Effect of a Fasting Mimicking Diet on Patients With Multiple Sclerosis (FMDMS)

Inclusion Criteria: * Diagnosis of MS (AJ Thompson et al 2018) * Able to give informed consent * Able to tolerate MRI * Age 18 to 55 years * Disease duration 6 months to 20 years (included) * EDSS 0 to 6 * No change in immunomodulatory therapy in the 6 months prior to enrollment (not on immunomodulatory therapy is acceptable) * No glucocorticoid use within 30 days prior to screening * No serologic evidence of vitamin B12 deficiency or hypothyroidism * No Vitamin D deficiency (\< 30 ng/ml) Exclusion Criteria: * Relapse \< 60 days. * Any active or chronic infection (e.g. HIV, Syphilis, untreated TB) * Previous history of a malignancy other than basal cell carcinoma of the skin or carcinoma in situ that has been in remission for more than one year * Severely limited life expectancy by another co-morbid illness * History of previous diagnosis of myelodysplasia or previous hematologic disease or current clinically relevant abnormalities of white blood cell counts * Pregnancy or risk of pregnancy (this includes patients who are unwilling to practice active contraception during the duration of the study) * eGFR \< 60 mL/min/1.73m2 or known renal failure or inability to undergo MRI examination * Inability to give written informed consent in accordance with research ethics board guidelines * Known alimentary allergy or intolerance to any of the ingredients of the FMD regimen or the presence of diabetes * Underweight