Life events and stress among young adults in weight gain prevention trial.

OBJECTIVE: Young adults (YAs) are at high risk for weight gain and show high variability in treatment response. Life events and high perceived stress are common in YAs and could drive less favorable outcomes. The goal was to examine whether life events and stress were related to program engagement and weight outcomes in a weight gain prevention trial for YAs. METHOD: Secondary analysis from the Study of Novel Approaches to Weight Gain Prevention (SNAP), a randomized clinical trial (N = 599, 18-35 years, BMI 21-30 kg/m²). Both intervention arms received 10 in-person sessions over 4 months, with long-term contact via web and SMS. Participants completed the CARDIA life events survey and Cohen Perceived Stress Scale-4 at 0 and 4 months; weight was objectively measured at 0, 4 months, and 1, 2, 3, and 4 years. RESULTS: Participants who experienced more life events prior to study entry had lower session attendance (p < .01) and retention (p < .01), although no differences in weight outcomes were observed (p = .39). Baseline perceived stress followed a similar pattern. Participants who experienced more life events and higher perceived stress during the initial in-person program (0-4 months) appeared to experience less favorable weight outcomes long-term (p = .05 for life events, p = .04 for stress). Very few associations differed by treatment arm. CONCLUSIONS: Experiencing more life events and stress was negatively associated with program engagement and may impair long-term weight outcomes for YAs. Future work should consider identifying YAs at highest risk and tailoring interventions to better meet their needs. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Efficacy of a Commercial Weight Management Program Compared With a Do-It-Yourself Approach: A Randomized Clinical Trial.

Importance: Given the prevalence of obesity, accessible and effective treatment options are needed to manage obesity and its comorbid conditions. Commercial weight management programs are a potential solution to the lack of available treatment, providing greater access at lower cost than clinic-based approaches, but few commercial programs have been rigorously evaluated. Objective: To compare the differences in weight change between individuals randomly assigned to a commercial weight management program and those randomly assigned to a do-it-yourself (DIY) approach. Design, Setting, and Participants: This 1-year, randomized clinical trial conducted in the United States, Canada, and United Kingdom between June 19, 2018, and November 30, 2019, enrolled 373 adults aged 18 to 75 years with a body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) of 25 to 45. Assessors were blinded to treatment conditions. Interventions: A widely available commercial weight management program that included reduced requirements for dietary self-monitoring and recommendations for a variety of DIY approaches to weight loss. Main Outcomes and Measures: The primary outcomes were the difference in weight change between the 2 groups at 3 and 12 months. The a priori hypothesis was that the commercial program would result in greater weight loss than the DIY approach at 3 and 12 months. Analyses were performed on an intention-to-treat basis. Results: The study include 373 participants (272 women [72.9%]; mean [SD] BMI, 33.8 [5.2]; 77 [20.6%] aged 18-34 years, 74 [19.8%] aged 35-43 years, 82 [22.0%] aged 44-52 years, and 140 [37.5%] aged 53-75 years). At 12 months, retention rates were 88.8% (166 of 187) for the commercial weight management program group and 95.7% (178 of 186) for the DIY group. At 3 months, participants in the commercial program had a mean (SD) weight loss of -3.8 (4.1) kg vs -1.8 (3.7) kg among those in the DIY group. At 12 months, participants in the commercial program had a mean (SD) weight loss of -4.4 (7.3) kg vs -1.7 (7.3) kg among those in the DIY group. The mean difference between groups was -2.0 kg (97.5% CI, -2.9 to -1.1 kg) at 3 months (P < .001) and -2.6 kg (97.5% CI, -4.3 to -0.8 kg) at 12 months (P < .001). A greater percentage of participants in the commercial program group than participants in the DIY group achieved loss of 5% of body weight at both 3 months (40.7% [72 of 177] vs 18.6% [34 of 183]) and 12 months (42.8% [71 of 166] vs 24.7% [44 of 178]). Conclusions and Relevance: Adults randomly assigned to a commercial weight management program with reduced requirements for dietary self-monitoring lost more weight and were more likely to achieve weight loss of 5% at 3 and 12 months than adults following a DIY approach. This study contributes data on the efficacy of commercial weight management programs and DIY weight management approaches. Trial Registration: ClinicalTrials.gov Identifier: NCT03571893.

Behavioral weight loss in emerging adults: Design and rationale for the Richmond Emerging Adults Choosing Health (REACH) randomized clinical trial.

