The Dietary Intervention to Enhance Tracking with mobile (DIET Mobile) study: A six-month randomized weight loss trial

OBJECTIVE: To examine the use of two different mobile diet self-monitoring methods for weight loss. METHODS: Overweight adults (n=81; mean BMI 34.7±5.6 kg/m(2)) were randomized to self-monitor their diet with a mobile app (App, n=42) or wearable Bite Counter device (Bite, n=39). Both groups received the same behavioral weight loss information via twice weekly podcasts. Weight, physical activity (International Physical Activity Questionnaire), and energy intake (2 dietary recalls) were assessed at 0, 3, and 6 months. RESULTS: At six months, 75% of participants completed the trial. The App group lost significantly more weight (-6.8±0.8 kg) than the Bite group (-3.0±0.8 kg; group×time interaction: P<0.001). Changes in energy intake (-621±157 App, -456±167 Bite; P=0.47) or number of days diet was tracked (90.7±59.2 App, 68.4±61.2 Bite; P=0.09) did not differ between groups, but the Bite group had significant increases in physical activity METs min/wk (+2015.4±684.6; P=0.02) compared to little change in the App group (-136.5±630.6; P=0.02). Total weight loss was significantly correlated with number of podcasts downloaded (r=-0.33, P<0.01) and number of days diet was tracked (r=-0.33, P<0.01). CONCLUSIONS: While frequency of diet tracking was similar between the App and Bite groups, there was greater weight loss observed in the App group.