My way? →

Published March 10  ·  All posts on Mar 10  ·  

For me, all these complex valences reach their peak in one song. And you know which one I’m talking about.

Ted Gioia, from “My Way” or the Highway?

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There was a time—20 years ago, I’d say—when I sang along. It was of course aspirational— or— I’m looking for a word; not quite “aspirational.” I was singing along as if the song in any way represents my actual story. In reality, I’m only acting as if I’d actually tried to do even a few of the things expressed, let alone actually accomplished all the things expressed. Is that posturing? …playacting? …attempting to borrow someone’s bravado?

I’m going to go with: self-deception.

There was a time, not too long ago, when I sang along in self-deception. Now the song reminds me that I’ve never actually even tried to do anything… let alone accomplished anything worth singing about.

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Like letter-writing? →

Published March 9  ·  All posts on Mar 9

There are broadly two types of sources we identify when studying history: narrative sources and relics […] The former are things designed to convey something to future generations, […] Relics [sic] the other hand were not intended for future generations. They do not have a “transmission intent”. While they often hold true to the beliefs of the person producing them they tend to have little to no large-scale bias in recording history. They are also excellent records equivalent to oral history and can serve as both primary sources and secondary sources that are closer to an original event than subsequent scholarly literature.

~ Venkatram Harish Belvadi, from Relics of the future

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I’ve now been typing away on this blog for fifteen years and what I have posted here has varied wildly in that time.

While it has occurred to me to wonder what happens to the blog after I die, it had never occurred to me to wonder if there might be actual value to historians here.

I’m honestly not sure what to do with that. Do I keep posting? Do I close the garage door?

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Part 6: The Brain →

Published March 4  ·  All posts on Mar 4  ·  

I’ve been doing 16:8 intermittent fasting for years and recently started 48-hour fasts — dropping about three pounds each fast, gaining one or two back, and trending steadily downward. I wanted to understand what the research actually says about what I’m doing to myself, so I worked with Claude (Anthropic’s AI) to produce this series. I set the structure, chose the topics, pushed back on claims that felt hand-wavy, and guided the editorial tone. Claude did the writing and research synthesis. My curiosity driving Claude’s research and prose.

Mental Clarity, BDNF, and Ketone Fuel

Research brief — what happens in the brain during extended fasting. The subjective experience of mental clarity is real and widely reported; the science behind it is more complicated than the popular narrative suggests.

The Clarity People Report

Many people describe a distinct shift during extended fasting — typically somewhere after the 24–36 hour mark — from brain fog to unusual mental clarity. This is one of the most consistently reported subjective experiences of fasting, across cultures and contexts. It’s real. The question is why.

Three candidate explanations, not mutually exclusive:

  1. Ketone metabolism — the brain runs efficiently on beta-hydroxybutyrate (BHB)
  2. BDNF upregulation — fasting may increase brain-derived neurotrophic factor
  3. Stable fuel supply — no more blood sugar fluctuations from meals

The first and third have strong physiological grounding. The second is where the science gets shaky.

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Part 5: Inflammation and Immune Renewal →

Published March 4  ·  All posts on Mar 4  ·  

I’ve been doing 16:8 intermittent fasting for years and recently started 48-hour fasts — dropping about three pounds each fast, gaining one or two back, and trending steadily downward. I wanted to understand what the research actually says about what I’m doing to myself, so I worked with Claude (Anthropic’s AI) to produce this series. I set the structure, chose the topics, pushed back on claims that felt hand-wavy, and guided the editorial tone. Claude did the writing and research synthesis. My curiosity driving Claude’s research and prose.

Inflammation and Immune Renewal

Research brief — how fasting reduces systemic inflammation and primes the immune system for regeneration. Two distinct but related mechanisms.

Inflammation Reduction

Jordan et al. 2019 — Stefan Jordan, Navpreet Tung, and colleagues at the Icahn School of Medicine at Mount Sinai, led by Miriam Merad. Published in Cell, 178:1102-1114. (1)

This study directly tied caloric intake to the circulating inflammatory monocyte pool — a key driver of systemic inflammation.

