Behavioral Weight Loss Intervention Research Articles

The role of group cohesion in a group-based behavioral weight loss intervention.

Behavioral weight loss interventions are often delivered in groups. Group cohesion may enhance program attendance and, thereby, weight loss. In this secondary analysis, our goals were to: (1a) assess whether group cohesion measured early in a behavioral weight loss intervention predicts program attendance and weight loss outcomes and, if so, (1b) explore whether attendance mediates the link between group cohesion and weight loss; (2) characterize the association between change in group cohesion and weight loss throughout the intervention. Veterans (n=324) initiated a 16-week, group-based behavioral weight loss program involving biweekly in-person group visits. In linear regression models, early group cohesion was unrelated to group attendance or weight loss. Although group cohesion significantly increased during the intervention, this change was not associated with weight loss. These findings are consistent with the limited literature; however, they are inconsistent with theoretical assertions and clinical observations of the influence of group factors on outcomes.

Bidirectional Relationships Between Weight Change and Sleep Apnea in a Behavioral Weight Loss Intervention

ObjectiveTo examine the bidirectional relationship between weight change and obstructive sleep apnea (OSA) in the context of a behavioral weight loss intervention. Patients and MethodsAdults who were overweight or obese (N=114) participated in a 12-month behavioral weight loss intervention from April 17, 2012, through February 9, 2015. The apnea-hypopnea index (AHI), a marker of the presence and severity of OSA, was assessed at baseline, 6 months, and 12 months. Linear mixed models evaluated the effect of weight change on the AHI and the effect of OSA (AHI ≥5) on subsequent weight loss. Secondary analyses evaluated the effect of OSA on intervention attendance, meeting daily calorie goals, and accelerometer-measured physical activity. ResultsAt baseline, 51.8% of the sample (n=59) had OSA. Adults who achieved at least 5% weight loss had an AHI reduction that was 2.1±0.9 (adjusted mean ± SE) events/h greater than those with less than 5% weight loss (P<.05). Adults with OSA lost a mean ± SE of 2.2%±0.9% less weight during the subsequent 6-month interval compared with those without OSA (P=.02). Those with OSA were less adherent to daily calorie goals (mean ± SE: 25.2%±3.3% vs 34.8%±3.4% of days; P=.006) and had a smaller increase in daily activity (mean ± SE: 378.3±353.7 vs 1060.1±377.8 steps/d; P<.05) over 12 months than those without OSA. ConclusionBehaviorally induced weight loss in overweight/obese adults was associated with significant AHI reduction. However, the presence of OSA was associated with blunted weight loss, potentially via reduced adherence to behaviors supporting weight loss. These results suggest that OSA screening before attempting weight loss may be helpful to identify who may benefit from additional behavioral counseling.

"Last Supper" Predicts Greater Weight Loss Early in Obesity Treatment, but Not Enough to Offset Initial Gains.

Background: Many participants experience clinically significant fluctuations in weight before beginning a behavioral weight loss program. Pre-treatment weight gain, often referred to as the “last supper” effect, may limit total weight loss from the time of the pre-treatment screening visit and could be an indicator that a participant will respond poorly to behavioral intervention.Methods: Data were from the weight loss phase of a two-phase weight loss maintenance trial, in which 178 participants with obesity (screening BMI = 40.5 ± 6.0 kg/m2, 87.6% female; 71.3% black) were provided with a 14 week lifestyle intervention that included a meal replacement diet. Participants were categorized as having gained >1.15%, remained weight stable, or lost >1.15% of initial weight between the pre-treatment screening visit and the first treatment session (48.7 ± 29.4 days). We first examined whether the weight change groups differed in baseline eating characteristics (e.g., emotional eating, self-regulation, craving frequency) using one-way ANCOVAs. Linear mixed models were then used to compare weight change groups on total weight loss from the screening visit to week 14 and in-treatment weight loss from weeks 1 to 14.Results: Nearly half of the sample (48.9%) gained >1.15% of initial weight during the pre-treatment period (+2.5 ± 1.2%); 41.0% remained weight stable (+0.2 ± 0.6%); and 10.1% lost >1.15% of initial weight (-2.2 ± 0.9%). There were no significant differences between the groups in baseline eating characteristics. As measured from the screening weight, the weight-gain group had a lower total loss of 6.8%, compared to 7.8% in the weight stable group (p = 0.02) and 9.0% in the weight-loss group (p = 0.003). The weight-gain group lost more weight in the first 4 weeks of treatment, but in-treatment losses did not differ among the groups at week 14.Conclusion: Pre-treatment weight gain was not an indicator of a poor response to a behavioral weight loss intervention and was associated with greater weight loss early in treatment. However, weight gain during the pre-treatment period may limit the total weight loss that participants achieve from the time that they first enroll in a weight loss program.

