This is a 6-week ketogenic diet (KD) intervention where participants with rheumatoid arthritis (RA) will follow a KD plan, supervised and monitored by a dietician. Participants will be provided extensive educational and ongoing support on the KD, including personalized coaching with the ability to text a dietitian at any time and expect a response within 12 hours. Diet adherence and progress will be assessed daily using at-home blood ketone/glucose monitors, along with diet records. Participants will fill out health related questionnaires and undergo assessments of body composition, RA disease activity. This study also includes blood draws and fat biopsy of the abdominal region.

Inclusion Criteria:

• Diagnosis of RA according to the ACR/EULAR 2010 criteria for RA.
• On stable doses of DMARDs and/ or biological agents (≥ 2 months prior to study enrollment)

Exclusion Criteria:

• Chronic inflammatory/ autoimmune disease other than RA (e.g. gout, inflammatory bowel disease such as Crohn's disease or ulcerative colitis, lupus, myositis, etc.)
• Prednisone or other glucocorticoid use in the last 4 weeks (exception: intra-articular glucocorticoid injections)
• Insulin use
• Hospitalization in the 30 days prior to study enrollment
• Acute or uncontrolled disease (e.g. cirrhosis, COPD, CKD)
• Malignancy
• Chronic infection (HIV, hep B/C, etc.)
• Heavy drinking
• On a ketogenic diet or exogenous ketone supplement (lses than 3 months prior to study enrollment)
• Recent weight loss (>5% in the last 2 months)