What they found:

  • Short-term fasting reduced monocyte metabolic and inflammatory activity and drastically reduced the number of circulating monocytes
  • The mechanism: fasting activates AMPK in hepatocytes (liver cells) and suppresses systemic CCL2 production via PPARα, which reduces monocyte mobilization from bone marrow
  • Fasting improved chronic inflammatory diseases without compromising emergency immune mobilization during acute infection — the immune system’s ability to respond to real threats remained intact
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Part 4: Hormonal Shifts →

Published March 4  ·  All posts on Mar 4  ·  

I’ve been doing 16:8 intermittent fasting for years and recently started 48-hour fasts — dropping about three pounds each fast, gaining one or two back, and trending steadily downward. I wanted to understand what the research actually says about what I’m doing to myself, so I worked with Claude (Anthropic’s AI) to produce this series. I set the structure, chose the topics, pushed back on claims that felt hand-wavy, and guided the editorial tone. Claude did the writing and research synthesis. My curiosity driving Claude’s research and prose.

Growth Hormone and Insulin Sensitivity

Research brief — the two best-evidenced hormonal responses to extended fasting, with direct human measurements.

Growth Hormone Surge

Human growth hormone (HGH) secretion increases substantially during fasting. This is among the best-measured effects of fasting in humans — researchers have drawn blood every 5 minutes over 24-hour periods to capture the pulsatile secretion patterns.

Ho et al. 1988 — Examined 24-hour GH secretion patterns in six normal adult men during fed and fasting states (day 1 and day 5 of a 5-day fast). Found that fasting enhances GH secretion through both increased pulse frequency and amplitude. (1)

Hartman et al. 1992 — The definitive study. Nine normal men, blood sampling every 5 minutes over 24 hours. Found a *-fold increase in 24-hour endogenous GH production during a two-day fast, mediated by increased secretory burst frequency and amplitude. Notably, IGF-1 concentrations were unchanged after 56 hours of fasting. (2)

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Part 3: Cellular Cleanup →

Published March 4  ·  All posts on Mar 4  ·  

I’ve been doing 16:8 intermittent fasting for years and recently started 48-hour fasts — dropping about three pounds each fast, gaining one or two back, and trending steadily downward. I wanted to understand what the research actually says about what I’m doing to myself, so I worked with Claude (Anthropic’s AI) to produce this series. I set the structure, chose the topics, pushed back on claims that felt hand-wavy, and guided the editorial tone. Claude did the writing and research synthesis. My curiosity driving Claude’s research and prose.

Autophagy

Research brief — what autophagy is, what the evidence actually shows, and where the common claims outrun the science.

What Autophagy Is

Autophagy — from Greek auto (“self”) and phagein (“to eat”) — is the process by which cells degrade and recycle damaged organelles, misfolded proteins, and dysfunctional mitochondria. Think of it as cellular housekeeping: damaged parts get broken down and the raw materials get repurposed for repair and new construction.

Yoshinori Ohsumi won the 2016 Nobel Prize in Physiology or Medicine for discovering the genetic mechanisms of autophagy. Working in baker’s yeast in the early 1990s, he identified the genes essential for the process. The mechanisms are highly conserved across species including humans. (1)

The molecular trigger is well-understood: nutrient deprivation suppresses insulin and mTOR signaling and activates AMPK — all of which are upstream regulators of autophagy. The logical chain from “fasting → reduced insulin/mTOR → autophagy activation” is mechanistically solid. Disrupted autophagy has been linked to Parkinson’s disease, type 2 diabetes, Alzheimer’s, certain cancers, and many infections. (2)

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Part 2: Getting Into Fasting →

Published March 4  ·  All posts on Mar 4  ·  

I’ve been doing 16:8 intermittent fasting for years and recently started 48-hour fasts — dropping about three pounds each fast, gaining one or two back, and trending steadily downward. I wanted to understand what the research actually says about what I’m doing to myself, so I worked with Claude (Anthropic’s AI) to produce this series. I set the structure, chose the topics, pushed back on claims that felt hand-wavy, and guided the editorial tone. Claude did the writing and research synthesis. My curiosity driving Claude’s research and prose.