BACKGROUND: In the U.S., over 40% of 18-25 year olds meet criteria for overweight or obesity. Yet, no large-scale trials have targeted this age group for behavioral weight loss (BWL). Formative data revealed that existing BWL programs do not meet their unique needs and identified motivation as a fundamental barrier for weight management. The goal of the Richmond Emerging Adults Choosing Health (REACH) trial was to test the efficacy of two mHealth lifestyle interventions specifically focused on enhancing motivation, relative to adapted standard. METHODS: Participants (N = 381, 18-25 years, body mass index 25-45 kg/m2) will be randomized to 1) adapted BWL (aBWL), 2) aBWL + self-determination theory (aBWL+SDT), or 3) aBWL + behavioral economics (aBWL+BE). All arms will receive a 6-month intervention, delivered via one group session and one individual session, followed by an mHealth platform. Assessments will occur at baseline, 3-months, 6-months (post-treatment) and 12-months (following a no-contact period). The primary aim is to compare weight loss outcomes at 6 months. Secondary aims include changes at 6-months in physical and behavioral cardiometabolic risk factors, as well as psychosocial measures. We will also explore weight loss maintenance, change in hypothesized mediators, and moderators of treatment response. DISCUSSION: REACH is the first large-scale BWL trial designed specifically for emerging adults. Further, it will be the first trial to compare a lifestyle intervention grounded in self-determination theory to one rooted in behavioral economics. If clinically significant reductions in adiposity are achieved, findings could inform a scalable treatment model to meet the needs of this vulnerable population. TRIAL REGISTRATION: NCT02736981.

Promoting physical activity in young adult cancer survivors using mHealth and adaptive tailored feedback strategies: Design of the Improving Physical Activity after Cancer Treatment (IMPACT) randomized controlled trial.

INTRODUCTION: Despite the health benefits of physical activity for cancer survivors, nearly 60% of young adult cancer survivors (YACS) are physically inactive. Few physical activity interventions have been designed specifically for YACS. PURPOSE: To describe the rationale and design of the IMPACT (IMproving Physical Activity after Cancer Treatment) trial, which tests the efficacy of a theory-based, mobile physical activity intervention for YACS. METHODS: A total of 280 physically inactive YACS (diagnosed at ages 18-39) will be randomized to a self-help control or intervention condition. All participants will receive an activity tracker and companion mobile app, cellular-enabled scale, individual videochat session, and access to a Facebook group. Intervention participants will also receive a 6-month mobile intervention based on social cognitive theory, which targets improvements in behavioral capability, self-regulation, self-efficacy, and social support, and incorporates self-regulation strategies and behavior change techniques. The program includes: behavioral lessons; adaptive goal-setting in response to individuals' changing activity patterns; tailored feedback based on objective data and self-report measures; tailored text messages; and Facebook prompts encouraging peer support. Assessments occur at baseline, 3, 6, and 12 months. The primary outcome is total physical activity min/week at 6 months (assessed via accelerometry); secondary outcomes include total physical activity at 12 months, sedentary behavior, weight, and psychosocial measures. CONCLUSIONS: IMPACT uniquely focuses on physical activity in YACS using an automated tailored mHealth program. Study findings could result in a high-reach, physical activity intervention for YACS that has potential to be adopted on a larger scale and reduce cancer-related morbidity. ClinicalTrials.gov Identifier: NCT03569605.

Examination of a partial dietary self-monitoring approach for behavioral weight management.

INTRODUCTION: Dietary self-monitoring in behavioral weight loss programmes traditionally involves keeping track of all foods and beverages to achieve a calorie deficit. While effective, adherence declines over time. WW™ (formerly Weight Watchers), a widely available commercial weight management programme, sought to pilot an approach that permitted participants to consume over 200 foods without monitoring them. METHODS: The current study used a pre-post evaluation design with anthropometric, psychosocial and physical health assessments at baseline, 3 and 6 months. RESULTS: Participants (N = 152) were, on average, 48.4 (±12.3) years old, with body mass index (BMI) of 32.8 (±4.8) m/kg2 and 94% female. Mean weight loss was 6.97 + 5.55 kg or 7.9 ± 6.1% of initial body weight (ps < .0001) at 6 months. One third (32.6%) of the sample lost 10% or more of initial body weight. Significant improvements in hunger, cravings, happiness, sleep, quality of life, aerobic stamina, flexibility and blood pressure were observed. Attendance at group meetings, as well as decreases in hunger, and fast food cravings from baseline to 3 months were associated with achieving 10% weight loss at 6 months (p < .01). CONCLUSIONS: Using an approach that does not require self-monitoring of all foods and beverages produced significant weight losses and other physical and psychosocial improvements.

