Log2Lose: Incenting weight loss and dietary self-monitoring in real-time to improve weight management

Abstract
In the past 40 years, the prevalence of obesity has increased at an alarming rate. Even modest weight loss of
at least 5% improves clinical parameters and quality of life. Efficacious behavioral weight loss programs teach
participants behavioral strategies to create and maintain a caloric deficit. The two strongest predictors of long-
term weight loss in such programs are initial weight loss and dietary self-monitoring. Over time, these
phenomena decline, limiting program effectiveness. Financial incentives to increase initial weight loss and self-
monitoring are appealing because they can be delivered to large populations with relative ease and at low cost.
Employers and payers have begun to provide financial incentives for health behaviors and outcomes despite
an inadequate evidence base to inform the optimal design of such interventions. The proposed study will
evaluate which incentive approach has the greatest impact and durability—incentivizing interim weight loss,
dietary self-monitoring, or both. Studies testing the effects of incentivizing these phenomena have showed
some promise for increasing short-term weight loss. Few studies have evaluated incentive effects on long-term
weight loss; examined the mediating role of intrinsic or extrinsic motivation; or calculated program costs or
cost-effectiveness of financial incentive interventions. In the proposed two-site, randomized, single-blinded,
longitudinal 2x2 factorial study, known as “Log2Lose,” we address these limitations by evaluating the individual
and joint effects of incentivizing, in near real-time, weekly weight loss and dietary self-monitoring on 6-month
weight loss and subsequent weight loss maintenance. People with obesity from the communities of Madison,
WI and Durham, NC will receive an 18-month intervention comprising: 1. An incentivized weight loss program
for 6 months (Phase I), 2. An incentivized weight maintenance program for 6 months (Phase II), and 3. A non-
incentivized weight maintenance program for 6 months (Phase III). Participants will be randomized to receive
adjunctive incentives for weekly weight loss, dietary self-monitoring, both, or neither. We will measure the
proportion of participants achieving clinically significant weight loss of ≥5% at 6 (primary endpoint), 12, and 18
months. We will assess whether extrinsic and intrinsic motivation mediate intervention effect; calculate
intervention costs; and calculate cost-effectiveness ratios across the four study arms. Our financial incentives
intervention was designed to be scalable by using available technology and automating the process of
analyzing data to provide incentives in near real-time. The intervention could be paired with various weight loss
interventions offered by clinicians or payers, or integrated into a variety of patient and consumer-facing
technologies. Completion of this study will contribute to our long-term goal of identifying and implementing
efficacious, cost-effective, scalable approaches to reduce the prevalence of obesity and associated health
outcomes.

Grant Number: 3UH3HL150558-05S1
NIH Institute/Center: NIH
Principal Investigator: Lisa CadmusBertram