Understanding the Impact of Meal Timing on Neurological Health in Adults With Multiple Sclerosis

The goal of this clinical trial is to learn if the time an individual eats each day impacts neurological health in people with multiple sclerosis. The main questions the investigators are asking are: 1. Does meal timing affect biomarkers of neuronal health (neurofilament light chain \[NfL\] and BDNF) and inflammation (IL-6, IL-17, TNF-ɑ) in adults with MS. 2. Does meal timing affect expression of circadian clock genes and genes associated with autophagy in adults with MS. Participants will be instructed to start and stop eating at specific times each day based on their group assignment and their personal schedule. They will respond to prompts sent to them on their smartphone to record the times they start and stop eating each day. As a secondary goal, the study will also explore the feasibility of including translocator protein (TSPO)-PET imaging of neuroinflammation in future clinical trials of TRE in people with MS. To accomplish this, imaging will be completed in a subset of 8 participants at the beginning and end of the study.

Inclusion Criteria: * Diagnosed with relapsing remitting or secondary progressive multiple sclerosis (RRMS or SPMS) * If on disease modifying therapy (DMTs), stable for 6 months * If not on DMTs, no DMT usage within previous 6 months * BMI 18.5-50 kg/m2 * Access to a smartphone * Responsible for personal eating schedule or able to have input into schedule Exclusion Criteria: * Relapse within previous 30 days * Actively engaged in a weight loss program or unwilling to follow assigned eating schedule * Current use of GLP-1 or use within previous 3 months * Regularly fasts \> 12 hours/day * Employed in night shift or rotating shift work * Unable to walk 25 feet with or without assistive device (EDSS \> 6.5). * Current use of insulin or sulfonylurea agents * Pregnant or breastfeeding * Currently enrolled in another trial that would confound results (e.g., exercise studies or other diet studies)