PATIENT CHARACTERISTICS: Age: 48 to 78 Sex: Female Menopausal status: Postmenopausal Performance status: Not specified Life expectancy: At least 10 years (excluding breast cancer) Hematopoietic: WBC at least 3,000/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 1.5 mg/dL AST no greater than 60 IU/mL (or within 2 times normal) Renal: Creatinine no greater than 1.5 mg/dL Cardiovascular: No active cardiac disease that would preclude doxorubicin in patients assigned to adjuvant chemotherapy with doxorubicin Other: Baseline caloric intake at least 20% fat Accessible for follow-up and by telephone Sufficient memory required to provide food recall data Must speak and read English Medically and nutritionally eligible for either dietary intervention arm No prior or concomitant malignancy except curatively treated nonmelanoma skin cancer or carcinoma in situ of the cervix