Engagement and Weight Loss in a Web and Mobile Program for Low-Income Postpartum Women: Fit Moms/Mamás Activas.

Internet-based weight loss programs can be effective in promoting weight loss and are less-intensive than traditional face-to-face approaches, which may provide more flexibility for postpartum, low-income women to engage in such programs. Few studies have examined patterns of engagement in internet-based programs for this population. This article used data from the internet-based Fit Moms/Mamás Activas intervention, a 12-month cluster randomized controlled trial that was effective in promoting postpartum weight loss among low-income, predominantly Hispanic women. The overall objectives of this study were to (1) characterize patterns of engagement with the Fit Moms/Mamás Activas website among intervention participants and (2) explore associations between engagement and 12-month weight loss outcomes among study completers (87.4%). A number of engagement variables were calculated for each participant, including website logins; time spent on the website; number of posts to the "Discussion Forum;" number of days tracking weight, diet, and physical activity; number of page visits to various website components; and number of in-person visits attended. The average number of logins was 70.74 (approximately once weekly), and average total time spent on the website was 185.35 minutes (approximately 3 hours) over 1 year. Self-monitoring ("Web Diary") and social support ("Discussion Forum") were the most frequently visited components of the website, and more frequent engagement with these components, as well as greater attendance at in-person group sessions, predicted greater percent weight loss at 12 months. Interventions highlighting these features may be particularly effective for weight loss in this population.

Dietary outcomes within the study of novel approaches to weight gain prevention (SNAP) randomized controlled trial.

BACKGROUND: Young adults (YA) are at high-risk for unhealthy dietary behaviors and weight gain. The Study of Novel Approaches to Weight Gain Prevention (SNAP) Trial demonstrated that two self-regulation approaches were effective in reducing weight gain over 2 years compared with control. The goal of this analysis was to examine effects of intervention on dietary outcomes and the association of diet changes with weight change. METHODS: Participants were 599 YA, age 18-35 years, BMI 21.0-30.0 kg/m2 (27.4 ± 4.4 years; 25.4 ± 2.6 kg/m2; 22% men; 73% non-Hispanic White), who were recruited in Providence, RI and Chapel Hill, NC and randomized to self-regulation with Small Changes (SC), self-regulation with Large Changes (LC) or Control (C). SC and LC emphasized frequent self-weighing to cue behavior changes (small daily changes vs. periodic large changes) and targeted high-risk dietary behaviors. Diet and weight were assessed at baseline, 4 months and 2 years. RESULTS: LC and SC had greater decreases in energy intake than C at 4 months but not 2 years. LC had the greatest changes in percent calories from fat at 4 months, but differences were attenuated at 2 years. No differences in diet quality were observed. Across conditions, increased total energy consumption, fast food, meals away from home, and binge drinking, and decreased dietary quality and breakfast consumption were all associated with weight gain at 2 years. CONCLUSIONS: This study suggests the need to strengthen interventions to produce longer term changes in dietary intake and helps to identify specific behaviors associated with weight gain over time in young adults. TRIAL REGISTRATION: Clinicaltrials.gov # NCT01183689 , registered August 18, 2010.

Eating pathology and psychological outcomes in young adults in self-regulation interventions using daily self-weighing.

OBJECTIVE: Self-regulation interventions encouraging daily weighing prevent weight gain in young adults; however, concerns have been raised that such interventions may have undesirable effects on eating pathology, depression, and health-related quality of life (HRQL). The present study examined whether self-regulation interventions and self-weighing frequency were associated with these indices in normal weight individuals and those with overweight or obesity. METHODS: Young adults (n = 599), 18-35 years with a body mass index (BMI) 21.0-30.9 kg/m² were randomized to control, self-regulation with small changes (SC) or self-regulation with large changes (LC). Interventions taught frequent self-weighing to guide behavioral changes. SC prescribed daily small decreases in intake and increases in physical activity. LC prescribed a 5- to 10-lb weight loss to buffer against anticipated gains. Psychological indices were assessed at baseline and periodically over 2 years of follow-up. RESULTS: There was no evidence that the interventions increased depressive symptoms or compensatory behaviors or decreased HRQL relative to control. LC increased flexible and rigid control and SC decreased disinhibition. Results did not differ by weight status with the exception of rigid control; here, differences between LC and the other conditions were smaller among those with BMI ≥ 25. Greater self-weighing frequency over time was associated with increases in flexible and rigid control, dietary restraint, and improvements in HRQL. CONCLUSIONS: The self-regulation interventions and increases in self-weighing had no untoward effects. Encouraging weight gain prevention in young adults through frequent weighing and self-regulation appears to be safe for normal weight young adults and those with overweight. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Randomized trial comparing group size of periodic in-person sessions in a remotely delivered weight loss intervention.

