GoalTracker: Comparing Self-Monitoring Strategies for Weight Loss

This study is a randomized controlled trial that compares 3 self-monitoring approaches for weight loss. GoalTracker is a standalone, technology-based intervention using a commercial smartphone app (MyFitnessPal) and email.

The investigators hypothesize that the group that delays diet tracking and receives additional intervention components (weekly personalized feedback, skills training, and action plans) will have greater weight loss at the end of the 12-week intervention and at 6-month followup, compared to (a) an intervention group that simultaneously tracks weight and diet for all 12 weeks and receives the same additional components, and (b) a control group that tracks only diet.

This study will examine whether a digital health intervention (GoalTracker) can promote weight loss among adults who are overweight or obese. Engagement in self-monitoring often declines over time, which is then associated with suboptimal weight loss. Finding ways to improve self-monitoring engagement, particularly in the first month of treatment, is needed. Promoting mastery, self-efficacy, and self-regulatory skills may help with maintaining high engagement.

The investigators aim to enroll 105 participants. All groups are asked to self-monitor daily on their smartphone using the free commercial mobile application MyFitnessPal over the course of the 12-week intervention.

Specifically, the study aims to...

1. Determine the effect of a Sequential self-monitoring intervention, compared to a Simultaneous self-monitoring intervention on weight change, caloric intake change, and proportion of individuals achieving 5% weight loss.
2. Determine the effect of the Sequential self-monitoring intervention, compared to the Control, on the same variables.
3. Compare self-monitoring engagement by intervention arm.
4. Examine the relation between self-monitoring engagement and weight loss.
5. Investigate theoretical mediators (self-efficacy, mastery, and self-regulation) on the relation between treatment arm and weight change.

Eligibility Criteria:
Inclusion Criteria:

* ages 21-65 years old
* Body Mass Index (BMI) 25-45 kg/m2
* interested in losing weight through dietary change
* current use of iPhone or Android smartphone
* current use of email address
* has daily access to a bathroom scale
* no recent weight loss (≥10 lbs) in the past 6 months
* able to read and write in English
* able to attend 3 in-person evaluation visits at Duke University in Durham, North Carolina over a 3-month period

Exclusion Criteria:

* current participation in another weight loss treatment
* currently pregnant or planning to become pregnant within study period, or \< 1 year post-partum
* history of cardiovascular event, eating disorder, diabetes mellitus, hypothyroidism, cancer, end stage renal disease
* current uncontrolled hypertension
* use of the MyFitnessPal app to track food in the past 6 months
* Former or planned bariatric surgery
* current use of medication (e.g., lithium, steroids, anti-psychotics)
* use of weight loss medication in past 6 months
* profound cognitive, developmental, or psychiatric disorders or recent hospitalization in a psychiatric facility