Fasting and Appendicitis: What Sinclair's Cases Reveal

In Upton Sinclair's 1911 book The Fasting Cure, he documented 277 cases of people who fasted for various health conditions. Among them were three cases of appendicitis. These accounts are striking because, at the time, the only medical option for appendicitis was surgery — and not everyone survived it. That three people reportedly found relief through fasting alone was, to Sinclair, further evidence that the body could heal itself when given the chance to rest.

This article looks at what Sinclair recorded, what it might mean, and how modern medical thinking has evolved on fasting and digestive health.

Historical Context: Appendicitis in 1911

Appendicitis — inflammation of the appendix — was a feared diagnosis in the early twentieth century. Surgical techniques were improving, but mortality from appendix removal operations was still significant. Many patients who could not afford surgery or who distrusted the operating theatre looked for alternatives.

Sinclair himself was deeply sceptical of conventional medicine, having spent what he estimated at $15,000 on physicians, sanatoriums, and druggists over eight years with little lasting benefit. His framework, drawn from Upton Sinclair (1911), The Fasting Cure (Mitchell Kennerley), was that most digestive illnesses arose from overfeeding and the fermentation of excess food in the gut. Rest the digestive system completely — fast — and the body would do what it could not do while constantly digesting.

What the Three Cases Showed

Sinclair did not provide extensive clinical detail for the appendicitis cases in his survey. What he reported was consistent with his broader pattern: people who fasted for several days described the acute symptoms settling down. He noted that half of the cases in his entire survey where cures did not hold were attributed to incorrect eating after the fast ended — not to the fast itself failing.

For appendicitis specifically, Sinclair's theory was that the inflammation was driven by toxic fermentation in the intestine — the same root cause he identified behind rheumatism, chronic headaches, and dozens of other conditions. By stopping all food intake, the gut was completely rested, fermentation ceased, and the inflamed tissue had the opportunity to calm down before it progressed to rupture.

This was not a surgical cure. It was, in Sinclair's framing, an interruption of the disease process at an early stage.

What Modern Medicine Says

It is critical to be direct here: appendicitis is a medical emergency. A ruptured appendix can be fatal within hours. If you experience severe pain in the lower right abdomen, fever, nausea, and loss of appetite — the classic appendicitis signs — the correct action is to seek emergency care immediately. Do not fast and wait.

That said, modern medicine has produced some genuinely interesting findings that echo parts of Sinclair's thinking, though not in a way that validates fasting as a treatment for appendicitis.

Uncomplicated appendicitis and antibiotics. Several recent studies, including large European trials, have found that uncomplicated appendicitis (no perforation, no peritonitis) can sometimes be treated with antibiotics rather than immediate surgery. Around 70–80% of carefully selected patients have avoided surgery in these trials, though recurrence rates mean the comparison with surgery is still being studied. The principle — that acute appendiceal inflammation can sometimes settle without cutting — has some contemporary backing.

Gut rest and inflammation. There is solid evidence that periods of gut rest reduce intestinal inflammation more broadly. In conditions like Crohn's disease and ulcerative colitis, elemental diets (liquid nutrition that requires no digestion) and even short fasts have been used to calm acute flares. The underlying principle — that reducing the digestive workload lowers inflammatory stress in the gut — has real biochemical support.

Fasting and the microbiome. More recent research has shown that intermittent fasting improves gut microbiome diversity, reduces intestinal permeability, and lowers systemic inflammation markers. None of this directly addresses appendicitis, but the broader picture of fasting as a tool for gut health has grown substantially since Sinclair's time.

What Sinclair Got Right (and Where He Was Limited)

Sinclair was a journalist, not a physician. He collected cases, noticed patterns, and drew conclusions that often outpaced his evidence. The three appendicitis cases in his survey represent what appears to have been acute appendicitis that did not progress to rupture — whether because of the fast or because the body resolved it naturally is impossible to know from historical accounts.

What he did identify, long before modern gut research confirmed it, was the concept that the digestive system needs rest to heal. The gut wall, the microbiome, and the immune tissue that lines the intestine all benefit from periods when food is not passing through. Sinclair called this "digestive rest." Modern researchers call it mucosal repair and barrier function restoration.

He was also right that breaking a fast incorrectly — eating a heavy meal too quickly — could cause serious harm. One of his cases involved a person who broke a 50-day fast improperly and caused intestinal abrasions. That specific caution about refeeding is now well-supported by the medical concept of refeeding syndrome.

Connection to Modern Fasting Practice

For people doing regular intermittent fasting — a 16:8 window, for example — none of this suggests fasting as a response to appendicitis symptoms. What it does reinforce is the well-supported idea that a daily fasting window gives the gut time to rest and repair. The mucosal lining of the intestine requires periods without food to maintain its integrity. Eating continuously, around the clock, denies the gut this essential recovery time.

Sinclair was observing something real, even if his causal theory (fermentation as the root of all disease) was oversimplified. The gut is not just a passive tube — it is an active immune organ that benefits from cycles of work and rest. That is a principle intermittent fasting practitioners today experience in practice.

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Frequently Asked Questions

Can fasting cure appendicitis?

No. Appendicitis is a medical emergency requiring immediate professional evaluation. A ruptured appendix can be life-threatening. Do not attempt to fast through appendicitis symptoms. Seek emergency medical care.

What did Sinclair report about appendicitis and fasting in 1911?

Sinclair documented three cases in his 277-person survey where people with appendicitis reported improvement through fasting. He framed this as the body redirecting healing energy once digestion stopped. These are historical anecdotes, not clinical evidence.

Is there any modern evidence that fasting helps gut inflammation?

Yes — fasting has been shown to improve gut microbiome diversity, reduce intestinal permeability, and lower inflammatory markers in the gut. These effects are well-documented for conditions like metabolic syndrome and IBD, though not specifically for appendicitis.

What is the connection between gut health and intermittent fasting?

Regular fasting windows allow the gut lining to repair, the microbiome to diversify, and intestinal immune tissue to function optimally. These are documented benefits of time-restricted eating that align with Sinclair's original observations about the value of digestive rest.

Should I mention Sinclair's cases to my doctor?

You are welcome to — but in a historical, informational context. Your doctor will correctly note that the cases lack clinical documentation, and that modern standards of care for appendicitis involve immediate evaluation. Intermittent fasting can be discussed as a general wellness tool, but not as a treatment for acute conditions.

Related Articles

• Why your digestive system needs a complete rest
• Fasting and digestive disorders: the case for giving your gut a rest
• How to break a fast safely: a step-by-step guide

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.

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