BACKGROUND: Few randomized studies have examined differential effects of group size in behavioral weight control, especially in hybrid programs that include Internet treatment approaches. METHODS: Randomized controlled trial (n = 195) comparing a 4 month hybrid internet weight loss program coupled with monthly face to face groups of 100 persons (Large Group, LG; 1 group) or to the same approach with monthly groups of 20 persons (Small Group, SG; 4 groups). Repeated-measures mixed-model analysis with age and race as covariates were used to estimate primary (weight) and secondary outcomes, and to test group differences in change over time. RESULTS: The sample was 46.3 years old ±10.4, 90.3% female, and 51.9% non-white, with BMI 37.9 ± 8.4 kg/m2. Participants in the LG were more likely to return for the 4-month assessment visit than those in the SG (p = 0.04). Participants randomized to both the LG and SG conditions experienced significant WL over time (no between group difference: -4.1 kg and -3.7 kg, respectively) and weight loss was positively associated with attendance at monthly meetings and logins to the website. Satisfaction with the program was high and similar in both groups (94.4% reported that they were "satisfied" or "very satisfied"). CONCLUSIONS: Using a hybrid approach of in-person and online weight loss interventions may be an effective way to reach larger and more diverse populations. Delivering the face to face component of the intervention in groups larger than those traditionally delivered (20-25 people) could increase the cost-effectiveness of group-based behavioral weight loss interventions. CLINICAL TRIALS REGISTRATION NUMBER: NCT01615471 . Registered June 6, 2012. Registered retrospectively.

Acculturation Influences Postpartum Eating, Activity, and Weight Retention in Low-Income Hispanic Women.

BACKGROUND: Low-income Hispanic women experience elevated rates of high postpartum weight retention (PPWR), which is an independent risk factor for lifetime obesity. Sociocultural factors might play an important role among Hispanic women; however, very few studies have examined this association. OBJECTIVE: The purpose of our study was to examine the associations between acculturation and maternal diet, physical activity, and PPWR. DESIGN: This is a cross-sectional study of baseline data from 282 Hispanic women participating in the FitMoms/Mamás Activas study, a randomized controlled trial examining the impact of primarily an internet-based weight control program, in reducing PPWR among low-income women. We performed multivariable linear regression to examine the association of acculturation with diet quality, physical activity, and PPWR at study entry. RESULTS: A total of 213 (76%) women had acculturation scores reflecting Mexican orientation or bicultural orientation, whereas 69 (24%) had scores that represented assimilation to Anglo culture. Women who were more acculturated had lower intakes of fruits and vegetables, lower HEI scores, and lower physical activity levels than women who were less acculturated (p < 0.05). We found an association between acculturation and PPWR in that for every 1-unit increase in acculturation score, PPWR increased, on average, by 0.80 kg. CONCLUSION: Higher acculturation was associated with poorer diet and physical activity behaviors and greater PPWR.

Effect of an Internet-Based Program on Weight Loss for Low-Income Postpartum Women: A Randomized Clinical Trial.

