Fasting Halved Joint Tenderness in Rheumatoid Arthritis Patients: What the Research Shows

Medical disclaimer: This article summarises published research for informational purposes only. It is not medical advice and is not a substitute for guidance from a qualified health professional. Always consult your doctor before starting any fasting protocol, especially if you have an existing health condition or take medication.

Study at a Glance

What This Study Looked At

Researchers at Norway's National Hospital wanted to know whether prolonged fasting — followed by a long-term dietary change — could meaningfully reduce disease activity in patients with active rheumatoid arthritis (RA). RA is a chronic autoimmune condition in which the immune system attacks the joints, causing inflammation, pain, swelling, and eventual joint destruction. At the time, no dietary intervention had been rigorously tested in a randomised controlled trial against a control group. This study, published in The Lancet, was the first to do so. You can read more about fasting and inflammation in our article on how intermittent fasting reduces inflammation.

Who Was Studied

Participant profile: Adults with active RA as defined by the American Rheumatism Association criteria. Both groups stayed at the same Norwegian health farm (Vallersund Gard) for the initial period.

How the fasting protocol worked in this study: Participants fasted for 7–10 days on herbal teas, garlic, and vegetable broths — a very-low-calorie modified fast providing minimal energy. After the fast, they transitioned to a strict vegan diet for 3.5 months, then to a lacto-vegetarian diet for the remaining 9 months of the trial year. The control group stayed at the same health farm but continued eating ordinary food.

What the Researchers Found

Disease Activity (Primary Outcomes)

All objective measures of RA disease activity improved significantly in the fasting group at 4 weeks — while the control group showed no significant change.

Key findings:

• 26 of 27 patients in the fasting group reported feeling subjectively better at 4 weeks — compared with approximately 5 of 26 in the control group
• All primary objective outcome measures reached statistical significance in favour of the fasting group (p<0.01 for most measures)
• The Ritchie articular index (a standardised measure of joint tenderness) approximately halved in the fasting group over the first 4 weeks

Inflammatory Markers

ESR is a direct marker of systemic inflammation elevated in active RA. Its reduction in the fasting group confirmed that the subjective improvements were paralleled by objective biological changes.

What Did Not Change

• No significant adverse events were reported in the fasting group
• Weight loss occurred in the fasting group but was not the primary focus of the study
• Both groups were at the same health farm, controlling for stress, sleep, and environment variables

What the Researchers Concluded

The researchers concluded that fasting followed by a vegetarian diet produced significant, objective improvement in all measured outcomes in patients with active RA. Crucially, when patients maintained the vegetarian diet for one year, the improvements were sustained; those who returned to omnivorous eating lost the benefits.

What This Means If You Fast

• Anti-inflammatory fasting is real: This 1991 RCT provided early rigorous evidence that the relationship between fasting and inflammation reduction is clinically meaningful — not just theoretical. Modern meta-analyses on fasting and inflammation have since confirmed this across larger populations.
• The gut may be the mechanism: Dietary change after fasting — away from processed foods, red meat, and potential food antigens — is likely central to RA benefit. Fasting creates conditions for gut repair; the subsequent diet determines whether repair holds.
• Prolonged fasting (3+ days) appears to have stronger anti-inflammatory effects than short-term daily fasting in autoimmune conditions. The 7–10 day fast in this study allowed a deep metabolic and immune reset that a 16-hour daily window does not fully replicate.
• Duration matters: The benefits were only maintained when participants continued with a clean diet long-term. Fasting followed by a return to inflammatory dietary patterns did not preserve results. See our article on what to eat after breaking a fast for practical guidance.
• Not a cure, but a meaningful tool: RA is a serious autoimmune condition requiring medical management. Fasting should be considered a complementary approach — one with genuine evidence behind it — but never a replacement for appropriate medical treatment.
• Relevance to shorter IF protocols: While this study used prolonged fasting, everyday intermittent fasting still activates autophagy and reduces inflammation through the same underlying pathways, just to a lesser degree.

Study Limitations

• Small sample size (n=53 across both groups)
• The health farm setting makes it impossible to isolate fasting from other variables (rest, reduced stress, social support, environment)
• No placebo control is possible with a fasting intervention
• The vegetarian diet after fasting confounds whether fasting alone — without dietary change — would sustain benefits
• Study was conducted in 1991; RA diagnostic criteria and standard of care have evolved
• No long-term follow-up data beyond 1 year
• Conducted exclusively in a Norwegian population; generalisability to diverse ethnic groups is unknown
• No blinding possible due to the nature of the intervention

Source

Kjeldsen-Kragh J, Haugen M, Borchgrevink CF, Laerum E, Faegri M, Nesse T, Forre O, Oian S. (1991). Controlled trial of fasting and one-year vegetarian diet in rheumatoid arthritis. The Lancet, 338(8772), 899–902. PMID: 1681264

Frequently Asked Questions

Did fasting actually reduce joint pain in this study?

Yes. All objective measures of joint tenderness and disease activity improved significantly in the fasting group at 4 weeks, while the control group showed no significant change. 26 of 27 patients in the fasting group reported subjective improvement.

How long did participants fast in this study?

They fasted for 7–10 days on herbal teas, garlic, and vegetable broths. This is classified as prolonged fasting (3+ days), not standard daily intermittent fasting.

Did the benefits last after the fast ended?

Yes — but only for patients who maintained a vegetarian diet for the full year. Those who returned to omnivorous eating saw their RA activity worsen again, suggesting the dietary change post-fast was as important as the fast itself.

Is intermittent fasting safe for people with rheumatoid arthritis?

Standard daily intermittent fasting (16:8) is generally considered low-risk for most adults. Prolonged fasts of 7–10 days, as used in this study, require medical supervision — particularly for people on medications such as methotrexate, biologics, or corticosteroids. Always consult your rheumatologist before starting any fasting protocol.

What makes fasting anti-inflammatory?

Fasting lowers insulin, reduces blood glucose, activates autophagy (cellular clean-up), and alters gut microbiome composition. Together, these effects reduce the production of pro-inflammatory cytokines such as TNF-α, IL-6, and CRP — the same markers elevated in rheumatoid arthritis. See how intermittent fasting reduces inflammation for a deeper look.

Related Research and Articles

• How intermittent fasting reduces inflammation
• Intermittent fasting and inflammation: the research explained
• What is autophagy and when does it start during fasting?
• Fasting and digestive disorders: the case for giving your gut a rest
• Does intermittent fasting help with chronic pain?
• Intermittent fasting and autoimmune conditions in women
• Can intermittent fasting improve gut health?

Want the complete guide to fasting? Get Intermittent Fasting in Practice on Amazon — and claim 3 months free on our fasting app at fastinginpractice.com/redeem.