Early weight loss in a standalone mHealth intervention predicting treatment success

OBJECTIVE: Early weight loss is a strong predictor of longer‐term and clinically meaningful weight loss but has not been studied in the context of mobile health (‘mHealth’) interventions. METHODS: GoalTracker was a randomized trial among adults (21–65 years) with overweight or obesity comparing three 12‐week standalone mHealth interventions for weight loss. All arms received a free commercial mobile app (MyFitnessPal) for daily self‐monitoring of diet and/or weight and a goal to lose 5% of weight by 3 months. Collapsing across arms, this analysis examined participants with a 1‐month weight (n = 84), categorizing them as either early responders (≥2% weight loss at 1 month) or early non‐responders (<2% weight loss at 1 month). RESULTS: Early responders – 36% of participants – had greater per cent weight change at 3 months (−5.93% [95% confidence interval: −6.82%, −5.03%]) than early non‐responders (−1.45% [−2.15%, −0.75%]), which was sustained at 6 months (−5.91% [−7.33%, −4.48%] vs. −1.28% [−2.37%, −0.19%]; ps < 0.0001). Over half (57%) of early responders achieved ≥5% weight loss at 3 months vs. 11% of early non‐responders. At 4 weeks, self‐monitoring frequency (weight/diet) was significantly greater among early responders, which continued across 12 weeks. CONCLUSION: Responding early to an mHealth treatment is associated with higher engagement and greater likelihood of achieving clinically meaningful weight loss.