Disordered Eating Attitudes and Behaviors in Youth with Overweight and Obesity: Implications for Treatment.

Children with obesity experience disordered eating attitudes and behaviors at high rates, which increases their risk for adult obesity and eating disorder development. As such, it is imperative to screen for disordered eating symptoms and identify appropriate treatments. Family-based multicomponent behavioral weight loss treatment (FBT) is effective at treating childhood obesity and demonstrates positive outcomes on psychosocial outcomes, including disordered eating. FBT utilizes a socio-ecological treatment approach that focuses on the development of individual and family healthy energy-balance behaviors as well as positive self- and body esteem, supportive family relationships, richer social networks, and the creation of a broader environment and community that facilitates overall physical and mental health. Existing literature suggests FBT is an effective treatment option for disordered eating and obesity in children. Future work is needed to confirm this conclusion and to examine the progression and interaction of obesity and disordered eating across development to identify the optimal time for intervention.

Perceived barriers and facilitators of initiation of behavioral weight loss interventions among adults with obesity: a qualitative study

BackgroundEvidence-based behavioral weight loss interventions are under-utilized. To inform efforts to increase uptake of these interventions, it is important to understand the perspectives of adults with obesity regarding barriers and facilitators of weight loss intervention initiation.MethodsWe conducted a qualitative study in adults with obesity who had recently attempted weight loss either with assistance from an evidence-based behavioral intervention (intervention initiators) or without use of a formal intervention (intervention non-initiators). We recruited primary care patients, members of a commercial weight loss program, and members of a Veterans Affairs weight loss program. Intervention initiators and non-initiators were interviewed separately using a semi-structured interview guide that asked participants about barriers and facilitators of weight loss intervention initiation. Conversations were audio-recorded and transcribed. Data were analyzed with qualitative content analysis. Two researchers used open coding to generate the code book on a subset of transcripts and a single researcher coded remaining transcripts. Codes were combined into subthemes, which were combined in to higher order themes. Intervention initiators and non-initiators were compared.ResultsWe conducted three focus groups with participants who had initiated interventions (n = 26) and three focus groups (n = 24) and 8 individual interviews with participants who had not initiated interventions. Intervention initiators and non-initiators were, respectively, 65% and 37.5% white, 62% and 63% female, mean age of 55 and 54 years old, and mean BMI of 34 kg/m2. Three themes were identified. One theme was practical factors, with subthemes of reasonable cost and scheduling compatibility. A second theme was anticipated effectiveness of intervention, with subthemes of intervention content addressing individual needs; social aspects influencing effectiveness; and evaluating evidence of effectiveness. A third theme was anticipated pleasantness of intervention, with subthemes of social aspects influencing enjoyment; anticipated dietary and tracking prescriptions; and identity and self-reliance factors. Different perspectives were identified from intervention initiators and non-initiators.ConclusionsStrategies to engage individuals in evidence-based weight loss interventions can be developed using these results. Strategies could target individuals’ perceived barriers and benefits to initiating interventions, or could focus on refining interventions to appeal to more individuals.

Developing an Acceptance-Based Behavioral Weight Loss Treatment for Individuals With Binge Eating Pathology: A Preliminary Proof of Concept Study and Clinical Case Series

Binge eating (BE; i.e., the consumption of a large amount of food in a discrete time period, accompanied by a sense of loss of control) is highly comorbid with overweight or obesity and is the primary symptom of binge eating disorder (BED). Current gold-standard treatment for BED (i.e., CBT) does not produce meaningful weight loss, thus failing to address a critical treatment target. This article describes the development of a novel acceptance-based behavioral treatment (ABBT) for individuals with clinically significant BE desiring to reduce BE symptoms and achieve concurrent weight loss. We discuss the development and structure of the novel treatment approach, and describe the test of a proof of concept version of the treatment in a clinical case series of four individuals. In the context of each clinical case description, we present initial acceptability of the treatment and challenges faced in treatment development and delivery. Finally, we discuss future research directions for the treatment, which could improve BE symptoms and weight loss outcomes for individuals with BE pathology.