Routines, Scenarios, and What to Expect

Research brief — the practical onramp. 16:8 IF as a starting point, Craig’s specific eating window, extended fasting scenarios anchored to a weekly rhythm, and what keto flu actually is.

Start With 16:8

You may want to start by getting into 16:8 intermittent fasting — an 8-hour eating window and 16-hour fast — before attempting anything longer.

Is this actually supported? Honestly, no one has studied whether practicing 16:8 first makes longer fasts easier. It’s conventional wisdom without a clinical trial behind it. But the physiological rationale is sound: regular time-restricted eating develops metabolic flexibility — the ability to switch between glucose and fat/ketone oxidation. Someone who does this daily would be expected to enter ketosis faster and with less discomfort during an extended fast. And the practical experience of managing hunger, learning your body’s signals, and knowing what electrolyte depletion feels like are real benefits of prior fasting experience, even if unstudied. (1)

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Part 1: Why Fasting Works →

Published March 4  ·  All posts on Mar 4  ·  

I’ve been doing 16:8 intermittent fasting for years and recently started 48-hour fasts — dropping about three pounds each fast, gaining one or two back, and trending steadily downward. I wanted to understand what the research actually says about what I’m doing to myself, so I worked with Claude (Anthropic’s AI) to produce this series. I set the structure, chose the topics, pushed back on claims that felt hand-wavy, and guided the editorial tone. Claude did the writing and research synthesis. My curiosity driving Claude’s research and prose.

The Big Picture

Research brief — general overview of fasting benefits. The most “hand-wavy” of the series: frameworks, history, and the broad case for why not eating is doing something useful.

The Metabolic Switch

The overarching framework for understanding fasting benefits comes from Mark Mattson’s “metabolic switch” concept, reviewed comprehensively in a landmark 2019 NEJM paper co-authored with Rafael de Cabo. (1)

The core idea: when you stop eating for long enough, the body shifts from glucose-based to ketone-based energy. This isn’t just a fuel swap — it’s a stress response that activates adaptive cellular pathways. The metabolic stress of fasting triggers increased expression of antioxidant defenses, DNA repair, protein quality control, mitochondrial biogenesis, and autophagy. These protective mechanisms outlast the fast itself — a hormetic effect where controlled stress leaves the system stronger.

This is the thread that connects the individual benefits explored in the rest of this series: better insulin sensitivity, growth hormone surges, inflammation reduction, cellular cleanup, and (possibly) neurological benefits all flow from this same metabolic switch.

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Temenos, part 2 →

Published March 2  ·  All posts on Mar 2  ·  

Today one can conduct an interview on the phone or via Skype, but ideally, in order to truly foster reciprocities of rapport and insight in a meeting, one requires a live countenance and a quiet physical space-like the ancient Greek temenos, with its sacred enclosure or holy grove or magic circle— in which an interview can live and flourish.

Jonathan Cott, xiv, from Listening: Interviews, 1970-1989

There’s this word, again!

I’d spotted it previously… and it came to mind during Steve Heatherington’s monthly podcast call. I was reminded of it by his discussion of telic. But I couldn’t exactly remember the the word temenos at first. I am certain I first heard it mentioned in an episode of Boston Blake’s Mythic podcast, but I couldn’t find a reference to a specific episode (on my blog or by searching.) Then I realized the word appears in the Introduction to a terrific book. Which was also literally sitting on my desk… a crazy confluence of events.

When I first encountered it, I’d not thought of it in the context of what we podcast hosts do for our guests. But Cott makes it crystal clear.

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Your current reality →

Published March 1  ·  All posts on Mar 1  ·  

You must never confuse faith that you will prevail in the end—which you can never afford to lose—with the discipline to confront the most brutal facts of your current reality, whatever they might be.

James Stockdale

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