Standalone diets (carb-heavy, protein-dominant, or fat-focused) work—we can see how they operate in terms of energy metabolism—but why they work, in a deeper physiological or evolutionary sense, is a more layered question:

🧬 HOW They Work — The Mechanistic View:

Each macronutrient-dominant diet taps into a specific metabolic pathway:

High-Carbohydrate Diet (CHO → Glycolysis):

Glucose is the primary energy substrate; insulin is high; glycogen stores are full; ideal for short bursts of energy. FGF-21 may be suppressed unless there's caloric restriction.

High-Protein Diet (Gluconeogenesis → GNG):

The body converts amino acids into glucose, slower than glycolysis. Often high in satiety signals (PYY, GLP-1). Can stimulate FGF-21 in some settings, especially under low-carb conditions.

High-Fat/Ketogenic Diet (Lipolysis → Ketosis):

The liver produces ketone bodies (e.g., beta-hydroxybutyrate) used by brain and muscles. FGF-21 levels usually increase as a starvation/fasting hormone.

So that's how—but...

🧠 WHY They Work — The Deeper Inquiry:

1. Metabolic Flexibility and Hormetic Stress

Each diet acts as a metabolic stressor—it shifts the body out of homeostatic predictability. This stresses the system just enough to trigger:

Autophagy

Mitochondrial biogenesis

AMPK activation

Hormonal optimization (e.g., increased adiponectin, modulation of FGF-21)

Like exercise, the mild metabolic discomfort can lead to systemic benefits via hormesis.

2. Evolutionary Niche-Specific Adaptation

Different humans thrived in different ecological niches:

Arctic and steppe nomads (e.g., Inuit): Fat-dominant diets

Tropical fruit-gatherers: Carb-heavy diets

Pastoralists or survivalist warriors: Protein-heavy periods

Each diet mimics a seasonal or survival-based metabolic state, triggering ancient genetic programs that may enhance healing, focus, and fat loss depending on the internal terrain and environment.

3. Simplicity & Compliance

Often, the success lies not in the biochemistry but the behavioral and psychological clarity:

Fewer food choices = less decision fatigue

Clear rules = easier adherence

Less mixing = improved gut health and insulin control

A standalone diet imposes a form of monodietic discipline, which may paradoxically help correct modern metabolic chaos.

4. Microbiome Reset or Shift

Each diet radically reshapes the gut microbiota—this in turn affects:

Inflammation

Neurotransmitter production

Immune tone

Energy extraction from food

You’re not just feeding yourself. You’re feeding your microbial consortium—and different ones thrive under different macronutrient dominances.

Final Thought:

We know the metabolic mechanisms. But why these diets work may boil down to mimicking ancient stressors, simplifying inputs, resetting internal rhythms, and triggering adaptation pathways lost in our surplus-driven world.

In this light, stand-alone diets don’t just feed the body—they signal the genome. They’re not just nutrition—they’re code