Evaluating a Remotely Delivered Plant-Based Behavioral Weight Loss Treatment

Study Overview
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Brief Summary
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Many individuals do not achieve clinically significant weight loss following traditional lifestyle modification interventions, potentially because weight loss is dependent upon calorie tracking compliance (to achieve calorie prescriptions), which decreases over time for most. By contrast, non-energy-restricted whole food plant-based diets (WFPBD) have been demonstrated to promote clinically significant weight loss even without calorie prescriptions. The present pilot trial represents the first, to the knowledge of our study team, to empirically test a remotely delivered WFPBD behavioral weight loss intervention for adults with overweight or obesity. Over 12-weeks, participants (N = 21) will follow a non-energy-restricted WFPBD and received nutritional counseling and behavioral weight loss intervention. Participation will occur in two phases (Phase 1: n = 7; Phase 2: n = 14), between which iterative changes to the intervention will be made. Assessments will occur at baseline, mid-treatment, post-treatment, and 3-month follow-up. Data will be analyzed using an intent-to-treat approach. The primary aims of the study will be to assess retention feasibility and acceptability. The secondary aims will be to evaluate the preliminary effectiveness of the intervention on: (1) percent weight loss; (2) dietary intake (i.e., increased intake of low-fat plant-based whole foods and decreased in intake of processed foods and animal products); and (3) waist circumference. The exploratory aims will be to evaluate the preliminary effectiveness of the intervention on physical- and mental health-related quality of life, and to examine potential moderators of treatment success (plant-based diet history, internal disinhibition, social support vs. social sabotage, self-compassion, and psychological flexibility).

Official Title
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A Pilot Study of a Novel Ad Libitum Plant-Based Behavioral Weight Loss Treatment

Conditions
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Obesity, Overweight

Intervention / Treatment
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* Behavioral: Whole Food Plant-Based Behavioral Weight Loss Treatment


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Aged 18-75 Current BMI ≥ 25 kg/m2 Reporting a desire to lose weight Have at-home internet access Proficiency in speaking, reading, and writing English Willing to consume a whole foods plant-based diet for the study duration Exclusion Criteria: Use of medications for weight loss Recent weight loss (≥5% weight loss in prior 3-months) Current or planned pregnancy within the study period History of bariatric surgery Currently following a low-fat plant-based diet Diagnosis of a serious medical condition influencing weight, appetite, or eating behavior Diagnosis of a serious psychiatric condition that may influence weight, appetite, or eating behavior Current substance use disorder Participation in a concurrent weight loss program Planning on quitting smoking over the intervention period (if current smoker) Eating pathology (lifetime history of an eating disorder, ≥ 9 binge eating episodes in the past 3 months, or > 5 compensatory episodes in the past 3 months)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Intervention<br>All participants will be prescribed a non-energy-restricted whole food plant-based diet and will learn behavioral weight loss strategies remotely, through an e-learning platform. | Behavioral: Whole Food Plant-Based Behavioral Weight Loss Treatment<br>* Over the course of 12-weeks, participants will be prescribed a non-energy-restricted whole food plant-based diet and will learn behavioral weight loss strategies through an e-learning platform. Each week, participants will also complete a 15-minute coaching call to provide positive reinforcement and problem-solving support.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Retention feasibility as assessed by the number of participants successfully retained in the intervention | The number of participants who are retained in the study, as defined by completing the post-treatment assessment and at least 10 out of 12 of the weekly intervention modules. Successful retention will be defined as at least 80% of participants being retained in the study. | Week 12 (post-intervention) | 
| Acceptability as assessed by self-reported acceptability of the intervention | Acceptability will be assessed with three items, in which participants will report the degree to which they were satisfied with the intervention, found the intervention to be helpful, and the likelihood that they would recommend it to family/friends on a Likert scale ranging from 1 (Not at all) to 5 (Very much). | Week 12 (post-intervention) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Preliminary effectiveness of the intervention on weight loss, as assessed by self-reported weight from baseline to post-intervention | Weight loss will be self-reported by participants weekly, and at baseline, mid-treatment, post-treatment, and 3-month follow-up. To evaluate the preliminary effectiveness of the intervention on weight loss, percent weight change from baseline to post-intervention will be evaluated. Preliminary weight loss effectiveness will be defined as at least 50% of participants losing at least 5% of their initial body weight by post-treatment. | Measured once weekly from Week 0 (baseline) to Week 12 (post-intervention), and at 3-month follow-up | 
| Preliminary effectiveness of the intervention on dietary intake, as assessed by self-reported dietary intake from baseline to post-intervention | Dietary intake will be assessed using a food frequency questionnaire tailored to examine adherence to the prescribed intervention (whole food plant-based) diet. A dietary adherence index ranging from 0 (no adherence) to 100 (complete adherence) will be created, and preliminary dietary change effectiveness will be defined as at least 80% of participants improved their dietary adherence score by at least 20% by post-treatment. | Week 0 (baseline), Week 6 (mid-treatment), Week 12 (post-intervention), and 3-month follow-up | 
| Preliminary effectiveness of the intervention on waist circumference, as assessed by self-reported waist circumference from baseline to post-intervention | Waist circumference will be self-reported by participants weekly, and at baseline, mid-treatment, post-treatment, and 3-month follow-up. To evaluate the preliminary effectiveness of the intervention on waist circumference, waist circumference change from baseline to post-intervention will be examined. Preliminary weight loss effectiveness will be defined as at least 50% of participants losing at least 5% of their initial waist circumference by post-treatment. | Week 0 (baseline), Week 6 (mid-treatment), Week 12 (post-intervention), and 3-month follow-up | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Weight loss, Behavioral weight loss, Overweight and obesity, Plant-based, Lifestyle modification