solution that tracks outcomes associated with specific actions and, over time, learns which actions yield a desired outcome. RL is increasingly utilized to optimize medical treatments (e.g., chemotherapy dosages), and has very recently started to be utilized by behavioral treatments. For example, we previously demonstrated that RL successfully optimized BWL by dynamically choosing between treatments of varying cost/intensity each week for each participant based on automatic monitoring of digital data (e.g., weight change). In that preliminary work, participants randomized to the AI condition required one-third the amount of coaching contact as those randomized to the gold standard condition but had nearly identical weight losses. The current protocol extends our pilot work and will be the first full-scale randomized controlled trial of a RL system for weight control. The primary aim is to evaluate the hypothesis that a RL-based 12-month BWL program will produce non-inferior weight losses to standard BWL treatment, but at lower costs. Secondary aims include testing mechanistic targets (calorie intake, physical activity) and predictors (depression, binge eating). As such, adults with overweight/obesity (N = 336) will be randomized to either a gold standard condition (12 months of weekly BWL groups) or AI-optimized weekly interventions that represent a combination of expert-led group, expert-led call, paraprofessional-led call, and automated message). Participants will be assessed at 0, 1, 6 and 12 months.

Wellness Achieved Through Changing Habits: A Randomized Controlled Trial of an Acceptance-Based Intervention for Adolescent Girls With Overweight or Obesity.

Background: Obesity prevalence among adolescent girls continues to rise. Acceptance-based therapy (ABT) is effective for weight loss in adults and feasible and acceptable for weight loss among adolescents. This pilot randomized controlled trial (RCT) assessed effectiveness of an adolescent-tailored ABT intervention on decreasing weight-related outcomes and improving psychological outcomes compared with enhanced care. Methods: In this 6-month, two-arm pilot RCT, participants were randomized to the ABT intervention or to enhanced care. The ABT intervention condition attended 15 virtual, 90-minute group sessions. The enhanced care comparison received 15 healthy lifestyle handouts and virtually met twice with a registered dietitian. The primary outcome assessed was change in BMI expressed as a percentage of the 95th percentile (%BMIp95). Results: Participants included 40 girls (ages 14-19) assigned to ABT (n = 20) or enhanced care (n = 20). A decrease in %BMIp95 was observed within the ABT intervention [d = -0.19, 95% confidence interval, CI: (-0.36 to -0.02)], however, not within the enhanced care comparison [d = -0.01, 95% CI: (-0.09 to 0.07)]. The ABT group showed slight changes in psychological flexibility [d = -0.34, 95% CI: (-0.62 to -0.06)] over enhanced care [d = -0.11, 95% CI: (-0.58 to 0.37)]. There was no significant intervention effect noted between groups. Conclusion: In this pilot RCT, the ABT intervention was as effective as enhanced care for weight loss. However, previous ABT studies occurred in person, and this study was conducted virtually due to COVID-19. Thus, future research investigating the potential effectiveness of ABT in-person among adolescents and optimization of virtual interventions is needed.

Gamification and neurotraining to engage men in behavioral weight loss: Protocol for a factorial randomized controlled trial.

Over 70% of men are overweight, and most desire weight loss; however, men are profoundly underrepresented in weight loss programs. Gamification represents a novel approach to engaging men and may enhance efficacy through two means: (1) game-based elements (e.g., streaks, badges, team-based competition) to motivate weight control behaviors and (2) arcade-style "neurotraining" to enhance neurocognitive capacities to resist the temptation of unhealthy foods and more automatically select healthy foods. This study will use a 2 × 2 factorial design to examine the independent and combinatory efficacy of gamification and inhibitory control training (ICT). Men with overweight/obesity (N = 228) will receive a 12-month mobile weight loss program that incorporates behavioral weight loss strategies (e.g., self-monitoring, goal setting, stimulus control). Men will be randomly assigned to a non-gamified or gamified version, and an active or sham ICT. A game design company will create the program, with input from a male advisory panel. Aims of the project are to test whether a gamified (versus non-gamified) weight loss program and/or ICT (versus sham) promotes greater improvements in weight, diet, and physical activity; whether these treatment factors have combinatory or synergistic effects; to test whether postulated mechanisms of action (increased engagement, for gamification, and inhibitory control, for ICT) mediate treatment effects; and whether baseline gameplay frequency and implicit preferences for ICT-targeted foods moderate effects. It is hoped this study will contribute to improved mHealth programs for men and enhance our understanding of the impact of gamified elements and neurocognitive training on weight control.

Understanding the role of sex on outcomes for the cancer patient undergoing treatment with immune checkpoint inhibitors: a scoping review protocol.

INTRODUCTION: Immune checkpoint inhibitors (ICIs) have changed the treatment landscape for multiple cancer types. Sex plays an important role in both the development of cancer as well as the functioning of the immune system. Though a difference in response to immune therapy is emerging between men and women it is unclear how this difference affects cancer outcomes and what the potential underlying mechanisms are for those effects. The objective of this study is to describe the influence that sex has on the outcomes experienced by cancer patients on ICI therapy and to identify and analyse any knowledge gaps in the field. METHOD AND ANALYSIS: The framework for this methodology was guided by the Joanna Briggs Institute Manual for Evidence Synthesis. The search and review will be conducted from January 2022 to June 2022. Two independent researchers will screen titles and abstracts followed by full-text screening for manuscript inclusion. Full length studies published between 2010 and December 2021 found in PubMed, Cochrane, CINAHL, and Scopus describing the influence of sex differences on cancer outcomes in patients treated with ICIs will be included. After data are extracted it will be summarised for presentation. ETHICS AND DISSEMINATION: The findings of this scoping review will be published in a peer-reviewed journal. The results will be used to inform future studies on the potential differential impacts of ICIs. All data are from published openly accessible sources and therefore no ethical clearance is necessary.