Greater improvements in diet quality among overweight participants following a group-based commercial weight loss programme than those receiving support to lose weight in primary care

BackgroundRelatively little is known about dietary changes and their relationships with weight change during behavioural weight loss interventions. In a secondary analysis of data from a multicentre RCT, we investigated whether greater improvements in diet would be achieved by overweight adults following a 12 month group-based commercial weight loss programme (CP) than those receiving standard care (SC) in primary practice, and if these dietary changes were associated with greater weight loss.MethodsAdults with a BMI 27–35 kg/m2 and >1 risk factor for obesity-related disorders were recruited in study centres in Australia and the UK during 2007–2008. Dietary intake and body weight were measured at baseline, 6 and 12 months. Linear mixed effects models compared mean changes in dietary macronutrient intake, fibre density and energy density over time between groups, and their relationships with weight loss.ResultsThe CP group demonstrated greater mean weight loss than the SC group at 6 months (3.3 kg, 95% CI: 2.2, 4.4) and 12 months (3.3 kg, 95% CI: 2.1, 4.5). Diet quality improved in both intervention groups at 6 and 12 months. However, the CP group (n = 228) achieved significantly greater mean reductions in energy intake (mean difference; 95% CI: − 503 kJ/d; − 913, − 93), dietary energy density (− 0.48 MJ/g; − 0.81, − 0.16), total fat (− 6.9 g/d; − 11.9, − 1.8), saturated fat (− 3.3 g/d; − 5.4, − 1.1), and significantly greater mean increases in fibre density (0.30 g/MJ; 0.15, 0.44) at 6 months than the SC group (n = 239). Similar differences persisted at 12 months and the CP group showed greater mean increases in protein density (0.65 g/MJ). In both groups, weight loss was associated with increased fibre density (0.68 kg per g/MJ, 95% CI: 0.08, 1.27) and protein density (0.26 kg per g/MJ, 95% CI: 0.10, 0.41).ConclusionsFollowing a group-based commercial program led to greater improvements in diet quality than standard care. Increases in dietary protein and fibre density were independently associated with weight loss in both behavioural weight loss interventions. Greater increases in protein and fibre density in the commercial program likely contributed to their greater weight loss.Trial registrationISRCTN: ISRCTN85485463 Registered 03/08/2007 Retrospectively Registered.

Using ecological momentary assessment to better understand dietary lapse types

Frequency of lapsing from a diet predicts weight loss failure, however previous studies have only utilized one definition of dietary lapse. No study has examined different types of lapse behaviors among individuals with overweight/obesity. The current study uses ecological momentary assessment (EMA) to examine predictors of three lapse types—eating a larger portion than intended, eating an unintended type of food, and eating at an unplanned time—in adults (N = 189; MBMI = 36.93 ± 5.83 kg/m2; 82.0% female; Mage = 51.81 ± 9.76 years) enrolled in a 12-month randomized controlled trial of two behavioral weight loss treatments. Participants completed 14 days of EMA at the start of treatment during which they indicated types of lapses that occurred with time and location of the lapse. Participants also responded to questions assessing current physical (e.g., hunger, tiredness), environmental (e.g., presence of “delicious” foods), and affective (e.g., loneliness, sadness) states at each prompt. Weight change was assessed at post-treatment. Separate generalized estimating equations were used to examine whether states prospectively predicted lapse occurrence at the next survey. Results indicated that lapse types differed significantly across time and location. Momentary increases in deprivation, hunger, and boredom increased likelihood of different lapse types. Lastly, we examined the prospective association between lapse type and weight loss. Eating at an unintended time was the only lapse type that predicted worse weight loss outcomes. Results support the theory that distinct lapse types exist, and that lapse types can be predicted by both momentary conditions and individual tendencies toward certain physical and affective states. However, not all lapse types may impact weight outcomes. Future research on behaviors that constitute dietary lapse is warranted and could inform personalized weight loss treatments.

