Endpoint: The effect of the diet on tumor proliferation rate will be measured by making comparisons of 1) percentage of positive cells containing the marker Ki-67, 2) PSA-levels, 3) CCP-score in the two groups. Tumor tissue from prostate biopsies taken during surgery (the end of the study) and the most recent biopsy taken before the beginning of the study will be collected. Blood samples will be taken at the beginning of the study, at the day before the surgery, and 3 months after surgery, and send to analysis of PSA (free and total). The absolute differences in PSA levels and the PSA doubling time will be calculated. In addition the investigators will measure the expression of AR, ERα and ERß in tumor tissue and the blood levels of hormones, testosterone, DHT, estradiol and 3ß-Adiol.