Dietary treatment of overweight/ obese men with prostate cancer has not been well studied. As men with prostate cancer who are overweight/ obese are at an increase risk of recurrence, metastasis and mortality, elucidating a diet that will both improve biomarkers for prostate cancer and lead to long-term weight management could improve survivorship. The primary objective of this proposal is to compare a plant-based, olive oil (PBOO) diet to a conventional diet for weight loss and improvement in metabolic biomarkers (specifically fasting insulin, glucose, and triglycerides) for overweight/ obese men diagnosed with prostate cancer on surveillance or who have had an asymptomatic biochemical failure after primary therapy. The secondary objective is to determine which diet will be more acceptable for long term use. Participants will consume for 8 weeks each a conventional diet for treating prostate cancer and a PBOO diet for weight loss and improvement in biomarkers with random assignment to the diet order. They will choose one of the diets for 6 months of follow-up. Blood samples and body weight will be obtained pre- and post diet and after 6 months of follow-up and compared between the diets. Based on earlier work by colleagues of the PI, it is anticipated that the PBOO diet will result in better weight loss and biomarkers and will be more acceptable for long-term weight management. This protocol has the potential to elucidate a diet that will improve the body weight and survival of men with prostate cancer.