Using the Habit App for Weight Loss Problem Solving: Development and Feasibility Study.

BackgroundReviews of weight loss mobile apps have revealed they include very few evidence-based features, relying mostly on self-monitoring. Unfortunately, adherence to self-monitoring is often low, especially among patients with motivational challenges. One behavioral strategy that is leveraged in virtually every visit of behavioral weight loss interventions and is specifically used to deal with adherence and motivational issues is problem solving. Problem solving has been successfully implemented in depression mobile apps, but not yet in weight loss apps.ObjectiveThis study describes the development and feasibility testing of the Habit app, which was designed to automate problem-solving therapy for weight loss.MethodsTwo iterative single-arm pilot studies were conducted to evaluate the feasibility and acceptability of the Habit app. In each pilot study, adults who were overweight or obese were enrolled in an 8-week intervention that included the Habit app plus support via a private Facebook group. Feasibility outcomes included retention, app usage, usability, and acceptability. Changes in problem-solving skills and weight over 8 weeks are described, as well as app usage and weight change at 16 weeks.ResultsResults from both pilots show acceptable use of the Habit app over 8 weeks with on average two to three uses per week, the recommended rate of use. Acceptability ratings were mixed such that 54% (13/24) and 73% (11/15) of participants found the diet solutions helpful and 71% (17/24) and 80% (12/15) found setting reminders for habits helpful in pilots 1 and 2, respectively. In both pilots, participants lost significant weight (P=.005 and P=.03, respectively). In neither pilot was an effect on problem-solving skills observed (P=.62 and P=.27, respectively).ConclusionsProblem-solving therapy for weight loss is feasible to implement in a mobile app environment; however, automated delivery may not impact problem-solving skills as has been observed previously via human delivery.Trial RegistrationClinicalTrials.gov NCT02192905; https://clinicaltrials.gov/ct2/show/NCT02192905 (Archived by WebCite at http://www.webcitation.org/6zPQmvOF2)

A Randomized Controlled Feasibility Trial in Behavioral Weight Management for Underserved Postpartum African American Women: The RENEW Study

We aimed to test the feasibility of an in-person behavioral weight-loss intervention for underserved postpartum African American women with overweight or obesity in an urban hospital setting. Participants were randomized to an intervention of a culturally tailored adaptation of the Diabetes Prevention Program or usual care. The primary outcome was program satisfaction. Women who completed the intervention reported higher levels of satisfaction with the program, despite low attendance rates at group meetings. The intervention was not feasible because of these low rates of attendance and high rates of attrition after randomization. Offering the program electronically and off-site for convenience and more psychosocial support for postpartum women with obesity may improve feasibility.

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

ObjectiveOverweight/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. DesignCross-sectional. SettingVeterans Health Administration Medical Center outpatient clinic. SubjectsThe 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). MethodsVeterans referred for weight loss treatment (MOVE!) at VA Connecticut completed self-report questionnaires, and electronic medical records were reviewed. ResultsMean 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. ConclusionsFor 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.

Critical review and meta-analysis of multicomponent behavioral e-health interventions for weight loss.

Multicomponent behavioral e-health interventions are seen as an alternative to in-person treatment for weight loss. However, these estimates may be optimistic at best. This is the first meta-analysis to investigate the relative efficacy of multicomponent behavioral e-health interventions for weight loss against separate groups of active in-person treatment and passive controls (e.g., waitlist, no care, usual care, or placebo group). Forty-seven randomized controlled trials on multicomponent e-health interventions for weight loss in overweight and/or obese adults were included. A random-effects model was used for pooling the effect sizes, which were calculated for weight and behavioral outcomes at posttreatment and follow-up. Standard active treatment was more effective than e-health interventions with respect to weight (g = -0.31, 95% CI [-0.43 to -0.20]). There was a statistically significant, albeit small effect size favoring e-health interventions relative to passive control groups for weight (g = 0.34, 95% CI [0.24 to 0.44]) and behavioral outcomes (g = 0.17, 95% CI [0.07 to 0.27]). Several potential moderator variables were examined and discussed. Overall, the findings raise concerns regarding the current potential of multicomponent behavioral e-health interventions as first-line treatment for weight-loss. Other limitations and possible implications are discussed. (PsycINFO Database Record

Effects of Treatment-Associated Increases in Fruit and Vegetable Intake on the Consumption of Other Food Groups and Weight Through Self-Regulatory Processes.

