Thirteen studies that included 1414 cancer patients were identified for analysis, although the quality varied and the clinical and statistical heterogeneity was substantial. Nutritional intervention resulted in statistically significant improvements in weight and energy intake, although no difference was observed after removing the studies responsible for heterogeneity. However, some aspects of the quality of life including emotional functioning, dyspnea, loss of appetite, and global quality of life were improved. Nutritional intervention had no effect on mortality