Low-Fat, High-Fiber Diet Compared to a Standard Diet in Treating Patients With Prostate Cancer

OBJECTIVES: * Compare the inhibition of growth of human prostate cancer cell lines by serum from patients with prostate cancer before and after being fed a low fat, high fiber diet. * Determine the underlying mechanism through which a low fat, high fiber diet affects the growth of prostate cancer cell lines. * Determine whether a low fat, high fiber diet inhibits the growth of prostate cancer cell lines through androgen-dependent and/or androgen- independent mechanisms in these patients. * Determine the growth factors, hormones, and/or binding proteins that may be responsible for affecting the growth of prostate cancer cell lines in these patients. OUTLINE: This is a randomized study. Patients are randomized to 1 of 2 arms. * Arm I: Patients receive a low fat, high fiber diet daily for 3 weeks. * Arm II: Patients receive a control diet containing the standard amounts of fat and fiber. PROJECTED ACCRUAL: A total of 40 patients (20 per arm) will be accrued for this study within 6 months.