This study was designed to provide scientific evidence on the effectiveness of worksite-based dietary intervention to reduce obesity among overweight/obese employees.Electronic search was performed using Ovid Medline, Embase, Cochrane Library, and CINAHL databases. The keywords used were "obesity," "nutrition therapy," and "worksite." The internal validity of the randomized controlled trials (RCTs) was assessed using the Cochrane's Risk of Bias. Meta-analysis of selected studies was performed using Review Manager 5.3.A total of seven RCTs with 2,854 participants were identified. The effectiveness of dietary interventions was analyzed in terms of changes in weight, body mass index (BMI), total cholesterol, and blood pressure. The results showed that weight decreased with weighted mean difference (WMD) of -4.37 (95% confidence interval (CI): -6.54 to -2.20), but the effectiveness was statistically significant only in short-term programs < 6 months ( = 0.001). BMI also decreased with WMD of -1.26 (95% CI: -1.98 to -0.55), but the effectiveness was statistically significant only in short-term programs < 6 months ( = 0.001). Total cholesterol decreased with WMD of -5.57 (95% CI: -9.07 to -2.07) mg/dL, demonstrating significant effectiveness ( = 0.002). Both systolic (WMD: -4.90 mmHg) and diastolic (WMD: -2.88 mmHg) blood pressure decreased, demonstrating effectiveness, but with no statistical significance.The worksite-based dietary interventions for overweight/obese employees showed modest short-term effects. These interventions can be considered successful because weight loss was below approximately 5-10 kg of the initial body weight, which is the threshold for the management of obesity recommended by the Scottish Intercollegiate Guideline Network (SIGN).