Increased intake of fruits and vegetables (FV) may be useful for weight loss. This study was designed to evaluate the effects of changes in FV intake on the overall diet and to determine if self-regulation affects the association between changes in FV intake and weight. Women with obesity (N = 74, mean age = 47.7 years) participating in a year-long behavioral weight-loss treatment were assessed regarding changes in consumption of various food groups, physical activity, and eating self-regulation over 6, 12, and 24 months. FV intake change significantly predicted changes in weight and consumption of dairy and bread products and sweets. The only other notable relationships were among changes in sweets, bread, and dairy consumption over 24 months. Over 6, 12, and 24 months, changes in self-regulation significantly mediated the FV intake-weight change relationship. The overall mediation models were significant (R2 values = 0.19, 0.13, and 0.32, respectively). A reciprocal relationship between changes in FV intake and self-regulation also was found. Significant increases in physical activity outputs did not influence weight changes. Findings supported a relationship between FV intake and weight loss occurring through self-regulatory skills. Associations between FV intake and reduced consumption of other food groups provided data useful for improving the architecture of behavioral weight-loss treatments and the foci of medical practitioners' helping methods.

Examination Of The Association Between Values And Physical Activity In A Behavioral Program

Theory-based approaches imply that values may be a construct that influences motivation and adherence to health behavior change. PURPOSE: This study examined the associations between individual values and change in physical activity in adults enrolled in a 6-month behavioral weight loss intervention. METHODS: Baseline data for 67 participants (age = 44.2±9.0 years; body mass index = 32.6±3.9 kg/m2) and 58 participants at 6 months (age = 43.9±9.2 years; body mass index = 32.6±4.0 kg/m2) were analyzed. The 6-month behavioral weight loss intervention included prescribed moderate-to-vigorous physical activity of 150 to 250min/wk. Only participants prescribed physical activity within the intervention were included in the statistical analysis. Assessments at baseline and 6 months included: 1) self-reported leisure-time physical activity, 2) personal values, 3) perception of engaging in physical activity would have on their values. RESULTS: At both baseline and 6 months, the three most frequently identified values were marriage/couples/intimate relationships (75.9%), family (60.3%), and parenting (56.9%). Spearman correlation coefficients were not statistically significant between change in leisure-time physical activity and perception of the impact engaging in a physical activity will have on their values at baseline (range of r’s: -0.029 to 0.154, p’s range: 0.364 to 0.927) and 6 months (range of r’s: -0.018 to 0.098, p’s range: 0.564 to 0.916). DISCUSSION: Self-reported values did not change following participation in a behavioral weight loss intervention. Perceptions of how engagement in physical activity would alter values were also not associated with change in leisure-time physical activity. These results suggest that linking physical activity to values would not impact the magnitude of improvement in leisure-time physical activity within the context of a comprehensive behavioral weight loss intervention. However, this warrants additional investigation to determine if interventions specifically linking values to physical activity would elicit similar effects.

A multimodal investigation of impulsivity as a moderator of the relation between momentary elevations in negative internal states and subsequent dietary lapses

Suboptimal outcomes from behavioral weight loss (BWL) treatments are partially attributable to accumulated instances of non-adherence to dietary prescriptions (i.e., dietary lapses). Results identifying negative internal triggers for dietary lapses are inconsistent, potentially due to individual differences that impact how individuals respond to cues. Impulsivity is one factor that likely influences reactivity to internal states. We examined three dimensions of impulsivity (delay discounting, inhibitory control, and negative urgency) as moderators of the relation between affective and physical states and subsequent dietary lapses at the beginning of BWL. Overweight/obese adults (n = 189) completed behavioral and self-reported measures of impulsivity at baseline of BWL and an ecological momentary assessment (EMA) protocol across the first two weeks of treatment to report on affective/physical states and instances of dietary lapses. Results indicated that baseline negative urgency, but not delay discounting or inhibitory control, was positively associated with overall lapse risk. Moderation analyses indicated that poorer inhibitory control strengthened the relation between momentary increases in stress and subsequent dietary lapse, and higher negative urgency strengthened the relation between increases in loneliness and dietary lapse. Negative urgency also moderated the impact of momentary hunger on subsequent dietary lapse risk in an unexpected direction, such that higher negative urgency weakened the relation between hunger and subsequent lapse. Results lend partial and tentative support for the moderating role of impulsivity on the relation between internal states and lapse likelihood. With replication, the development and testing of personalized treatment components based on baseline impulsivity level may be warranted.

