PURPOSE: Randomized clinical trials (RCT) are inconclusive regarding the role of dietary interventions in anthropometric measurements and survival in breast cancer patients. Our aim was to conduct a systematic review and meta-analysis to assess the effects of diet on these outcomes in women treated for early-stage breast cancer. METHODS: Embase, MEDLINE, the Cochrane Database of Systematic Reviews, and the Cochrane Central Register of Controlled Trials were searched for RCT comparing dietary interventions (individualized dietary counseling, prescription of a specific diet, or others) with usual care in women that were treated for early breast cancer. Primary outcomes were overall survival (OS) and disease-free survival (DFS); secondary outcome was a change in body mass index (BMI). RESULTS: We found 12 RCT eligible for analysis, 7 of which were included in the quantitative analysis. Two studies reported OS and DFS and 6 reported BMI data. The hazard ratio (HR) for OS and DFS was 0.91 (95% confidence interval [CI] 0.77-1.07, p = 0.25) and 0.92 (95% CI 0.79-1.08, p = 0.31) for the intervention and control groups, respectively. Intervention was associated with BMI reduction in subjects who received a specific diet instead of counseling or other types of intervention (-0.67; 95% CI -1.14 to -0.21). CONCLUSIONS: Despite increasing survival among breast cancer patients due to better oncological treatments, there is still a lack of prospective data regarding the effects of dietary interventions in this population. We found positive association between prescription of specific diets in terms of anthropometric measures; there were no differences in OS or DFS.