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This protocol provides a methodological framework for conducting a meta-analysis to evaluate the effects of nutritional therapies on the nutritional status of gastric cancer patients. By following this protocol, researchers will be able to systematically identify, appraise, and synthesize evidence from randomized controlled trials and comparative studies. The steps include: formulating a comprehensive search strategy across multiple databases; dual-independent screening and selection of studies using predefined PICOS criteria (population, interference, comparison, outcome, and study design); standardized data extraction and harmonization of outcome measures; assessment of study quality using the Cochrane Risk of Bias 2.0 tool; and statistical synthesis using appropriate models, with exploration of heterogeneity and sensitivity analyses. Application of this protocol to the available evidence suggests potential benefits of specific nutritional interventions, e.g., oral supplementation for body weight, though high heterogeneity underscores the need for rigorous and standardized methodology in this field. A continuous model with fixed or random effects was used to get the mean difference (MD) with 95% confidence intervals (CIs). A total of 18 studies, involving 3,586 subjects, were selected for the meta-analysis. Oral nutritional supplementation had a significantly increased body weight (MD, 0.74; 95% CI, 0.20-1.27, p = 0.007) compared to the control in patients with gastric cancer. Early enteral nutrition had significantly improved prealbumin levels (MD, 22.53; 95% CI, 13.37-31.69, p < 0.001) compared to parenteral nutrition in patients. However, no significant differences were found between enteral immunonutrition and standard enteral nutrition for albumin (MD, 0.57, 95%CI, -0.31-1.44, p=0.20), prealbumin (MD, 0.23, 95%CI, -0.29-0.76, p=0.38), or transferrin levels (MD, 0.11, 95%CI, -0.09-0.32, p=0.28). The studied data showed that using oral nutritional supplementation had significantly increased body weight compared to control, and early enteral nutrition had significantly improved prealbumin levels compared to parenteral nutrition. However, more studies are required to validate this finding.