The impact of fasting and caloric restriction on rheumatoid arthritis in humans: A narrative review.

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease affecting approximately 1 % of the global population. It is characterized by swollen and painful joints eventually evolving into bone erosion, cartilage degradation and systemic inflammation, that significantly reduce patients' quality of life. While modern pharmacological treatments often lead to symptom improvement, they are also accompanied by substantial side effects, which can further impair patient wellbeing. Dietary interventions, particularly fasting and caloric restriction (CR), have gained increasing attention as adjunctive strategies for RA prevention and treatment. Their anti-inflammatory potential and ability to modulate the gut microbiome render them an attractive option to accompany or modify medical treatment. However, high-quality research on fasting and CR interventions in humans with RA remains limited, and the underlying mechanisms are not yet fully understood. The present narrative review reflects our current knowledge regarding fasting and CR, emphasising their impact on clinical outcomes, potential underlying mechanism and the sustainability of their effects. Evidence suggests that fasting and CR may lead to short-term improvements in RA disease activity, including reductions in inflammatory markers such as C-reactive protein (CRP) and interleukin-6 (IL-6). However, their long-term efficacy remains uncertain due to the limited duration of most studies. Future research should focus on identifying optimal fasting and CR protocols and their feasibility in long-term disease management, along with investigating patient adherence and potential risks associated with fasting interventions.