Results have been mixed as to whether dietary counseling improves clinical outcomes in cancer patients. This systematic review and meta-analysis of randomized trials assessed the effect of dietary counseling on quality of life (QOL). It included only randomized trials that focused on dietary counseling and that relied upon a standardized QOL measurement. Five trials that met these and all other a priori eligibility criteria were identified; they are the focus of this meta-analysis. When these five studies were examined in aggregate, the standardized mean difference in QOL scores among patients who received dietary counseling was 0.56 (95% confidence interval,-0.01-1.14; P = 0.06). Dietary counseling does not appear to improve QOL significantly in patients with cancer. However,an observed trend toward benefit underscores the need for further study.