Carbohydrate Restriction and Prostate Cancer Growth

Inclusion Criteria:

- Received prior radical prostatectomy or definitive local radiation for prostate cancer
(either external beam radiation, brachytherapy, or combination)

- PSA within the past 3 months is between 0.4 and 20 if prior radical prostatectomy, or
between 3 and 20 ng/ml if prior radiation therapy.

- PSA doubling time (PSADT) >3 months and <36 months

1. Calculated based at least 2 values (at least 0.2) in the prior 2 years with the
first and last PSA separated by at least 3 months

2. Use all values in the last 2 years to calculate PSADT

3. PSADT calculated while NOT on androgen deprivation therapy (ADT).

4. 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.

- BMI >=24 kg/m2

- Willing to be randomized to a no-diet control or a low-carbohydrate diet

- 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

- Medical comorbidities that in the opinion of the investigator limits the patient's
ability to complete this study