The purpose of this study is to determine what effects (good or bad) a whole-food plant-based diet and nutritional coaching has on overweight or obese patients who are being treated with androgen deprivation therapy (ADT) for their prostate cancer. This study will assess whether participants lose weight and how their cholesterol levels change with the diet.

This research study is being done because we know from prior studies that prostate cancer patients on ADT are at a higher risk for weight gain, diabetes, high cholesterol, and other associated health problems; overweight men have a higher risk of their prostate cancer progressing; and overweight patients may have more inflammation which can also contribute to cancer progression. Plant-based and other diets are generally associated with weight loss and a lower risk for diabetes and heart disease. We aim to determine if a whole-food plant-based diet may be more effective in helping overweight or obese patients on ADT lose weight and decrease their risk of diabetes, heart disease, and other health problems, and possibly diminish the risk of prostate cancer progressing.

Participants will be randomized into one of two treatment groups. Randomization is like flipping a coin and there is a 50/50 chance of being assigned to either group. The first group will follow a whole-food plant-based diet and the second will follow a standard diet targeted to improve diet quality and weight management. Both groups will receive nutritional counseling.   

The whole-food plant-based diet group will receive home-delivered meals for 28 days with 12 meals a week followed by 28 days with 6 meals a week. The next 18 weeks, participants will eat self-prepared WFPBD meals. This group will receive nutrition coaching throughout the entire study.

The second group will receive general nutritional counseling weekly for the first 2 months (8 scheduled calls), followed by monthly calls for 4 months. 

Total study participation for both groups will last 26 weeks and includes documenting what you eat and how you feel during the study, collecting and analyzing blood tests and stool samples, and obtaining a special scan to determine the percentage of fat in your body.