A Study of a Plant-Based Diet in People With Monoclonal Gammopathy of Undetermined Significance (MGUS) or Smoldering Multiple Myeloma (SMM)

Inclusion Criteria: * BMI ≥25 * Confirmed diagnosis of MGUS or SMM * M spike (immunoglobulin) ≥0.2 g/dL or abnormal free light chain ratio with increased level of the appropriate involved light chain * Secretory disease * Age ≥18 years * Willingness to comply with all study-related procedures * ECOG performance status of 0-3 * Interest to learn to cook plant based recipes Exclusion Criteria: * Patients that already follow a whole foods plant based or vegan diet (ovo-lactovegetarian diets are not excluded) * Legume allergy * Severe allergies, such as anaphylactic shock to peanuts * Concurrent participation in weight loss/dietary/exercise programs * Mental impairment leading to inability to cooperate * Enrollment onto any other therapeutic investigational study * Concurrent pregnancy * Patients with a known diagnosis of diabetes mellitus will not be excluded but will need to be followed regularly with an endocrinologist/primary care physician during the trial period. * Positive HBV, HCV, HIV PCR testing * Non English speaking * ≥ Grade 2 electrolyte abnormalities as defined by CTCAEv5.0 (need to be resolved before enrolling on study) * If in the opinion of the investigator there maybe any concerns regarding the ability of the patient to complete the study safely