Weight Loss
Conditions
Keywords
Weight Loss, Motivation, Contracts
Brief summary
This is a 4-arm, randomized controlled trial to evaluate the effectiveness of financial incentives to motivate and sustain long-term weight loss. The study will recruit eligible employees at a large health management company to participate in a 6-month weight loss program and have weight measurements for an additional 3-month follow-up period. The primary outcome measure in this randomized controlled trial will be pounds of weight lost. The experimental groups will include variations of deposit contracts (participants put their own money at risk, and lose that money if they fail to achieve their weight loss goal) and fixed payments. The use of deposit contracts is a powerful mechanism for inducing behavior change that is based on loss aversion, a psychological concept first described by Nobel Prize winner Daniel Kahneman and Amos Tversky in 1979. A deposit contract takes advantage of the fact that people typically feel the pain of a loss more than the pleasure of a gain, increasing ones motivation to reach a goal. The study hypotheses are 1) mean weight loss will be greater in all intervention groups compared to the control group by the end of 24 weeks; and 2) individuals in the intervention groups will have a lower mean weight at the end of the 3-month follow-up period than individuals in the control group.
Interventions
BEHAVIORALDeposit contract with a 1:1 match
Daily weigh-in for 24 weeks and if each daily goal met daily deposit amount is paid back with an additional matched amount equal to deposited amount. Final weigh-in at 36 weeks with no financial incentive or deposit made.
BEHAVIORALDeposit contract with a 2:1 match
Daily weigh-in for 24 weeks and if each daily goal met daily deposit amount is paid back with an additional matched amount twice the amount equal to deposited amount. Final weigh-in at 36 weeks with no financial incentive or deposit made.
BEHAVIORALDeposit Contract with no match
Daily weigh-in for 24 weeks and if each daily goal met the daily deposit amount is paid back. Final weigh-in at 36 weeks with no financial incentive or deposit made.
Sponsors
Carnegie Mellon University
Harvard University
incentaHEALTH
McKinsey & Company
University of Pennsylvania
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 70 Years
Healthy volunteers
No
Inclusion criteria
* Aged 18 to 70 (inclusive) * BMI between 30 and 50 (inclusive)
Exclusion criteria
* Inability to consent * No known Illiteracy and/or inability to speak, read, and write English * Participation in another weight loss program * Participation in another research study * Current treatment for drug or alcohol use * Consumption of 5 alcoholic drinks per day * Myocardial infarction or stroke within the past 6 months * Uncontrolled hypertension (defined as BP170 mm Hg systolic or BP110 mm Hg diastolic) * Current addiction to prescription medicines or street drugs * Serious psychiatric diagnoses (severe depression, schizophrenia) * Pregnancy * Diabetic and using any medicine besides metformin to control blood sugars * Metastatic cancer * Unstable medical conditions that would likely prevent the subject from completing the study * Previous diagnosis of an eating disorder * History of unsafe weight loss behaviors such as binging or the use of laxatives
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Weight | 24 Weeks | Change in weight between baseline and 24 weeks |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| 1 - Control | 33 |
| 2 - Deposit Contract With a 1:1 Match Deposit contract with a 1:1 match
Deposit contract with a 1:1 match: Daily weigh-in for 24 weeks and if each daily goal met daily deposit amount is paid back with an additional matched amount equal to deposited amount. Final weigh-in at 36 weeks with no financial incentive or deposit made. | 33 |
| 3 - Deposit Contract With a 2:1 Match Deposit contract with a 2:1 match
Deposit contract with a 2:1 match: Daily weigh-in for 24 weeks and if each daily goal met daily deposit amount is paid back with an additional matched amount twice the amount equal to deposited amount. Final weigh-in at 36 weeks with no financial incentive or deposit made. | 33 |
| Experimental 4 - Deposit With no Match Deposit contract with no match
Deposit Contract with no match: Daily weigh-in for 24 weeks and if each daily goal met the daily deposit amount is paid back. Final weigh-in at 36 weeks with no financial incentive or deposit made. | 33 |
| Total | 132 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 | FG002 | FG003 |
|---|---|---|---|---|---|
| Overall Study | Lost to Follow-up | 1 | 3 | 3 | 4 |
| Overall Study | Withdrawal by Subject | 1 | 1 | 0 | 0 |
Baseline characteristics
| Characteristic | 1 - Control | 2 - Deposit Contract With a 1:1 Match | 3 - Deposit Contract With a 2:1 Match | Experimental 4 - Deposit With no Match | Total |
|---|---|---|---|---|---|
| Age, Continuous | 45.9 years STANDARD_DEVIATION 9 | 44.3 years STANDARD_DEVIATION 11.5 | 42.0 years STANDARD_DEVIATION 9.6 | 43.5 years STANDARD_DEVIATION 9.6 | 43.9 years STANDARD_DEVIATION 10 |
| Sex: Female, Male Female | 27 Participants | 30 Participants | 26 Participants | 32 Participants | 115 Participants |
| Sex: Female, Male Male | 6 Participants | 3 Participants | 7 Participants | 1 Participants | 17 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk | EG003 affected / at risk |
|---|---|---|---|---|
| deaths Total, all-cause mortality | 0 / 33 | 0 / 33 | 0 / 33 | 0 / 33 |
| other Total, other adverse events | 0 / 33 | 0 / 33 | 0 / 33 | 0 / 33 |
| serious Total, serious adverse events | 0 / 33 | 0 / 33 | 0 / 33 | 0 / 33 |
Outcome results
Primary
Change in Weight
Change in weight between baseline and 24 weeks
Time frame: 24 Weeks
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| 1 - Control | Change in Weight | 1.0 pounds | Standard Deviation 7.6 |
| 2 - Deposit Contract With a 1:1 Match | Change in Weight | -5.3 pounds | Standard Deviation 10.1 |
| 3 - Deposit Contract With a 2:1 Match | Change in Weight | -2.3 pounds | Standard Deviation 9.8 |
| Experimental 4 - Deposit With no Match | Change in Weight | -4.3 pounds | Standard Deviation 8.9 |