Does mental health influence weight loss in adults with prediabetes? Findings from the VA Diabetes Prevention Program.

Mental illness may impact outcomes from structured behavioral weight loss interventions. This secondary analysis investigated the influence of mental health on weight loss among Veterans with prediabetes enrolled in either an in-person diabetes prevention program (DPP) or the usual care weight management program (MOVE!) designed to help patients achieve weight loss through changes in physical activity and diet. Prediabetes was defined by Hemoglobin A1c between 5.7 and 6.4% or Fasting Plasma Glucose 100-125 mg/dL and no use of antiglycemic medications during the past six months. Veterans Health Administrative data were used to assign Veterans into one of three mental health diagnoses: severe mental illness (SMI), affective disorder (AD) without SMI, or No SMI/No AD. The influence of mental health on weight changes at 6 and 12 months was modeled using linear mixed-effects regression. On average, Veterans with prediabetes (n = 386) were 59 years old (SD = 10.0 years), with a BMI of 34.8 kg/m2 (SD = 5.3 kg/m2) and A1c of 6.0% (SD = 0.2%). The sample consisted of 12% (n = 47), 39% (n = 150), and 49% (n = 189) diagnosed with SMI, AD and No SMI/No AD, respectively. Across interventions, Veterans with SMI lost less weight than those with AD or No SMI/No AD. From baseline to 6 months, weight loss was significantly less for Veterans with SMI (1.53 kg) compared to Veterans with AD (3.85 kg) or No SMI/No AD (3.73 kg). This weight loss trend by mental health diagnosis continued from baseline to 12 months but was no longer statistically significant at 12 months. Weight loss was not clinically or statistically different among Veterans with prediabetes diagnosed with AD or No SMI/No AD. However, Veterans diagnosed with SMI exhibited less weight loss over 6 months than Veterans with AD or No SMI/No AD and though not statistically significant, the trend continued to 12 months, suggesting that SMI may influence weight loss outcomes.

Abstract P338: Adults With Obstructive Sleep Apnea Have Lower Adherence to Weight Loss Behaviors in a Behavioral Weight Loss Intervention

Introduction: Obesity is a primary risk factor for obstructive sleep apnea (OSA), and weight loss is a common recommendation for adults with OSA. However, we previously found that adults with OSA lost less weight than those without OSA during a 12-month behavioral weight loss intervention. The potential mechanisms underlying the blunted weight loss among those with OSA are currently unclear; however, one potential explanation may be lower adherence to the intervention and its prescribed behaviors. Purpose: These analyses examined whether measures of adherence to a behavioral weight loss intervention differed between adults with and without OSA. Methods: The sample was comprised of adults who were overweight or obese (N=114; 50.4±10.5 y, body mass index [BMI]: 34.0±4.6 kg/m 2 ; 90.4% female, 82.5% white) who participated in a 12-mo behavioral weight loss intervention study. Participants wore a home sleep testing device (ResMed ApneaLink Plus) for one night at baseline (BL), 6 mo (6M), and 12 mo (12M). Those with an apnea-hypopnea index ≥ 5 were categorized as having OSA. Adherence to the intervention was assessed by: 1) attendance at group intervention sessions over 12 mo; 2) frequency of meeting daily caloric intake goals over 12 mo; 3) objectively-measured changes from BL in physical activity (steps/day, sedentary time, moderate-vigorous physical activity [MVPA]). Linear mixed models estimated the impact of OSA on these measures of intervention adherence following adjustment for sex, age, race, marital status, smoking status, and baseline BMI, while considering participant to be a random effect. Results: About half (52%) of the participants had OSA at BL, while 41 % had OSA at 6M. Attendance at group sessions did not differ between those with and without OSA over 12 mo (74.5 vs. 75.7%; P=.72). However, adults with OSA met their caloric intake goal less frequently than those without OSA (25.2 vs. 34.8%; P=.006), and adults with OSA increased their steps/day (+378.3 vs. 1060.1; P=.047) and MVPA min/day (+2.1 vs. +6.4; P=.056) less than those without OSA. Reductions in sedentary behavior (min/day) did not differ between those with and without OSA (-7.1 vs. -9.1; P=.81). Conclusions: These data suggest that the blunted weight loss observed among adults with OSA may be at least partially attributable to lower levels of adherence to prescribed goals for caloric intake and physical activity. Additional strategies (e.g., OSA screening and treatment referral, supplemental sessions on diet and MVPA) may be needed to achieve improved adherence to the lifestyle behaviors that lead to weight loss among adults with OSA.

