Outcome
| Type |
Measure |
Description |
Time frame |
Safety issue |
| Other |
Preliminary effectiveness of the intervention on quality of life, as assessed by self-reported quality of life from baseline to post-intervention |
Quality of life will be assessed using the 36-item Short-Form General Health Survey (SF-36). The SF-36 assesses eight domains: physical functioning, limits due to physical health, pain, general health, energy/fatigue, social functioning, emotional wellbeing, and mental health. Scores in each domain are converted to a scale from 0 to 100, with higher scores indicating better functioning in each domain. This scale produces both physical and mental health component summaries, both of which will be examined. A reliable change index at the .20 level will be calculated for both the physical- and mental- health-related component scores. If the product exceeds a z-score of 1.282 at post-treatment, reflecting 80% confidence, then results will be defined as suggestive of preliminary quality of life effectiveness. |
Week 0 (baseline), Week 6 (mid-treatment), Week 12 (post-intervention), and 3-month follow-up |
|
| Other |
Association between plant-based diet history at Week 0 (baseline) and percent weight loss at Week 12 (post-treatment) |
To assess plant-based diet history, a plant-based diet familiarity score will be computed from participants' self-reported familiarity with plant-based diets, reported on a scale ranging from 0 (Not at all familiar) to 4 (Very familiar), and from reports of whether they have eaten a plant-based diet in the past, for at least 3-months. Participants will be given 4 points if previously vegan, 3 if previously vegetarian, 2 if previously pescatarian or 1 if previously semi-vegetarian ("flexitarian"). These scores will be added to self-reported plant-based diet familiarity, resulting in a "plant-based diet familiarity" score that could range from 0 to 7. To evaluate the potential moderating effect of plant-based diet history on weight loss outcomes, the correlation between plant-based diet history and post-treatment percent weight loss will be examined. |
Week 0 (baseline) and Week 12 (post-treatment) |
|
| Other |
Association between social support vs. social sabotage at Week 6 (mid-treatment) and percent weight loss at Week 12 (post-treatment) |
To assess social support vs. social sabotage, participants will complete the Social Support and Sabotage Scale from Ball & Crawford (2006). On this measure, participants separately rate the degree to which friends and family act in ways that support or hinder their healthy eating efforts with a Likert scale ranging from 1 (Almost never) to 5 (Almost always). Scores will be averaged for each subscale to compute: 1) support for health behaviors from friends, 2) support for health behaviors from family, 3) sabotage for health behaviors from friends, and 4) sabotage for health behaviors from family. To evaluate the potential moderating effect of social support vs. social sabotage on weight loss outcomes, the correlations between social support vs. social sabotage for health behavior scores and post-treatment percent weight loss will be examined. |
Week 6 (mid-treatment) and Week 12 (post-treatment) |
|
| Other |
Association between internal disinhibition at Week 0 (baseline) and percent weight loss at Week 12 (post-treatment) |
To assess internal disinhibition, participants will complete the disinhibition subscale from the Mindful Eating Questionnaire (MEQ; Framson et al., 2009). Responses are on a Likert scale ranging from 1 (Never/Rarely) to 4 (Usually/Always). Scores for each item are averaged to compute an overall disinhibition score. To evaluate the potential moderating effect of internal disinhibition on weight loss outcomes, the correlation between internal disinhibition and post-treatment percent weight loss will be examined. |
Week 0 (baseline) and Week 12 (post-treatment) |
|
| Other |
Association between self-compassion at Week 0 (baseline) and percent weight loss at Week 12 (post-treatment) |
To assess self-compassion, participants will complete the Self-Compassion Scale-Short Form, which assess how participants generally treat themselves during difficult times. Responses are on a Likert scale ranging from 1 (Almost never) to 5 (Almost always). Scores for each item are averaged to compute an overall self-compassion score. To evaluate the potential moderating effect of self-compassion on weight loss outcomes, the correlation between self-compassion and post-treatment percent weight loss will be examined. |
Week 0 (baseline) and Week 12 (post-treatment) |
|
| Other |
Association between psychological flexibility at Week 6 (mid-treatment) and percent weight loss at Week 12 (post-treatment) |
To assess psychological flexibility, participants will complete the personalized psychological flexibility index, which assesses the ability to pursue valued life aims despite the presence of distress. Responses are on a Likert scale ranging from 1 (Strongly Disagree) to 7 (Strongly Agree). Scores for each item are averaged to compute an overall psychological flexibility score. To evaluate the potential moderating effect of psychological flexibility on weight loss outcomes, the correlation between psychological flexibility and post-treatment percent weight loss will be examined. |
Week 6 (mid-treatment) and Week 12 (post-treatment) |
|
| Primary |
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) |
|
| Primary |
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 |
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 |
|
| Secondary |
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 |
|
| Secondary |
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 |
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