To learn if exercise and weight management can help to improve feelings of fatigue in CLL survivors.

Primary Objective:

--Evaluate the impact of an organized, longitudinal, diet and exercise training program on fatigue as assessed by the Functional Assessment of Cancer Therapy (FACT) score in patients with CLL.

Secondary Objectives:

--Assess changes in physical activity, dietary behavior, physical function using the PROMIS physical function questionnaire and performance tests of physical function, body mass index (BMI) and global quality of life. Additionally, we will assess changes in fecal microbiome composition, metabolic parameters including a comprehensive lipid panel, glucose, insulin, TNF alpha, IL6, leptin, resistin, adiponectin, IGF1 and IGFBP1 and immunologic function as assessed by T cell and monocyte phenotypic and functional assays in patients with CLL after participation in the behavioral intervention.

Exploratory Objectives:

-- Identify differences in the metabolic, immunologic and fecal microbiome composition in patients with CLL who have a high CLL comorbidity index score (CLL-CI) compared to patients with CLL and a low CLL-CI score. And, investigate the association of comorbidity score, disease features, CLL-specific prognostic factors and clinical outcomes.

Inclusion Criteria:

• Adults age 18-85 years of age with a histologically confirmed diagnosis of CLL and the ability to provide signed informed consent.
• Self-reported physical activity will be assessed prior to enrollment and patients with a physical activity level below the level prescribed in our study will be eligible for inclusion.

Exclusion Criteria:

• Other active malignancy within 1 year of study enrollment (excluding non-melanoma skin cancer)
• Richter's transformation, another medical condition which would prevent safe participation in the behavioral intervention
• Major surgery within 1 month of enrollment
• Non-English speakers
• Cognitively impaired adults
• Pregnancy.