Objective: The closed-loop gastric electrical stimulation (CLGES) abiliti ® system provides tailored gastric electrical stimulation activated by food entry into the stomach and sensor-based data to medical professionals. The aim of this study was to analyze behavior changes using sensor-based food intake and activity data in participants treated with the CLGES system., Methods: Food intake and activity data (3D accelerometer) were downloaded at baseline and monthly/bimonthly for 12 months in a subset of patients with obesity (N = 45) participating in a multicenter trial with CLGES. Measured food intake parameters included the number of intakes during allowed and disallowed periods, nighttime intakes, and between-meal snacks (average/d). Activity parameters included time in different levels of physical activity (min/d), sleep/sedentary (h/d), and estimated energy expenditure (EE)., Results: Weight loss at 12 months averaged 15.7 ± 7.7% of the baseline body weight. Stable reduction in the number of disallowed meals and between-meal snacks (P < 0.05), an increase in all levels of physical activity (P < 0.001), and an increase in activity-based EE (303 ± 53 kcal/d on average, P < 0.001) were seen., Conclusions: Significant improvement in eating and activity was seen in participants. It is hypothesized that feedback of the sensor-based data induced behavioral changes and contributed to weight loss in patients treated with CLGES., (© 2017 The Obesity Society.)