A Randomized Incentive-Based Weight Loss Trial in Singapore

• Percent body fat [ Time Frame: Baseline, 4 months, 8 months, 12 months ] [ Designated as safety issue: No ]
• Self-reported physical activity [ Time Frame: Baseline, 4 months, 8 months, 12 months ] [ Designated as safety issue: No ]
• Steps, aerobic steps and minutes of physical activity [ Time Frame: Monthly through month 8 (in incentive arms) ] [ Designated as safety issue: No ]
• Intrinsic and Extrinsic motivation [ Time Frame: Baseline ] [ Designated as safety issue: No ]
• Sociodemographics [ Time Frame: Baseline ] [ Designated as safety issue: No ]
• Health-related quality of life [ Time Frame: Baseline, 4 months, 8 months, 12 months ] [ Designated as safety issue: No ]
• Intervention costs [ Time Frame: Baseline through month 8 ] [ Designated as safety issue: No ]

The purpose of this study is to test the extent to which incentives, when combined with an existing evidence-based weight loss program, improve weight loss and weight loss maintenance. It will also compare the cost-effectiveness of the incentive-based weight loss programs to the basic program without incentives.

Globally, the rise in obesity rates has reached epidemic proportions, and in Singapore 53% of adults have a body mass index (BMI) great than 23.0 kg/m2, a level that increases risk for chronic disease among Asians. This study aims to test the extent to which traditional or behavioural economic incentives, when combined with an existing evidence-based weight loss program, improve weight loss and weight loss maintenance. Data will be collected through a two-arm (basic weight loss program, basic program plus traditional or behavioural economic incentives) randomized controlled trial (RCT) where key outcome variables are defined as weight loss (kilograms) at 8 months when the incentive program concludes, and at 12 months, after a 4 month period in which no additional incentives are provided. We hypothesize that at both 8 and 12 months, weight loss will be greater in the incentive arm than in the arm without incentives. The growing obesity epidemic, the high costs of obesity to employers, insurers and governments across Asia, and the fact that the incentive program is designed to be close to cost neutral, suggest that this research has high potential to have a significant public health impact, both in Singapore and the region.

Individuals aged 21 and above with a BMI greater than 25.

• Obesity
• Incentives

• Control
  Control participants will attend a 4-month structured weight-loss program and attend subsequent follow-ups at 4-month intervals upon completion of the program.
• Incentives
  Incentive arm participants will be offered an additional program (in addition to the COMM program) where they can earn incentives for meeting specified weight loss targets or step goals. They will be offered a choice between traditional (payments with certainty) and behavioral(payments paid via lottery) incentives.
  Intervention: Other: Financial Incentives

Inclusion Criteria:

• Signed informed consent
• Age 21+
• BMI 25+
• Willing to be randomized into 1 of the 2 study arms
• Willing to pay the $399 entry fee
• Stated willingness to commit to participating in all assessments regardless of weight change or study arm

Exclusion Criteria:

• Current pregnancy/lactation (women who become pregnant during the study will be withdrawn)
• Type 1 diabetes
• Type 2 diabetes on medication other than Metformin
• End-stage Renal Disease
• Ischemic Heart Disease requiring intervention in the past 6 months
• Thyroid disease that has yet to stabilize
• Changes in weight of greater than 3% in the past 6 months
• Use of weight loss medication in the past 6 months
• Malignancy requiring chemotherapy/radiation in the past 5 years
• Acute medical problems requiring 3+ days of missed work during previous 4 week period
• Any serious hospitalization or surgery in the past 6 months
• Use of corticosteroids in the past 6 months
• Answer 'YES' to any of the PAR-Q questions
• Unable to obtain MD consent from a physician giving permission to participate in the study
• Evidence of clinical depression (as assessed by the Beck Depression Inventory)
• Currently on medications for a mental health or substance abuse condition
• Evidence of binge eating based on the Binge Eating Disorders Scale (BEDS)
• Unable to communicate in English
• Additional concerns in which the clinical investigator deems problematic for participation