Understanding Mechanisms of Health Behavior Change

Status

Completed

Phases

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT03192254

Enrollment

Registered

2017-06-20

Start date

2017-07-13

Completion date

2018-03-30

Last updated

2023-08-01

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Diet Modification, Incentives, Overweight and Obesity

Brief summary

This research seeks to examine psychological factors that may impact relationship between incentives and health behavior engagement, specifically fruit and vegetable consumption. Additionally, it will compare the impact of two different incentive schedules on behavior engagement, one providing immediate rewards (i.e. rewards received on a daily basis) and another providing delayed rewards (i.e. rewards received at the end of the study period), with a control condition in which no rewards are offered. Study participants will provide reports of their fruit and vegetable consumption each day for three weeks, and in the two incentive conditions, they will receive small monetary rewards for their fruit and vegetable consumption. Following the three week reporting and reward period, participants will complete two additional assessments, measuring psychological constructs and behavior engagement following the cessation of rewards. The study will also examine how cognitive and anthropomorphic factors may contribute to intervention response and the effects on psychological constructs.

Interventions

BEHAVIORALself-monitoring

recording fruit and vegetable consumption

BEHAVIORALdaily monetary incentives

daily payments for consuming fruits and vegetables

BEHAVIORALdelayed lump sum monetary incentives

lump sum payments for consuming fruits and vegetables

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

BASIC_SCIENCE

Masking

SINGLE (Subject)

Eligibility

Sex/Gender

ALL

Age

18 Years to No maximum

Healthy volunteers

Yes

Inclusion criteria

* Consume fewer than 3 servings/day of fruits and vegetables * Daily access to internet for 3 weeks following baseline session * Have or are willing to create an account on PayPal * BMI greater than or equal to 25, from self-reported height and weight

Exclusion criteria

Design outcomes

Primary

Measure	Time frame
Fruit and vegetable consumption, servings per week	3 Weeks
Perceived behavioral control scale score	3 Weeks
Attitude scale score	3 Weeks

Secondary

Measure	Time frame
Intrinsic motivation scale score	3 Weeks

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026