Fasting, mTOR, and Metabolic Rhythms

Series: Breathing, Body, Consciousness, and the Shifting of the Tensional Selves (Eus Tensionais)

Introduction — Brain Bee (first-person consciousness)

There are days when my body asks for expansion:
food, strength, presence, occupation.
On other days, it asks for the opposite:
less stimulus, less input, more inner silence.

If I listen, something reorganizes itself without effort.
If I insist on keeping everything the same, fatigue shows up first in the body—only later in the mind.

My body does not want constancy.
It wants rhythm.

mTOR: a building switch, not a permanent mode

mTOR (mechanistic Target of Rapamycin) is a central cellular metabolic pathway.
It coordinates processes of:

• growth,

• protein synthesis,

• repair,

• tissue expansion.

When mTOR is active, the body is in building mode.
This is essential for:

• hypertrophy,

• post-training recovery,

• wound healing,

• growth.

But mTOR was not made to stay “on” all the time.

Reducing mTOR is also a vital function

When mTOR activity decreases, other processes gain space:

• cellular recycling,

• metabolic reorganization,

• fine-tuning of systems,

• energy conservation.

This state is not loss.
It is deep maintenance.

Fasting, reduced stimulation, and metabolic pauses are not modern strategies.
They are ancestral rhythms of the living body.

Alternation is the rule, not the exception

Healthy life is sustained by alternation between:

• building ↔ reorganizing,

• expanding ↔ withdrawing,

• tensing ↔ releasing.

Keeping the body permanently in building mode:

• raises metabolic cost,

• reduces interoceptive sensitivity,

• narrows physiological variability.

Keeping the body permanently in restriction:

• impoverishes adaptation,

• reduces power,

• limits expression.

The problem is not one state.
It is the absence of switching.

Training, eating, and fasting as Tensional Selves

Each of these states supports a specific Tensional Self.

Intense training + feeding
→ Self of action, strength, expansion
→ mTOR active, sympathetic predominance

Light eating + active rest
→ Self of maintenance
→ autonomic balance

Controlled fasting + reduced stimulation
→ Self of reorganization
→ lower mTOR, higher interoceptive sensitivity

None of these Selves is “better.”
All are functional in the right time.

Breathing follows the metabolic state

These states do not appear only in metabolism.
They show up clearly in breathing.

In building mode:

• shorter breathing,

• higher tone,

• less expiratory pause.

In reorganization mode:

• looser breathing,

• expanded exhalation,

• greater variability.

Breathing does not create the metabolic state by itself,
but it sustains it and reveals it.

When rhythm is lost

In cultural contexts that demand:
constant productivity,
continuous eating,
permanent stimulation,
the body loses space to reorganize.

mTOR tends to remain elevated.
The autonomic system loses variability.
Interoception becomes dulled.

The body does not suffer from “too much growth.”
It suffers from the absence of pause.

Fasting is not a method—it is bodily language

Fasting does not need to be a rigid technique or a universal prescription.
It can be understood as bodily language asking for reorganization.

When imposed without listening, it becomes stress.
When it arises as a felt need, it becomes fine-tuning.

The body knows when to build
and when to let go.

Recognizing rhythm in your own body

No dogma. Observe:

• Is my body asking for food or for pause?

• Do I feel power, or saturation?

• Does my breathing match expansion or withdrawal?

• Can I alternate without guilt?

These answers reveal more than any protocol.

Closing

mTOR is neither villain nor savior.
It is one of life’s rhythms.

Training, eating, and fasting are not opposites.
They are different ways of existing in time.

When the body can alternate, it remains healthy.
When it gets stuck, it defends itself.

To learn how to live is to learn how to respect rhythm.

This text is part of the series Breathing, Body, Consciousness, and the Shifting of the Tensional Selves (Eus Tensionais), where different aspects of the same living system are approached from complementary angles.

References (post-2020)

Liu, G. Y., & Sabatini, D. M. (2020). mTOR at the Nexus of Nutrition, Growth, Ageing and Disease. Nature Reviews Molecular Cell Biology.
→ Core review on mTOR as an integrator of nutrients, growth, and cellular maintenance.

Saxton, R. A., & Sabatini, D. M. (2021). mTOR Signaling in Growth, Metabolism, and Disease. Cell.
→ Details how mTOR alternates between building states and metabolic reorganization.

Madeo, F., et al. (2020). Caloric Restriction and Fasting: Molecular Mechanisms. Science.
→ Describes cellular mechanisms activated when mTOR is reduced through fasting.

de Cabo, R., & Mattson, M. P. (2020). Effects of Intermittent Fasting on Health, Aging, and Disease. New England Journal of Medicine.
→ Links intermittent fasting to metabolic reorganization and systemic adaptation.

González, J. T., et al. (2021). Exercise, Nutrition and mTOR Signaling. Sports Medicine.
→ Integrates training, feeding, and mTOR activation in normal physiology.

Kim, Y. C., & Guan, K. L. (2021). mTOR: A Pharmacologic Target in Aging and Metabolic Diseases. Journal of Clinical Investigation.
→ Explores mTOR’s regulatory role and the importance of temporal modulation.

Longo, V. D., et al. (2021). Fasting and Fasting-Mimicking Diets. Cell Metabolism.
→ Discusses fasting as a tool for metabolic reorganization rather than a continuous state.

Dethlefsen, M. M., et al. (2022). Metabolic Flexibility and Cellular Adaptation. Frontiers in Physiology.
→ Connects metabolic alternation to adaptive capacity in living systems.