This Podcast Will Kill You

Ep 201 Poop Part 2: Flushed away

February 17, 2026

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  • The historical management of human waste has cycled between viewing excrement as a valuable resource (e.g., Minoans, ancient China/Japan nightsoil) and viewing it as a dangerous waste product requiring immediate removal (e.g., Great Stink of London), with the latter view dominating modern sanitation. 
  • Technological advancements like the Minoan flushing toilets and the Roman *Cloaca Maxima* solved immediate local sanitation crises by moving waste downstream, often leading to larger, collective pollution problems in rivers and seas. 
  • Constipation, defined by hard stools, straining, or incomplete evacuation, is often managed with osmotic laxatives that draw water into the stool, while dietary fiber is crucial for prevention by increasing bulk and feeding the gut microbiome, rather than treating acute constipation. 
  • Adequate fiber intake is crucial for gut health, potentially preventing inflammatory diseases and colon cancer, while constipation can lead to painful conditions like diverticulosis and hemorrhoids. 
  • Diarrhea poses significant risks due to rapid water and electrolyte loss, with chronic diarrhea defined as loose stools in at least 25% of bowel movements for three weeks or more. 
  • Probiotic efficacy is highly variable due to lack of regulation and strain specificity, making Fecal Microbiota Transplants (FMT), currently FDA-approved for recurrent *C. diff* infection, a more comprehensive approach to restoring gut microbiome architecture. 

