Carbohydrate-Restricted Diet in Treating Patients with Previously Treated Prostate Cancer

Inclusion Criteria

• Received prior radical prostatectomy (with or without post-operative radiation) or definitive local radiation for prostate cancer (either external beam radiation, brachytherapy, or combination)
• PSA within the past 2 months is between 3 and 20 ng/ml if patient received local radiation OR between 0.4 and 20 ng/ml if patient received prior radical prostatectomy
• PSADT > 3 months and < 36 months * Calculated based at least 2 values that are post-treatment and > 0.2 in the prior 2 years with the first and last PSA separated by at least 3 months * Use all values in the last 2 years that are post-treatment and > 0.2 to calculate PSADT * PSADT calculated while NOT on androgen deprivation therapy (ADT) * If prior ADT use, then documented either A) normal testosterone or B) a testosterone within 50 points of normal and stable (defined as a second testosterone at least 6 weeks later that is equal or lower than the first testosterone) is required before starting to calculate PSADT
• Body mass index (BMI) >= 24 kg/m^2
• Willing to be randomized to a no dietary intervention control group or to a low-carbohydrate diet group
• Reads, writes, and understands English

Exclusion Criteria

• Anticipate needing secondary prostate cancer therapy within the next 6 months (i.e. radiation, or hormonal therapy)
• Current use of weight loss medications including herbal weight loss supplements or enrolled in a diet/weight loss program
• Currently on therapy aimed at lowering testosterone levels (includes gonadotropin-releasing hormone [GnRH] agonist/antagonist, prior bilateral orchiectomy, oral anti-androgens, or 5-alpha reductase inhibitors); testosterone replacement is allowed but treatment should be stable during the entire study
• Known distant metastatic disease
• Already consuming a carbohydrate-restricted or vegetarian diet
• Unable or unwilling to adhere to a carbohydrate-restricted dietary intervention
• Weight loss > 5% of body weight in the last 6 months based on self-report
• Medical comorbidities that in the opinion of the investigator limits the patient’s ability to complete this study