Evaluation of a Letter Intervention Promoting a Plant-based Diet
Public ClinicalTrials.gov record NCT03880838. Field values are reproduced from the official study page; the official ClinicalTrials.gov record remains the source of truth for eligibility, enrollment, and contact information.
Data is sourced from official ClinicalTrials.gov public API records. Always review the official ClinicalTrials.gov record for the latest information.
Official title
Evaluation of a Letter Intervention Among At-risk Adults Promoting a Plant-based Diet Using a Combination of Provider Testimonials, the Forks Over Knives Documentary, and Commitment- or Prevention-focused Behavioral Nudges
Brief summary
Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.
The researchers' mission is to promote healthier eating behavior and to reduce costs associated with healthcare. The purpose of this study is to evaluate the effects of mailing randomly selected participants a letter promoting a plant-based diet. Depending on the experimental condition, participants may additionally receive a free documentary, Forks Over Knives, and they may also get letters which use commitment- or prevention-focused messages to encourage watching the documentary and changing their eating behavior. The researchers hypothesize that receiving the documentary will be associated with lower insurance claims and improved health outcomes one and two years later. The researchers also hypothesize that using either commitment- or prevention-focused messages will also contribute to lower insurance claims and improved health outcomes compared to experimental conditions where materials did not include these messages. This study will help the researchers design evidence-supported programs that can improve people's health.
Study identification
- NCT ID
- NCT03880838
- Recruitment status
- Completed
- Study type
- Interventional
- Phase
- Not applicable
- Enrollment
- 11,234 participants
Conditions and interventions
Conditions
Interventions
- Personal testimonial Behavioral
- Forks Over Knives Documentary Behavioral
- Commitment nudge Behavioral
- Prevention nudge Behavioral
Behavioral
Eligibility (public fields only)
- Age range
- 18 Years and older
- Sex
- All
- Healthy volunteers
- Healthy volunteers not accepted
This page does not interpret eligibility. Detailed inclusion and exclusion criteria are on the official ClinicalTrials.gov record.
Study timeline
- Start date
- Jun 19, 2019
- Primary completion
- Jun 29, 2020
- Completion
- Jun 29, 2022
- Last update posted
- May 19, 2025
2019 – 2022
United States locations
- U.S. sites
- 1
- U.S. states
- 1
- U.S. cities
- 1
| Facility | City | State | ZIP | Site status |
|---|---|---|---|---|
| Geisinger Health System | Danville | Pennsylvania | 17822 | — |
Site contact phone numbers, emails, and investigator names are intentionally not displayed here. Open the official ClinicalTrials.gov record for site contact information.
About this trial record page
- What this page shows
- Public field values for ClinicalTrials.gov record NCT03880838, including study identification, conditions, interventions, eligibility (age, sex, healthy volunteer), timeline, and U.S. site list.
- What this page does not do
- No medical advice, eligibility judgments, treatment recommendations, study quality scoring, or AI-generated medical summaries. No site contact phone numbers, emails, or investigator names.
- Where the data comes from
- Sourced from the official ClinicalTrials.gov public API. The official record is the source of truth.
- Last refresh
- Last update posted May 19, 2025 · Synced Sep 2, 2026
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Open the official record
The complete protocol, eligibility criteria, and contact information for NCT03880838 live on ClinicalTrials.gov.