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Filonov vs. Modern Biometrics

Dr. Sergei Filonov’s name gets dropped like scripture in dry fasting circles. His book Dry Medical Fasting: Myths and Reality is treated like gospel. He’s a medical doctor. He should know better.

But Filonov built his paradigm in an era before continuous biometric monitoring. Before we could track heart rate variability, stress scores, and resting heart rate in real-time. Before we could measure what was happening during the crisis instead of just interpreting symptoms.

The result: A framework based on observation and ideology rather than data and mechanism.


Filonov describes the acidosis crisis—days 3-5, elevated heart rate, extreme weakness—as the moment of “deep cleansing.” Your body temperature rises. You reek. Your tongue coats. You’re dizzy and weak.

He frames all of this as good signs. Evidence that acidosis-driven autolysis is eliminating “slag” and “toxins.”

The problem: This is correlation masquerading as causation.

Yes, autophagy occurs during a dry fast. Yes, ketones and metabolic byproducts increase. But the sympathetic overdrive—the spiking heart rate, the stress—isn’t evidence of “deeper” autophagy.

It’s evidence of mineral wasting and nervous system failure.

Filonov’s entire framework was developed without:

  • Continuous heart rate monitoring
  • Stress score tracking
  • Heart rate variability (HRV) data
  • Real-time biofeedback

He had subjective reports and clinical observations. Valuable, but incomplete. He couldn’t distinguish between suffering that correlates with metabolic benefits and suffering that causes metabolic damage.

Modern wearables reveal the truth: the crisis markers (↑RHR, ↑stress, ↓HRV) are independent of the beneficial markers (ketosis, lipolysis, autophagy initiation).


The Crisis Is Measurable—and Preventable

Section titled “The Crisis Is Measurable—and Preventable”

With a Garmin, Oura, or Whoop, you can watch the crisis develop in real-time:

Day 1-2: Metrics stable. Mild adaptation stress.

Day 3-4: RHR begins climbing. Stress scores drift upward. HRV drops.

Day 5+: Full crisis. RHR significantly elevated. Stress maxed. HRV collapsed.

This pattern is consistent across unsupplemented dry fasters. It’s not individual variation—it’s predictable physiology.

The mechanism: Aldosterone-mediated magnesium wasting creating a stress-magnesium vicious circle.

MetricTraditional (Filonov)Biometric-Guided (Magnesium Method)
RHR↑30-50% from baselineBaseline maintained
Stress ScoreMaximumLow throughout
HRVCollapsedStable
Subjective State”Extreme suffering""Clear, sharp, functional”
Metabolic BenefitsIdentical

The breakthrough: All the metabolic benefits Filonov attributes to the crisis occur independently of the stress markers.


Filonov is a medical doctor. So is Thomas Wolfe, another voice in the dry fasting space. Both are considered authorities.

Both completely ignore the role of magnesium—a cofactor in over 300 enzymatic reactions—in dry fasting physiology.

This isn’t an oversight. It’s negligence.

Magnesium is the central node for:

  • Nervous system regulation (GABA potentiation, NMDA blockade)
  • Energy production (ATP synthesis)
  • Autophagy function (lysosomal pH maintenance)
  • Stress response (HPA axis control)

When someone with medical training tells people to dry fast for 5-7 days without addressing the aldosterone-mediated magnesium dump, they’re recommending a protocol that guarantees metabolic crisis.


Filonov’s Framework:

  • Suffering = progress
  • Crisis = peak healing
  • Endurance = validation
  • No objective metrics

The Biometric Framework:

  • Metabolic state = progress
  • Crisis = preventable mineral wasting
  • Optimization = validation
  • Continuous objective metrics

The Russian school asks: “How much can you endure?”

The biometric approach asks: “How precisely can you optimize?”


Filonov contributed valuable observational work. He documented case studies. He pushed the boundaries of what was considered possible with extended dry fasting.

But we have better tools now. Continuous monitoring reveals that his core assumption—suffering equals healing—is physiologically incorrect.

The crisis doesn’t enhance autophagy. It arrests it.

Time to update the paradigm.


For the full biometric-driven protocol, see The Death of the Acidosis Crisis.


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