Subjective experiences of physical activity and forecasting bias during behavioral weight loss.

Introduction: Engagement in physical activity (PA) is a critical component of behavioral weight loss (BWL) treatment. Subjective experiences surrounding PA may shape exercise decisions and need to be further understood within a BWL sample. Methods: Participants in this study were adults with overweight/obesity enrolled in an 18-month BWL program. At baseline, six, and 18 months, participants (N = 320) predicted how they would feel during a lab-based walking task and rated their experiences mid-walk and post-walk. They also completed self-report questionnaires assessing depressive symptoms and discomfort intolerance. Results and Discussion: Results indicated that exercise experience and expectations were more positive at later treatment points than at baseline. At each assessment point, post-walk ratings were more positive than mid-walk ratings, but pre-walk ratings did not differ from mid-walk ratings, suggesting BWL participants were relatively accurate in predicting their PA experience. These results suggest treatment-seeking adults with overweight/obesity feel most positive upon completion of PA, may not experience a forecasting bias as hypothesized and seem to have increasingly positive PA expectations and experiences as they proceed through treatment and lose weight. Lower discomfort intolerance and depressive symptoms were associated with more positive PA expectations and experiences. Understanding these individual differences in PA experience can inform intervention strategies.

Optimizing an mHealth Intervention to Change Food Purchasing Behaviors for Cancer Prevention: Protocol for a Pilot Randomized Controlled Trial.

BACKGROUND: Dietary intake is a powerful modifiable factor that influences cancer risk; however, most US adults do not adhere to dietary guidelines for cancer prevention. One promising pathway for improving dietary adherence is targeting grocery shopping habits. Interventions might facilitate healthy grocery choices, with a combination of mHealth and traditional methods, by promoting the salience of dietary goals while shopping, enhancing motivation to make dietary changes, and increasing household support for healthy food purchasing. OBJECTIVE: This pilot study will assess feasibility and acceptability of intervention components designed to improve adherence to dietary guidelines for cancer prevention (preliminary aim). The primary aim of the study is to quantify the effect of each intervention component, individually and in combination, on dietary intake (primary aim) and grocery store food purchases (exploratory aim). Mediation analyses will be conducted to understand the mechanisms of action (goal salience, motivation, and household support-secondary aims). The overarching goal is to optimize an mHealth intervention to be tested in a future fully powered clinical trial. METHODS: The study enrolled adults (N=62) with low adherence to dietary recommendations for cancer prevention. In a 20-week program, all participants attend a nutrition education workshop and receive weekly educational messages through an app. A factorial design is used to test 4 intervention components: (1) location-triggered messages: educational messages are delivered when arriving at grocery stores; (2) reflections on the benefits of change: content is added to messages to encourage reflection on anticipated benefits of healthy eating, and participants attend an additional workshop session and 3 coach calls on this topic; (3) coach monitoring: food purchases are monitored digitally by a coach who sends personalized weekly app messages and conducts 3 coaching calls that focus on feedback about purchases; and (4) household support: another adult in the household receives messages designed to elicit support for healthy food purchasing, and support is addressed in 3 coach calls and an extra workshop session attended by the index participant and household member. Assessments are completed at weeks 0, 10, and 20 using self-report measures, as well as objective capture of grocery data from the point of purchase using store loyalty accounts. RESULTS: The National Cancer Institute funded this study (R21CA252933) on July 7, 2020. Participant recruitment began in the spring of 2021 and concluded with the successful enrollment of 62 participants. Data collection is expected to be completed in the summer of 2022, and results are expected to be disseminated in the summer of 2023. CONCLUSIONS: The results of this study will inform the development of scalable interventions to lower cancer risk via changes in dietary intake. TRIAL REGISTRATION: ClinicalTrials.gov NCT04947150; https://clinicaltrials.gov/ct2/show/NCT04947150. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/39669.

The Relation of Grit to Weight Loss Maintenance Outcomes.

Biological, genetic, and environmental factors make weight loss very difficult. Acceptance-based behavioral treatment (ABT) supplements standard behavioral treatments (BT) for obesity by teaching skills to accept the discomfort inherent to weight control behaviors and prioritize long-term, values-based goals. Grit, the ability to persevere in goal pursuit, overlaps conceptually with ABT principles and may predict outcomes in ABT. During a randomized controlled trial comparing three weight loss interventions (BT, BT with an emphasis on physical activity [BT+PA], ABT with an emphasis on physical activity [ABT+PA]), this study examined if grit predicted weight loss, intervention engagement (session attendance and dietary self-monitoring), and perceived intervention effectiveness, and whether intervention condition moderated these relationships. Participants (N=309) with overweight/obesity enrolled in an 18-month weight loss intervention completed the Short Grit Scale at baseline. Weight and PA were measured at baseline, during the intervention (12 and 18 months), and at follow-up (24 and 36 months). Session attendance and dietary self-monitoring were assessed throughout the intervention, and perceived intervention effectiveness at end-of-intervention. The relation of grit to several outcomes depended on condition. In ABT+PA, but not BT or BT+PA, lower grit related to higher weight loss at 12 and 24 months, session attendance, and perceived intervention effectiveness. Grit was not related to PA or dietary self-monitoring in any condition. ABT's focus on building skills to facilitate long-term goal pursuit may be unique and beneficial to those with lower grit. Those with higher grit may already possess ABT-consistent skills and benefit less from ABT. Research on trait-level characteristics like grit in relation to weight must be cautious not to reinforce weight bias; rather, this work suggests that an evidence-based intervention (ABT) may be well-suited to those with lower grit levels seeking weight loss.