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Overweight and ObesityNudgeNCT03836391

Precision Public Health: Enhancing Connections to Develop Just-in-Time Adaptive Intervention Strategies

A study testing Nudge in people with Overweight and Obesity and Overweight, run by University of North Carolina, Chapel Hill at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

The purpose of this pilot study is to examine the effects of different types of just-in-time intervention messages on daily meeting dietary, activity, and weighing goals in a sample of young adults participating in a mobile-based weight loss program. Read more about this study

Who is it for?
Ages 18 to 35 yearsHealthy volunteers can take part
Conditions the study is for
Overweight and Obesity, Overweight, Obesity
What is being tested?
Nudge
Could I receive a placebo?
No, everyone receives an active treatment
How many people
53 participants
Where
1 siteUnited States
Study dates
12 Feb 2019to 16 Sep 2019
Phase
Interventional
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 35 years
  • All sexes
  • Healthy volunteers accepted
  • Adult

Who may be able to join

  • Age 18-35
  • BMI of 25-40 kg/m²
  • Not adhering to the US physical activity guidelines of at least 150 moderate-to-vigorous intensity activity minutes/week
  • English-speaking and writing
  • No pre-existing medical condition(s) that preclude adherence to an unsupervised exercise program, diabetes treated with insulin, history of heart attack or stroke, current treatment for cancer, or inability to walk for exercise
  • Has an iPhone with iOS 11 (or willing to download it) with internet access and text messaging plan
  • Has home wireless access compatible with Fitbit Aria 2 scale (802.11b/g/n)

Who cannot join

  • Current participation in another physical activity or weight control program
  • Currently pregnant, pregnant in last 6 months, or planning pregnancy in next 3 months
  • Report a heart condition, chest pain during periods of activity or rest, loss of consciousness, joint or bone problems, or prescription medicine usage for blood pressure or heart condition on the Physical Activity Readiness Questionnaire (PAR-Q)
  • Health or psychological diagnoses that preclude participation in a prescribed dietary and exercise program, including diagnosis of schizophrenia or bipolar disorder, hospitalization for a psychiatric diagnosis in the past year, diagnosis of alcohol or substance abuse
  • Occupation requires primarily night shift work
  • Owns and uses a physical activity tracker
Show all 9Show fewer
  • Moving out of area in next 4 months
  • Out of town for a week or more during study period
  • Not willing to attend two study visits

Trial locations and contacts

1 site in 1 country.

United States1 site

  • Department of Health Behavior, University of North Carolina, Chapel Hill

    Chapel Hill, North Carolina, 27599

Other trials in United States

About this study

The purpose of this pilot study is to examine the effects of different types of just-in-time intervention messages on daily meeting dietary, activity, and weighing goals in a sample of young adults participating in a mobile-based weight loss program.

Read the detailed description

Public health interventions typically rely on a set schedule of intervention delivery. Advances in technology and computer tailoring allow us to go from a "one size fits all" approach to one that uses digital health data to deliver "just-in-time adaptive interventions," or JITAIs, that can vary the timing, dose, and content of intervention messages to individuals. This pilot study is a micro-randomized trial that evaluates the effects of various intervention message options delivered in JIT moments on meeting dietary, activity, and weighing goals among young adults in a mobile-based weight loss program.

The Nudge study is a 12-week mobile health weight loss program delivered via a native smartphone application. Individuals are asked to track their red foods (high-calorie, high-fat foods) in the app daily and meet their personalized red foods goal, wear a Fitbit daily and meet their daily active minutes goal, and weigh daily on their WiFi-enabled scale. Up to 4 times each day, participants are randomized to receive or not receive intervention messages in order to examine the effects of these intervention message types on meeting daily weighing goals, red food goals, and activity goals. This is a within-subjects design in which each participant serves as their own control, and data is analyzed at the person-day level.

Being tested
Nudge
Keywords
Mobile health, Physical activity, Nutrition, Self-monitoring, Smartphone app, Digital health tools
Medical subject headings
Overweight, Obesity, Motor Activity

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • NudgeBehavioural

    Nudge is a smartphone-app-based micro-randomized trial that tests the effect of 7 intervention message types based on behavior change techniques on daily goal attainment. Participants have three daily goals: weigh daily, red foods goal, and active minutes goal.

Study groups in NCT03836391
Study groupRoleWhat they receive
Nudge InterventionExperimentalEach of 7 intervention message options has specific decision rules (including weighed/not weighed and progress toward daily dietary and activity goals) that make a participant eligible to receive a specific intervention type at a specific time (decision points). At each decision point (early morning, morning, midday, and evening), the system evaluates which intervention options a participant is eligible to receive, and randomly chooses one intervention option from that list. Then the participant is randomly assigned to either receive or not receive that intervention message (with a 50-50 probability).
Receives: Behavioral: Nudge

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Percent of person-days with same-day weighing

    Percent who weighed after the message randomization time until the end of the day (at the participant-day level) across the 12-week study

    Measured: from Baseline to Week 12

  2. Percent of person-days with next-day weighing

    Percent who weighed the day after the message randomization (at the participant-day level) across the 12-week study

    Measured: from Baseline to Week 12

  3. Percent of person-days met active minutes goal on same day

    Percent who met active minutes goal after the message randomization time until the end of the day (at the participant-day level) across the 12-week study

    Measured: from Baseline to Week 12

  4. Percent of person-days met active minutes goal on next day

    Percent who met active minutes goal the day after the message randomization (at the participant-day level) across the 12-week study

    Measured: from Baseline to Week 12

  5. Percent of person-days met red foods goal on same day

    Percent who met red foods goal after the message randomization time until the end of the day (at the participant-day level) across the 12-week study

    Measured: from Baseline to Week 12

  6. Percent of person-days met red foods goal on next day

    Percent who met red foods goal the day after the message randomization (at the participant-day level) across the 12-week study

    Measured: from Baseline to Week 12

Secondary outcomes (3)

  1. Number of active minutes

    Total number of active minutes on the day of message randomization (at the participant-day level) across the 12-week study

    Measured: from Baseline to Week 12

  2. Proximal effect of message on total red foods today

    Total number of red foods on the day of message randomization (at the participant-day level) across the 12-week study

    Measured: from Baseline to Week 12

  3. Mean weight change

    Mean weight change across participants

    Measured: from Baseline to Week 12

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted11 Feb 2019
  2. Study start12 Feb 2019
  3. Primary completion16 Sep 2019
  4. Study completion16 Sep 2019

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Model description
Each participant-time point is randomized between intervention message or no intervention message
Masking
None (open label)
Enrolment
53 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT03836391
Sponsor's protocol ID
16-0775
Acronym
Nudge
Status last verified
Nov 2019
First submitted
7 Feb 2019
Last updated
13 Nov 2019
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Publications

  • Valle CG, Nezami BT, O'Shea NG, Hatley KE, Tate DF. Outcomes of a pilot microrandomized trial of just-in-time adaptive intervention messages nudging weight-related behaviors in young adults. Digit Health. 2025 Jul 6;11:20552076251353267. doi: 10.1177/20552076251353267. eCollection 2025 Jan-Dec.

    PubMed 40631347

Questions about this trial

What is this clinical trial studying?

A study testing Nudge in people with Overweight and Obesity and Overweight, run by University of North Carolina, Chapel Hill at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 7 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 13 Nov 2019. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Percent of person-days with same-day weighing (time frame: from Baseline to Week 12). The study lists 6 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT03836391, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 13 Nov 2019.

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