Fasting and Rheumatism: What 277 Historical Cases Showed

Rheumatism — the old-fashioned term for painful, inflamed joints and connective tissue — was one of the most common conditions that Upton Sinclair documented in his 1911 book The Fasting Cure. His survey of 277 fasting episodes found rheumatism among the conditions most frequently reported as improved or resolved. Over a century later, modern inflammation research is beginning to explain why.

The Historical Record

In The Fasting Cure, Sinclair gathered first-hand reports from 109 readers who had tried therapeutic fasting, collectively describing 277 fasting episodes. Of the conditions reported, rheumatism appeared repeatedly — multiple cases described significant relief from joint pain, swelling, and stiffness after fasts ranging from a few days to several weeks.

Sinclair's explanation was straightforward for 1911: he believed that overfeeding created fermentation in the digestive tract, producing toxins that accumulated in the joints and connective tissues. Fasting, in his view, gave the body a chance to clear these accumulated poisons. The tongue test was central to his thinking — during a fast, the tongue becomes heavily coated as toxins are expelled, then gradually clears as the body purifies itself.

One case described a man with severe rheumatism whose legs were described as painfully swollen. After a seven-day fast followed by a careful light diet, he returned to farm work — chopping wood and pitching hay — within weeks.

To be clear: these are anecdotal reports from 1911, not clinical trials. Sinclair himself acknowledged they could not be considered scientific proof. But the sheer volume of consistent reports pointing in the same direction is worth examining, especially in light of what we now know about fasting and inflammation.

Citation: Sinclair, U. (1911). The Fasting Cure. Mitchell Kennerley.

What Modern Science Adds

Sinclair's "toxins and fermentation" theory was the language of his era. Modern science describes the same phenomenon in different terms — and the underlying mechanism is real.

Inflammatory markers. Research now shows that fasting significantly reduces circulating inflammatory markers including C-reactive protein (CRP), TNF-alpha, and interleukin-6 (IL-6). These are the same proteins elevated in rheumatoid arthritis and other inflammatory joint conditions. By reducing their levels, fasting reduces the biological fuel that drives joint inflammation.

Insulin and joint inflammation. High insulin — a direct result of frequent eating, especially sugar and refined carbohydrates — promotes a state of systemic low-grade inflammation. Joints are particularly susceptible. When insulin drops during fasting, this inflammatory background noise decreases. Many people notice joint pain improves markedly within 2–4 weeks of consistent fasting.

Uric acid and gout. Elevated uric acid is one of the classic causes of joint pain, particularly gout. While fasting can temporarily raise uric acid in the very short term, longer-term intermittent fasting is associated with lower uric acid levels. The reduction in dietary purines and improved kidney clearance during extended eating restriction contribute to this effect.

Autophagy and cellular cleanup. Sinclair's idea that the body "burns disease tissue first" during a fast turns out to have a modern parallel. Autophagy — the cellular recycling process activated by fasting — breaks down dysfunctional proteins and cell debris. Research suggests autophagy plays a role in clearing the misfolded proteins involved in some forms of arthritis.

What the Cases Suggest About Duration

In Sinclair's survey, most people who reported rheumatism benefit fasted for 5–12 days. Modern intermittent fasting protocols are far shorter, but the principle still applies: consistent, repeated fasting windows accumulate anti-inflammatory benefits over weeks and months.

For someone with joint pain today, the relevant question is not "should I fast for 10 days?" but rather "what happens when I fast 16–18 hours consistently for 6–12 weeks?"

The short answer: inflammatory markers fall, insulin levels stabilize, and many people with joint pain report measurable relief.

Practical Tips for People with Rheumatism or Joint Pain

Start with food quality first. Sinclair's most consistent observation across all his cases was that dietary change and fasting worked together — not fasting alone. Remove sugar, grains, seed oils, and ultra-processed foods from the eating window. Add healthy fats (olive oil, butter, avocado), quality proteins, and fermented vegetables.

Give it time. Joint inflammation does not resolve overnight. Most people who see genuine improvement report noticing it between weeks 3 and 8 of consistent fasting. The anti-inflammatory effect accumulates.

Hydration matters. Sinclair emphasized drinking large amounts of water throughout any fast. Modern advice is the same — dehydration concentrates inflammatory compounds and can make joint pain worse.

Consider electrolytes. Sodium, potassium, and magnesium all drop during fasting and their deficiency can contribute to muscle cramps and joint discomfort. Sea salt in water, magnesium supplements, and potassium-rich foods like avocado help maintain balance.

For the Complete Fasting Guide

For a full practical system on fasting — including how to manage food, hunger, and common side effects — get Intermittent Fasting in Practice on Amazon. Buy the book and claim 3 months free on our fasting app at https://www.fastinginpractice.com/redeem

Frequently Asked Questions

Can fasting cure rheumatoid arthritis?

No controlled clinical evidence supports fasting as a cure for rheumatoid arthritis. What research does show is that fasting reduces inflammatory markers associated with the condition, and many people report reduced pain and stiffness. Anyone with a diagnosed autoimmune condition like RA should work with a rheumatologist before making major dietary changes.

How long does it take for fasting to reduce joint pain?

Most people who experience improvement from fasting report it within 3–8 weeks of consistent practice. This aligns with the time it takes for systemic inflammatory markers to meaningfully fall with a sustained fasting protocol.

Did Upton Sinclair personally have rheumatism?

Sinclair's own main complaint was chronic headaches and nervous exhaustion, not rheumatism. But he documented multiple rheumatism cases from readers. His own results were primarily about mental clarity and resolution of his headaches and chronic fatigue.

What kind of fasting helps most with inflammation?

Consistent daily intermittent fasting — 16 to 18 hours — appears to produce meaningful reductions in CRP and other inflammatory markers. The key is consistency over weeks, not a single long fast.

Is it safe to fast if I take medication for arthritis?

Fasting can affect how some medications are absorbed and metabolized. If you take NSAIDs, methotrexate, steroids, or biologics, speak with your doctor before starting a fasting protocol. Some medications require food to reduce stomach irritation.

Related Articles

• Does intermittent fasting reduce inflammation?
• Intermittent fasting and inflammation: the research explained
• Can intermittent fasting help with chronic pain?

This article draws on historical research from 1911 and is for informational purposes only — not medical advice. Always consult a qualified healthcare professional before making any dietary changes.