Comparative effectiveness of guided weight loss and physical activity monitoring for weight loss and metabolic risks: A pilot study

•A personal activity monitor was as effective as health coaching for weight loss.•Combination of health coaching and monitor led to larger reductions in risk.•Self-monitoring devices may provide cost-effective potential for weight loss.

Many consumer-based physical activity monitors (PAMs) are available but it is not clear how to use them to most effectively promote weight loss. The purpose of this pilot study was to compare the effectiveness of a personal PAM, a guided weight loss program (GWL), and the combination of these approaches on weight loss and metabolic risk. Participants completed the study in two cohorts: Fall 2010 and Spring 2011. A sample of 72 obese individuals in the Ames, IA area were randomized to one of 3 conditions: 1) (GWL, N = 31), 2) PAM, N = 29, or 3) a combination group (PAM + GWL, N = 29). Weight and metabolic syndrome score (MetS), computed from waist circumference (WC), BMI, blood pressure (BP), and lipids were assessed at baseline and following an 8-week intervention. Weight was also assessed four months later. Two-way (Group × Time) ANOVAs examined intervention effects and maintenance. Effect sizes were used to compare magnitude of improvements among groups. During the intervention, all groups demonstrated significant improvements in weight and MetS (mean weight loss = 4.16 kg, p < 0.001). Mean weight continued to decline modestly during follow-up, with average weight loss of 4.82 kg from baseline (p < 0.01). There were no group differences for weight loss but the PAM + GWL group had significantly larger changes in MetS score (d = 0.06-0.77). The use of PAM resulted in significant improvements in weight and MetS that were maintained across a four-month follow-up. Evidence suggests that the addition of GWL contributed to enhanced metabolic outcomes.