Importance: Postpartum weight retention increases lifetime risk of obesity and related morbidity. Few effective interventions exist for multicultural, low-income women. Objective: To test whether an internet-based weight loss program in addition to the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC program) for low-income postpartum women could produce greater weight loss than the WIC program alone over 12 months. Design, Setting, and Participants: A 12-month, cluster randomized, assessor-blind, clinical trial enrolling 371 adult postpartum women at 12 clinics in WIC programs from the California central coast between July 2011 and May 2015 with data collection completed in May 2016. Interventions: Clinics were randomized to the WIC program (standard care group) or the WIC program plus a 12-month primarily internet-based weight loss program (intervention group), including a website with weekly lessons, web diary, instructional videos, computerized feedback, text messages, and monthly face-to-face groups at the WIC clinics. Main Outcomes and Measures: The primary outcome was weight change over 12 months, based on measurements at baseline, 6 months, and 12 months. Secondary outcomes included proportion returning to preconception weight and changes in physical activity and diet. Results: Participants included 371 women (mean age, 28.1 years; Hispanic, 81.6%; mean weight above prepregnancy weight, 7.8 kg; mean months post partum, 5.2 months) randomized to the intervention group (n = 174) or standard care group (n = 197); 89.2% of participants completed the study. The intervention group produced greater mean 12-month weight loss compared with the standard care group (3.2 kg in the intervention group vs 0.9 kg in standard care group, P < .001; difference, 2.3 kg (95% CI, 1.1 to 3.5). More participants in the intervention group than the standard care group returned to preconception weight by 12 months (32.8% in the intervention group vs 18.6% in the standard care group, P < .001; difference, 14.2 percentage points [95% CI, 4.7 to 23.5]). The intervention group and standard care group did not significantly differ in 12-month changes in physical activity (mean [95% CI]: -7.8 min/d [-16.1 to 0.4] in the intervention group vs -7.2 min/d [-14.6 to 0.3] in the standard care group; difference, -0.7 min/d [95% CI, -42.0 to 10.6], P = .76), calorie intake (mean [95% CI]: -298 kcal/d [-423 to -174] in the intervention group vs -144 kcal/d [-257 to -32] in the standard care group; difference, -154 kcal/d [-325 to 17], P = .06), or incidences of injury (16 in the intervention group vs 16 in the standard care group) or low breastmilk supply from baseline to month 6 (21 of 61 participants in the intervention group vs 23 of 72 participants in the standard care group) and from month 6 to 12 (13 of 32 participants in the intervention group vs 14 of 37 participants in the standard care group). Conclusions and Relevance: Among low-income postpartum women, an internet-based weight loss program in addition to the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC program) compared with the WIC program alone resulted in a statistically significant greater weight loss over 12 months. Further research is needed to determine program and cost-effectiveness as part of the WIC program. Trial Registration: clinicaltrials.gov Identifier: NCT01408147.

The Gestational Diabetes Management System (GooDMomS): development, feasibility and lessons learned from a patient-informed, web-based pregnancy and postpartum lifestyle intervention.

BACKGROUND: Gestational diabetes mellitus (GDM) contributes to the epidemic of diabetes and obesity in mothers and their offspring. The primary objective of this pilot study was to: 1) refine the GDM Management System (GooDMomS), a web-based pregnancy and postpartum behavioral intervention and 2) assess the feasibility of the intervention. METHODS: In phase 1, ten semi-structured interviews were conducted with women experiencing current or recent GDM mellitus GDM to garner pilot data on the web based intervention interface, content, and to solicit recommendations from women about refinements to enhance the GooDMomS intervention site. Interviews were audiotaped, transcribed and independently reviewed to identify major themes with Atlas.ti v7.0. In phase 2, a single-arm feasibility study was conducted and 23 participants were enrolled in the GooDMomS program. Participants received web lessons, self-tracking of weight and glucose, automated feedback and access to a message board for peer support. The primary outcome was feasibility, including recruitment and retention and acceptability. Secondary outcomes included the proportion of women whose gestational weight gain (GWG) was within the Institute of Medicine (IOM) guidelines and who were able to return to their pre-pregnancy weight after delivery. RESULTS: Comments from semi-structured interviews focused on: 1) usability of the on-line self-monitoring diary and tracking system, 2) access to a safe, reliable social network for peer support and 3) ability of prenatal clinicians to access the on-line diary for clinical management. Overall, 21 (91 %) completed the pregnancy phase. 15/21 (71 %) of participants were within the Institute of Medicine (IOM) guidelines for GWG. Sixteen (70 %) completed the postpartum phase. 7/16 (43 %) and 9/16 (56 %) of participants returned to their pre-pregnancy weight at 6 and 30 weeks postpartum, respectively. CONCLUSIONS: This study documents the feasibility of the GooDMomS program. The results can have implications for web technology in perinatal care and inform the current care paradigm for women with GDM. Findings are supportive of further research with recruitment of a larger sample of participants and comparison of the outcomes with the intervention and standard care. TRIAL REGISTRATION: The study was registered at ClinicalTrials.gov on May 15, 2012 under protocol no. NCT01600534 .