Segments

Faraday’s Thames Report
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(00:01:06)
  • Key Takeaway: M. Faraday documented the River Thames in 1855 as an opaque, foul-smelling sewer, warning that neglecting the condition could lead to future disaster.
  • Summary: Faraday described the river water as an opaque, pale-brown fluid so dark that white card pieces dropped into it became indistinguishable within an inch of the surface. The smell was comparable to that rising from street gully holes, leading him to conclude the entire river was a ‘real sewer.’ He urged those in power to address the issue before a hot season brought proof of their carelessness.
Poop Disgust and Evolution
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(00:08:38)
  • Key Takeaway: The universal human and animal aversion to feces is evolutionarily ingrained due to the risk of pathogens, a concept Charles Darwin recognized as one of the six universal emotions.
  • Summary: The inherent disgust toward poop is not a modern or Victorian construct but an ancient survival mechanism to avoid pathogens. This aversion is observed across many animal species, which often establish latrines far from living or grazing areas. This instinct contrasts with the historical utility of poop as a nutrient source.
Ancient Waste Management
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(00:13:03)
  • Key Takeaway: The Minoan civilization (c. 1700 BCE) utilized advanced, still-functioning rainwater-flushed toilets connected to sewers that emptied into the sea, predating later Roman systems.
  • Summary: As human settlements grew, waste management became a problem, leading the Minoans to develop flushing toilets and drainage systems that carried waste into streams and the sea. The Harappan civilization also employed deep gutters with removable covers for drainage. Ancient Rome managed its massive waste via the Cloaca Maxima, primarily built to drain swamps, which also carried sewage into the Tiber River.
Medieval and Early Modern Poop Handling
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(00:25:31)
  • Key Takeaway: Medieval European sewage management prioritized moving waste away from the individual, often resulting in moats becoming cesspools, while laws were frequently passed to curb public defecation in cities.
  • Summary: The wealthy often directed waste from private latrines into moats, while the poor used outdoor pits or chamber pots emptied with a warning cry into the streets. The sheer volume of waste led to laws, such as one in Berlin (1671) requiring peasants to remove piles of poop near a church. The occupation of ’nightmen’ arose to collect waste, sometimes storing it in pits where they experimented with dissipation methods.
Invention of the Flush Toilet
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(00:30:14)
  • Key Takeaway: Sir John Harrington invented the first modern flushing toilet, ‘Ajax,’ in 1584, featuring valves and a cistern, though its widespread adoption was later popularized by Thomas Crapper.
  • Summary: Harrington’s invention was adopted by Queen Elizabeth I, but the technology only became a status symbol centuries later through the marketing efforts of plumber Thomas Crapper. This widespread adoption led to the problem of moving individual cesspits into rivers, culminating in the Great Stink of London in 1858.
The Great Stink and Sewer Solutions
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(00:33:34)
  • Key Takeaway: The Great Stink of 1858 galvanized Londoners into building Joseph Bazalgette’s massive, intricate sewer system, despite the estimated fertilizer value of the waste being discarded into the Thames.
  • Summary: The intense stench of the Thames, caused by the fermentation of sewage from nearly 3 million people under a hot sun, spurred action, partly driven by the miasma theory of disease spread. Although the waste was estimated to be worth £178 million today as fertilizer, England chose to flush it away, a sentiment Victor Hugo later criticized regarding Paris’s sewers.
Nightsoil Value vs. Modern Waste
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(00:36:23)
  • Key Takeaway: Cultures like those in Japan and China historically valued nightsoil as a critical fertilizer, adjusting rent based on its production, a practice that declined in the 20th century with commercial fertilizer and germ theory.
  • Summary: The need for fertilizer, especially in land-limited regions like Japan, made human and animal excrement a commodity, sometimes commanding a price higher than gold in imperial decrees. Composting and fermentation were key processes used to reduce pathogens before applying the manure to crops. The rise of germ theory shifted the perception of poop from a resource to an enemy to be feared and flushed.
Modern Nutrient Redistribution Crisis
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(00:42:20)
  • Key Takeaway: Modern sewage systems solve immediate proximity problems but create a new crisis by redistributing essential nutrients like phosphorus and nitrogen from agricultural areas into the oceans, causing algal blooms and ecosystem collapse.
  • Summary: The current system separates nutrients from where food is grown; livestock manure leaches near farms, and flushed human waste ends up in waterways far from the original source. This nutrient imbalance leads to environmental consequences like barren farmland and ecosystem decay. Innovators are now working on solutions like efficient toilets and transforming waste into fuel or fertilizer.
Individual Health Indicators: Constipation
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(00:46:31)
  • Key Takeaway: Constipation is clinically defined by hard/lumpy stools, straining, or incomplete evacuation occurring in over 25% of bowel movements, and it can contribute to secondary issues like diverticulosis.
  • Summary: Constipation can result from slow gut transit time, often linked to low fiber intake or sedentary lifestyles, or from dysmotility disorders like Hirschsprung’s disease. Treatments include osmotic laxatives (like PEG) that hold water in the stool, and stimulant laxatives that encourage muscular contractions, though stool softeners lack strong supporting data.
Fiber’s Role in Gut Health
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(00:54:39)
  • Key Takeaway: Dietary fiber, divided into soluble and insoluble types, is essential for preventing constipation by bulking stool and feeding the gut microbiome to produce beneficial short-chain fatty acids.
  • Summary: Soluble fibers (like psyllium) and insoluble fibers (like wheat bran) work together to improve stool transit time and bulk. Fermentable fibers are broken down by gut bacteria, producing short-chain fatty acids that colon cells use for energy. Low-fiber diets are suspected to contribute to the rising incidence of conditions like colon cancer.
Fiber’s Role in Health
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(00:56:43)
  • Key Takeaway: Low-fiber diets are potentially linked to the increasing incidence of colon cancer, especially early-onset cases.
  • Summary: Fiber is vital for the gut microbiome and may help prevent the worsening of inflammatory diseases. The recommended daily fiber intake in the U.S. is 28 to 35 grams. Whole foods are preferred for fiber intake to ensure a beneficial mix of types.
Constipation Complications
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(00:57:08)
  • Key Takeaway: Constipation significantly increases the risk of developing diverticulosis, where outpouchings in the gut wall can become infected or bleed.
  • Summary: Constipation is painful and can cause secondary issues like diverticulosis, which involves small, infected pouches in the sigmoid colon wall. Straining due to constipation also contributes to the development of hemorrhoids. Anal fissures, which are painful tears in the anal skin, are another consequence of straining.
Diarrhea Risks and Types
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(01:04:49)
  • Key Takeaway: Diarrhea, especially chronic diarrhea lasting over three weeks, puts individuals at high risk for dehydration and electrolyte imbalance due to high water and protein loss.
  • Summary: Acute diarrhea is defined as three or more loose stools in 24 hours, while chronic diarrhea meets this frequency threshold for at least three weeks. The composition of diarrheal stool (e.g., fatty vs. watery) depends on the underlying cause, such as infection or lack of a gallbladder affecting fat digestion.
Understanding IBS
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(01:08:03)
  • Key Takeaway: Irritable Bowel Syndrome (IBS) is diagnosed based on recurrent cramping abdominal pain associated with changes in stool frequency or consistency for at least three months.
  • Summary: IBS is distinct from Inflammatory Bowel Disease (IBD), which is an autoimmune inflammatory condition. IBS is believed to be partly a disorder of the gut-brain axis, involving neurotransmitters and intestinal dysmotility (moving too fast or too slow). Visceral hypersensitivity means nerve endings in the gut feel more pain than they should.
Probiotics and Prebiotics Hype
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(01:11:58)
  • Key Takeaway: Despite widespread use, there is very little data supporting the benefit of probiotics for most conditions outside of antibiotic-associated diarrhea due to lack of regulation and study heterogeneity.
  • Summary: Prebiotics are often marketed as distinct but are usually just fiber or non-digestible sugars. Probiotics face challenges because few bacterial strains have proven efficacy, and supplements lack regulation regarding live bacteria count and survival through the digestive tract. Only a handful of species, like certain Lactobacillus and Bifidobacterium, have some supporting data.
Fecal Transplants Explained
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(01:16:07)
  • Key Takeaway: Fecal Microbiota Transplant (FMT) involves transferring a healthy person’s entire gut microbial community to treat disease, with FDA-approved oral capsules now available for recurrent C. diff infection.
  • Summary: FMT aims to restore the entire architecture of the gut microbiome, which isolated probiotic strains likely cannot achieve. The procedure can be administered via colonoscopy, NG tube, or increasingly, as oral capsules. Research is promising for using FMT to treat conditions like IBD and IBS, though long-term stability of the transferred community is still being studied.
Further Reading Recommendations
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(01:19:44)
  • Key Takeaway: Several books offer deeper dives into the history of waste management and specific gastrointestinal issues like constipation.
  • Summary: Recommended reading includes The Other Dark Matter by Linda Zeldovich on turning waste into wealth, and Constipation Nation by Dr. Fong for detailed information on constipation. A 2017 paper titled ‘The Hydrodynamics of Defecation’ provided data suggesting that spending time on the phone while on the toilet increases hemorrhoid risk.