Effectiveness of Roux-en-Y Gastric Bypass Versus Hypocaloric Diet in Reducing Cardiovascular Risk Factors in Obese Adults: A Systematic Review and Meta-Analysis

Background: Obesity-related dyslipidemia, hypertension, and insulin resistance are major global concerns. Roux-en-Y gastric bypass (RYGB) yields greater weight loss than lifestyle therapy, but its advantage over hypocaloric diets for cardiometabolic risk is uncertain. We compared RYGB with hypocaloric diets in adults with obesity. Methods: We included clinical trials and observational studies that enrolled adults (BMI ≥ 30 kg/m(2)) and compared RYGB with hypocaloric diets (500-1000 kcal/day deficit). The primary outcome was LDL-cholesterol; the secondary outcomes were HDL-cholesterol, BMI, systolic blood pressure, triglycerides, and HbA1c. Studies with additional procedures or co-interventions were excluded. PubMed, EMBASE, Scopus, Web of Science, and Google Scholar were searched through 1 July 2025. Risk of bias was assessed with RoB 2.0 and the Newcastle-Ottawa Scale. Random-effects meta-analyses were performed. Results: Eight studies (n = 622) met the criteria. Versus diet, RYGB did not significantly reduce LDL-cholesterol (MD -9.52 mg/dL; p = 0.09). Trends favored RYGB for BMI (MD -4.02 kg/m(2); p = 0.06) and triglycerides (MD -18.58 mg/dL; p = 0.06). Changes in HDL (+2.81 mg/dL), systolic blood pressure (-2.77 mmHg), and HbA1c (-0.22%) were small and non-significant. The certainty of evidence was low across outcomes. Conclusions: Current evidence does not demonstrate superiority of RYGB over hypocaloric diets for cardiometabolic risk markers. Dietary therapy remains first-line; RYGB may be considered for selected patients.