The Effect of Self-Efficacy on Behavior and Weight in a Behavioral Weight-Loss Intervention.

OBJECTIVE: To determine whether eating self-efficacy (ESE) and physical activity self-efficacy (PASE) are predictive of dietary intake, physical activity, and weight change within a behavioral weight-loss intervention, and whether dietary intake and physical activity mediate relationships between self-efficacy and weight change. METHOD: The study sample included 246 participants from a randomized trial with complete data on study variables at 12 months. ESE, PASE, calories consumed, minutes of moderate-to-vigorous physical activity (MVPA), and weight were measured at baseline, 6, and 12 months. RESULTS: ESE at baseline was associated with 12-month percent weight loss (PWL), and was mediated by average calories consumed at 6 and 12 months. Change in ESE from baseline to 6 months was associated with calories consumed at 12 months and 12-month percent weight loss, but the mediated relationship was not significant. Baseline PASE was not associated with average MVPA at 6 and 12 months or 12-month PWL, but change in PASE from baseline to 6 months was associated with 12-month PWL through its effect on MVPA at 12 months. CONCLUSION: Increases in ESE and PASE during the active phase of the intervention are predictive of dietary intake, physical activity and weight loss at later points, but further research should include explorations of the reciprocal relationship between behavior and self-efficacy to better inform intervention strategies that target self-efficacy and promote behavior change. (PsycINFO Database Record

Innovative Self-Regulation Strategies to Reduce Weight Gain in Young Adults: The Study of Novel Approaches to Weight Gain Prevention (SNAP) Randomized Clinical Trial.

IMPORTANCE: Weight gain occurs commonly in young adults and has adverse effects on health. OBJECTIVE: To compare 2 self-regulation interventions vs control in reducing weight gain in young adults over a mean follow-up of 3 years. DESIGN, SETTING, AND PARTICIPANTS: Randomized clinical trial in 2 academic settings of 599 participants aged 18 to 35 years with body mass index (BMI, calculated as weight in kilograms divided by height in meters squared) of 21.0 to 30.0, recruited via mailings and emails from August 2010 to February 2012. Data were analyzed from January 2015 to January 2016. INTERVENTIONS: Participants were randomized to control, self-regulation plus small changes, or self-regulation plus large changes. Both interventions focused on frequent self-weighing to cue behavior changes. "Small changes" taught participants to reduce intake and increase activity, both by approximately 100 calories per day. "Large changes" focused on losing 2.3 to 4.5 kg initially to buffer against expected weight gain. MAIN OUTCOMES AND MEASURES: Changes in weight from baseline over mean follow-up of 3 years. Secondary outcomes included proportion gaining at least 0.45 kg from baseline, proportion developing obesity (BMI, ≥30.0), and weight change baseline to 2 years. RESULTS: Among the 599 participants (22% men; 27% minority; mean [SD] age, 27.7 [4.4] years; mean [SD] BMI, 25.4 [2.6]), mean (SE) weight changes over a mean follow-up of 3 years were 0.26 (0.22), -0.56 (0.22), and -2.37 (0.22) kg in the control, small-changes, and large-changes groups, respectively (P < .001). Differences among all 3 groups were significant (large changes vs control, P < .001; small changes vs control, P = .02; large changes vs small changes, P < .001). On secondary outcomes, both interventions significantly reduced incidence of obesity relative to control (mean [SE], 8.6% [2.0%], 7.9% [2.0%], and 16.9% [2.7%] in the large-changes, small-changes, and control groups, respectively; P = .02 for large changes vs control and P = .002 for small changes vs control); a smaller percentage of participants in the large-changes group gained 0.45 kg or more (mean [SE], 23.6% [2.8%], 32.5% [3.8%], and 40.8% [4.4%], respectively; P < .001 vs control and P = .02 vs small changes) and weight change from baseline to 2 years was greater in control than in small or large changes (mean [SE], 0.54 [0.33], -0.77 [0.33], and -1.50 [0.34] kg, respectively; P = .02 vs small changes and P < .001 vs large changes). CONCLUSIONS AND RELEVANCE: Self-regulation with large or small changes both reduced weight gain in young adults over 3 years relative to control, but the large-changes intervention was more effective. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01183689.