The aim of the present trial is to evaluate the effect of lifestyle changes on the natural history of indolent lymphomas, during the period of watchful waiting. The intervention program is comprised of specifically designed vegan nutrition, physical activity, mostly aerobic, and stress reduction by relaxation and meditation. Outcome results will be followed and analyzed for 3 years, taking into consideration the following parameters - disease burden, specific disease-related symptoms, relevant blood tests, body weight, indicators of well-being. Changes in these parameters will be correlated with the level of compliance and adherence to the intervention program. The results of the trial group of patients will be further compared to the natural history of the disease in a comparable group of patients during their waiting period who were not subject to the above intervention.

Inclusion Criteria:

• Age ≥ 18 years old
• Patient sex - male and female
• Diagnosis with indolent lymphoma in low-grade lymphoma (follicular lymphoma (FL), marginal zone lymphoma MZL), as assessed by Groupe d'Etude des Lymphomes Folliculaires (GELF) criteria
• Lack of need and non treatable patients at the time of diagnosis
• Existence of detailed medical information about physical activity and dietary habits
• Patients who have signed an informed consent form to participate in the study.

Exclusion Criteria:

• Need for therapeutic intervention
• Administration of chemotherapy and / or monoclonal antibodies or immunomodulatory preparation
• Chronic inflammatory or infectious disease
• Another malignant disease
• Pregnant women, special populations - children and incapacitated of judgment