Low Intensity Weight Loss for Young Adults: Autonomous vs. Extrinsic Motivation

描述（由申请人提供）：在18-25岁的人群中，有40%的人超重或肥胖，但这一人群在标准行为减肥（BWL）计划中的代表性也明显不足，迄今为止，还没有针对这一年龄组减肥的完全有效的试验。对这一年龄组进行的形成性研究表明，现有的体重控制计划不能满足他们的独特需求，并且还确定缺乏动力是体重管理的根本障碍。本提案的主要目的是测试两种新颖的、低强度的基于网络的减肥方法的相对功效，这些方法特别关注于增强动机，相对于标准的基于网络的计划。我们最近对这两种方法进行了试点测试，结果令人鼓舞。这两个为期3个月的干预项目都包括一个单独的小组会议，随后是一个每周一次的网络课程，一个自我监控平台和个性化反馈。一个项目植根于自我决定理论，旨在通过在治疗项目中提供各种个人选择，强调行为目标和每周反馈的自主性，促进内在动机和自主自我调节。另一种干预以学习理论和行为经济学原理为基础，并为实现自我监控目标提供小额财政激励；此外，达到临床显著减肥效果的参与者还可以参加抽奖活动，以获得额外的金钱奖励。这两种方法的初步数据都很有前景——参与者的参与度和保持度都很高，并且在3个月后达到了临床意义上的显著体重减轻（ITT=自主激励计划中的4.8%和外在激励计划中的8.8%）。此外，在没有任何额外接触的情况下，体重在6个月时保持下降（分别为5.1%和10.1%）。我们建议进行一项三组随机对照试验，以测试这些新方法在高危人群中减肥的长期疗效。参与者将是381名18-25岁的年轻人，体重指数（BMI）为25-45 kg/m2，他们将被随机分配到3组中的1组：1)标准网络BWL （Web), 2)网络+自主动机（Web+Aut），或3）网络+外在动机（Web+Ext）。所有兵种将接受为期6个月的项目，随后是为期6个月的无接触随访期。动机将在第2周和第2、4、6个月进行评估。体重和次要结局的评估将在0、3、6和12个月进行。我们将在6个月时比较所有三个组的治疗效果，并在6至12个月期间比较各组的减肥维持情况。我们还将检查与我们的理论框架（即自主动机，外在动机）一致的治疗结果的中介。我们假设，与Web相比，Web+Aut和Web+Ext条件将在6个月时产生更大的体重减轻和次要结局的改善。我们进一步假设，相对于Web+Aut， Web+Ext将在6个月时实现更大的体重减轻和次要预后改善。

DESCRIPTION (provided by applicant): Forty percent of 18-25 year olds are overweight or obese, yet this population is also markedly under- represented in standard behavioral weight loss (BWL) programs and to date, no fully powered trials exist which target this age group for weight loss. Formative work conducted with this age group revealed that existing BWL programs do not meet their unique needs, and also identified lack of motivation as a fundamental barrier for weight management. The primary aim of this proposal is to test the relative efficacy of two novel, low intensity web-based approaches to weight loss in this age group that are specifically focused on enhancing motivation, relative to a standard web-based program. We recently pilot tested these two approaches with promising results. Both 3-month intervention programs consisted of a single group based session, followed by a web- based program with weekly lessons, a self-monitoring platform and personalized feedback. One program was rooted in Self-Determination Theory and designed to facilitate intrinsic motivation and promote autonomous self-regulation by offering a variety of personal choices in the treatment program and emphasizing autonomy around behavioral goals and in weekly feedback. The other intervention was grounded in learning theory and principles of behavioral economics, and offered small financial incentives for meeting self-monitoring goals; further, participants achieving a clinically significant weight loss were entered into a raffle for additionl monetary incentives. Preliminary data for both approaches are quite promising - engagement and retention were strong, and participants achieved clinically significant weight losses at 3 months (ITT=4.8% in the Autonomous Motivation program and 8.8% in the Extrinsic Motivation program). Moreover, weight losses were maintained at 6 months without any additional contact (5.1% and 10.1%, respectively). We propose a 3-arm randomized controlled trial to test the longer-term efficacy of these novel approaches to weight loss in this high risk population. Participants will be 381 young adults, 18-25 years, with a body mass index (BMI) of 25-45 kg/m2, who will be randomized to 1 of 3 arms: 1) Standard Web BWL (Web), 2) Web + Autonomous Motivation (Web+Aut), or 3) Web + Extrinsic Motivation (Web+Ext). All arms will receive a 6-month program followed by a 6-month no-contact follow-up period. Motivation will be assessed at week 2 and months 2, 4, and 6. Assessments of weight and secondary outcomes will occur at 0, 3, 6, and 12 months. We will compare treatment effects across all three arms at 6 months, and compare arms on weight loss maintenance from 6 to 12 months. We will also examine mediators of treatment outcomes consistent with our theoretical framework (i.e. autonomous motivation, extrinsic motivation). We hypothesize that the Web+Aut and the Web+Ext conditions will produce greater weight loss and improvement in secondary outcomes at 6 months, compared with Web. We further hypothesize that Web+Ext will achieve greater weight loss and improvement in secondary outcomes at 6 months, relative to Web+Aut.