Are individuals with loss-of-control eating more prone to dietary lapse in behavioural weight loss treatment? An ecological momentary assessment study.

Individuals with overweight/obesity and loss-of-control eating (LOC) may experience poorer outcomes from behavioural weight loss due to reactivity to internal (e.g., affective and physical) states that impact treatment adherence (e.g., dietary lapses). This study examined (a) whether the presence of LOC increased risk for dietary lapses and (b) the moderating role of LOC on the relation between internal states and dietary lapses. Individuals (n=189) with overweight and obesity completed ecological momentary assessment early in behavioural weight loss. LOC was positively associated with dietary lapse. LOC did not moderate the relation between momentary changes in internal states and dietary lapses. However, the effect of average levels of internal states on lapses was attenuated for those with LOC. Results suggest that those with LOC are at higher risk of dietary lapse, whereas elevated average levels of internal states may contribute to early inadherence for those without LOC.

Dynamic fMRI networks predict success in a behavioral weight loss program among older adults

More than one-third of adults in the United States are obese, with a higher prevalence among older adults. Obesity among older adults is a major cause of physical dysfunction, hypertension, diabetes, and coronary heart diseases. Many people who engage in lifestyle weight loss interventions fail to reach targeted goals for weight loss, and most will regain what was lost within 1–2 years following cessation of treatment. This variability in treatment efficacy suggests that there are important phenotypes predictive of success with intentional weight loss that could lead to tailored treatment regimen, an idea that is consistent with the concept of precision-based medicine. Although the identification of biochemical and metabolic phenotypes are one potential direction of research, neurobiological measures may prove useful as substantial behavioral change is necessary to achieve success in a lifestyle intervention. In the present study, we use dynamic brain networks from functional magnetic resonance imaging (fMRI) data to prospectively identify individuals most likely to succeed in a behavioral weight loss intervention. Brain imaging was performed in overweight or obese older adults (age: 65–79 years) who participated in an 18-month lifestyle weight loss intervention. Machine learning and functional brain networks were combined to produce multivariate prediction models. The prediction accuracy exceeded 95%, suggesting that there exists a consistent pattern of connectivity which correctly predicts success with weight loss at the individual level. Connectivity patterns that contributed to the prediction consisted of complex multivariate network components that substantially overlapped with known brain networks that are associated with behavior emergence, self-regulation, body awareness, and the sensory features of food. Future work on independent datasets and diverse populations is needed to corroborate our findings. Additionally, we believe that efforts can begin to examine whether these models have clinical utility in tailoring treatment.

A marginalized two-part model with heterogeneous variance for semicontinuous data.

Semicontinuous data, characterized by a point mass at zero followed by a positive, continuous distribution, arise frequently in medical research. These data are typically analyzed using two-part mixtures that separately model the probability of incurring a positive outcome and the distribution of positive values among those who incur them. In such a conditional specification, however, standard two-part models do not provide a marginal interpretation of covariate effects on the overall population. We have previously proposed a marginalized two-part model that yields more interpretable effect estimates by parameterizing the model in terms of the marginal mean. In the original formulation, a constant variance was assumed for the positive values. We now extend this model to a more general framework by allowing non-constant variance to be explicitly modeled as a function of covariates, and incorporate this variance into two flexible distributional assumptions, log-skew-normal and generalized gamma, both of which take the log-normal distribution as a special case. Using simulation studies, we compare the performance of each of these models with respect to bias, coverage, and efficiency. We illustrate the proposed modeling framework by evaluating the effect of a behavioral weight loss intervention on health care expenditures in the Veterans Affairs health system.