Purpose To determine whether Hispanic residents receiving the Healthy Fit intervention enhanced with Motivational Interviewing (MI) experienced greater improvements in body composition, relative to participants receiving the initial intervention. Design Quasi-experimental evaluation. Setting El Paso, Texas. Sample Among 656 baseline participants, 374 (54%) completed the 12-month assessment. Intervention In Healthy Fit, community health workers (CHWs) promote nutrition and exercise. To strengthen intrinsic motivation and help participants overcome barriers to change, we incorporated a 30-minute motivational interview into the baseline assessment. Follow-up phone calls at 1, 3, and 6 months were identical across conditions. Measures CHWs assessed body mass index (BMI) and body fat percentage (BFP) using a bioelectrical impedance scale. Analysis Regression models estimated differences between intervention conditions on change in BMI and BFP from baseline to the 12-month assessment. Results Participants receiving MI had 2.13 times higher odds of losing weight (OR = 2.14, 95% CI [1.30, 3.53], P = .003) and 2.59 times higher odds of reduced BFP (OR = 2.59, 95% CI [1.51, 4.41], P < .001), relative to initial intervention participants. MI participants lost an average of 1.23 kg (2.71 lbs.) and their BFP declined 2% over 12 months. Conclusion Findings suggest CHW use of MI is a promising approach for promoting incremental changes in diet and exercise, which Healthy Fit integrates into a low-cost intervention.