Inclusion Criteria:

          -  Understand and voluntarily sign consent form

          -  Able to adhere to study protocol

          -  Demonstrated use of internet and email

          -  Access to internet at least 4 days per week

          -  Willingness to change diet, physical activity and weight

          -  Willingness to be randomized to immediate start or standard of care

          -  Histologically confirmed diagnosis of adenocarcinoma of the prostate with evidence of
             biochemical recurrence following local therapy (surgery and radiation will be
             allowed). Biochemical recurrence will be defined as a PSA > 1 ng/mL on at least two
             occasions, separated by at least 1 month.

          -  Surgically treated men must not be eligible for or decline salvage radiation. Men who
             recurred within 3 years of completion of salvage radiation will be included.

          -  Definitive therapy (surgery or radiation) should be at least 4 weeks from time of
             consent.

          -  Men who received prior hormone therapy with definitive local therapy (standard with
             radiation) are permitted if serum testosterone level is >150 ng/dL and hormone
             treatment was discontinued > 1 year from time of enrollment.

          -  Body mass index >= 25 kg/m2

          -  Eastern Cooperative Oncology Group (ECOG) performance status < 2

          -  Willingness to return for clinical visit at 6 months, 12 months, and 24 months

        Exclusion Criteria:

          -  Any evidence of nodal or metastatic disease.

          -  Any clinical or radiographic evidence of metastatic disease by computed tomography
             (CT) of the chest, abdomen and pelvis and technetium-99 bone scintigraphy (bone scan)

          -  Time to biochemical recurrence >3 years after definitive local therapy

          -  PSA doubling time >12 months

          -  MI, stroke or ASCVD procedure within 6 months

          -  Serious medical condition likely to hinder accurate measurement of weight, or for
             which weight loss is contraindicated, or which would cause weight loss

          -  Unstable angina or medical conditional that would prevent routine exercise

          -  Prior or planned bariatric surgery

          -  Use of prescription weight loss medication (including off label use of medications) or
             over-the-counter orlistat within 6 months

          -  Use of testosterone replacement therapy within 6 months

          -  Chronic use (at least past 6 months) of medications likely to cause weight gain or
             prevent weight loss (e.g. corticosteroids, lithium, olanzapine, risperidone,
             clozapine), including androgen deprivation therapy

          -  Unintentional or intentional weight loss within 6 months of enrollment (≥ 5% of body
             weight)