Purpose: This study examined the effect of frequent nutritional counseling on oral intake, body weight, response rate, survival, and quality of life in patients with cancer of the lung (small-cell), ovary, or breast undergoing cyclic chemotherapy. Patients and Methods: Of 105 assessable patients, 57 were randomized to receive nutritional counseling, and 48 to receive no nutritional counseling and consumption of an ad lib oral intake. The intervention group was counseled to achieve a daily energy and protein intake according to recommended dietary allowances. Counseling was standardized and performed by a trained dietitian, and took place twice monthly during a 5-month period from start of chemotherapy. Results: Dietary counseling increased daily energy intake by approximately 1 MJ and protein intake by 10 g over the entire study period. There was no change in the control group. Counseling led to an insignificant increase in body weight, but triceps skinfold measurement increased significantly after 5 months. Response rate and overall survival did not differ between the groups. Quality of life measured by the Quality-of-Life index (QL-index) increased significantly in both groups, but did not differ between groups. Conclusion: No clinical benefit could be demonstrated despite long-term and continuous improved food intake in cancer patients with solid tumors undergoing aggressive chemotherapy.