Upton Sinclair's $15,000 Medical Bill and How Fasting Changed Everything

In 1911, one of America's most famous writers published a short book that had nothing to do with meatpacking scandals or social injustice. It was about not eating. And it began with a confession that still resonates more than a century later: he had spent a small fortune trying to get well, and it had not worked.

Upton Sinclair's The Fasting Cure is best understood as a story about what happens when a desperate, curious person stops trusting the system and starts trusting their body. What he discovered — and what he shared with hundreds of readers who wrote back to him — forms one of the most compelling historical records of fasting as a health practice.

Historical Context: The Medical Landscape of 1911

At the turn of the twentieth century, medicine was undergoing rapid professionalisation. Physicians, surgeons, and sanatoriums were increasingly the expected solution for chronic illness. Patients with persistent conditions cycled through consultations, prescriptions, and rest cures at considerable expense — often with limited lasting benefit.

Sinclair was one of those patients. He suffered from chronic nervousness, persistent insomnia, and headaches so reliable he described himself as "never more than 15 minutes ahead of a headache." Over six to eight years, he sought help from physicians, surgeons, druggists, and sanatoriums. He estimated his total spending at approximately $15,000 — an extraordinary sum in 1911, equivalent to several hundred thousand dollars in today's purchasing power.

He tried vegetarianism. He tried raw food diets. He tried eating only meat. None of it provided a lasting solution.

How Sinclair Discovered Fasting

The turning point came when Sinclair encountered the idea of therapeutic fasting — the deliberate, complete abstention from food for a defined period. He was initially skeptical. The idea contradicted everything he had been told about the importance of nourishment during illness.

He undertook his first significant fast in a deliberate, careful way. The first four days were difficult: intense physical lassitude, dizziness when rising, a general heaviness. But his mind, he noted, remained surprisingly clear. In those first days he lost 15 pounds — a rapid loss he later interpreted as evidence of poor tissue quality accumulated from years of overeating and poor food choices.

Then something shifted. After the initial discomfort passed, the fast became manageable. He slept well throughout. He took cold showers and brief massages to address midday weakness. And when the fast ended, he moved to a careful recovery diet of warm milk, building up gradually over days.

The result? He described the weeks that followed as a kind of renaissance. Mental activity he had not experienced in years. Physical energy that surprised him. A sense of health he called "a new standard."

The Second Fast — and the Pattern That Emerged

Sinclair's second twelve-day fast produced results that would have seemed impossible to him before the first one. There was no weakness this time. He walked four miles every morning and did light gym work throughout. He lost nine pounds over eight days and found his mind "so active he read and wrote incessantly."

He wrote a play during that fast. He considered the work excellent.

This pattern — hardship in the first few days, followed by mental sharpness and physical stability — is something modern fasting researchers have documented extensively. The transition from glucose to fat metabolism, the rise of ketone bodies as brain fuel, the stabilisation of energy without blood sugar peaks and crashes: all of it maps onto what Sinclair described from personal experience in 1911.

The $15,000 Problem

The contrast Sinclair drew between his expensive years of medical treatment and the transformative effect of a simple fast was not subtle. He wrote that where medicine had cost him $15,000 over six to eight years with incomplete results, fasting had cost him almost nothing.

One of his readers — a man who had spent over $500 trying to recover on medicines — wrote back: "It cost me only thirty cents to use your method, and for that thirty cents I obtained relief a million-fold more beneficial."

This was not anti-medicine sentiment for its own sake. Sinclair acknowledged that medicine had its place. But he argued — and his reader survey of 277 cases largely supported him — that for many chronic conditions rooted in what he called "overeating and fermentation," no drug could accomplish what a properly conducted fast could.

Modern science has a different vocabulary for the same phenomenon. We speak of insulin resistance, low-grade inflammation, mitochondrial dysfunction, and gut microbiome imbalance — all of which can be meaningfully addressed by periodic fasting. Sinclair's framework of "fermentation and toxins" was imprecise by today's standards, but his practical conclusion — that the digestive system sometimes needs complete rest — has aged remarkably well.

What the 277 Reader Cases Showed

After Sinclair published his original fasting article in Cosmopolitan magazine, he received between 600 and 800 letters from readers who had tried fasting. Of these, 109 submitted detailed case reports describing 277 fasting episodes.

The conditions they reported as improved were wide-ranging: rheumatism, chronic headaches, asthma, insomnia, digestive disorders, nervous exhaustion, skin conditions, and kidney problems. One hundred of the 109 respondents reported benefit. Seventeen reported no benefit — and Sinclair noted that half of the non-benefiting cases involved fasting that was broken incorrectly, and half of the cases where improvement did not last involved returning immediately to poor eating habits.

The message Sinclair drew from these cases was consistent: the fast itself was not the whole story. Breaking it correctly and eating thoughtfully afterward was equally important.

The Connection to Modern Science

Sinclair's account pre-dates by decades the scientific tools that would eventually explain what he observed. We now know that:

• Autophagy — the cellular clean-up process Sinclair attributed vaguely to the "body consuming disease tissue first" — begins activating at around 17 hours of fasting and accelerates with longer fasting windows (Longo & Mattson, 2014, Cell Metabolism)
• Ketosis — the metabolic state Sinclair's fasters entered and which explains the mental clarity many described — is now documented precisely; the brain transitions from glucose to ketone bodies as its primary fuel during extended fasting (Cahill GF, 2006, Annual Review of Nutrition)
• Gut rest and repair — the "digestive rest" Sinclair described as the core mechanism of fasting healing aligns with modern research showing that fasting periods allow the intestinal lining to repair and the gut microbiome to reorganise

None of this means Sinclair's specific claims about "fermentation" or "clogged vessels" were scientifically accurate by modern standards. But the underlying practical insight — that the body has remarkable self-repair capacity when freed from the constant task of digestion — is supported by contemporary research.

What Sinclair's Story Teaches Us

The most important lesson from Sinclair's $15,000 medical journey is not that doctors are useless or that fasting cures everything. It is that chronic health problems often have lifestyle roots that no prescription can address.

His insomnia, his headaches, his nervous exhaustion — all of these were consistent with what we now recognise as symptoms of chronic inflammation and metabolic dysfunction, largely driven by the eating patterns of his time. The fast didn't cure him by magic. It gave his body the conditions it needed to restore function on its own.

More than a century later, millions of people are discovering the same thing through intermittent fasting — and the biology underlying the experience is now far better understood than it was in 1911.

For the complete modern guide to intermittent fasting — including what to eat, how to structure your window, and the science behind why it works — 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

How much did Upton Sinclair spend on medicine before discovering fasting? Sinclair estimated he spent approximately $15,000 over six to eight years on physicians, surgeons, druggists, and sanatoriums — equivalent to hundreds of thousands of dollars in modern purchasing power.

How long was Upton Sinclair's first major fast? His first significant fast lasted 12 days. He described the first four days as physically difficult, but then found his mind remarkably clear and eventually his strength returning. After the fast, he followed a milk diet for recovery.

Did Upton Sinclair recommend fasting for everyone? Sinclair was enthusiastic but not reckless. He recommended fasting with proper knowledge, adequate water intake, and careful refeeding afterward. He noted specific cautions — particularly for tuberculosis patients, for whom fasting might be inappropriate.

What did Sinclair eat after his fasts? He began with orange juice or grape juice in small quantities, then moved to warm milk, and eventually to fruits and nuts. He later found that broiled lean beef supported sustained intellectual work better than a purely plant-based post-fast diet.

Is The Fasting Cure still relevant today? As a historical document, yes. Many of Sinclair's practical observations — about the difficulty of the first few days, the mental clarity that follows, the importance of breaking a fast carefully, and the role of food quality after fasting — align closely with modern fasting research and practice.

Related Articles

• How Upton Sinclair discovered fasting and transformed his health
• The history of fasting as medicine: from 1911 to today
• What is The Fasting Cure? Upton Sinclair's 1911 guide to fasting

This article draws on historical research from 1911 and is for informational purposes only — not medical advice.

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