Fasting Tier	Hours Fasted	Eating Window	Difficulty	Main Benefits	Suggested Frequency	Best For
Tier 0 – Fed State	0–8 hrs	16+ hrs	🟢 Very Easy	Constant digestion, minimal fat burn, no autophagy	Daily	Muscle gain, beginners, high activity levels
Tier 1 – Light Fast	8–12 hrs	12–16 hrs	🟢 Easy	Blood sugar stabilization, digestive reset begins	Daily	General health, digestion, sleep support
Tier 2 – Fat Burn	13–15 hrs	9–11 hrs	🟡 Mild	Fat adaptation, improved metabolic flexibility	4–6x/week	Fat loss, energy balance
Tier 3 – Autophagy	16–18 hrs	6–8 hrs	🟠 Moderate	Cell cleansing, growth hormone boost, reduced inflammation	3–5x/week	Anti-aging, body recomposition
Tier 4 – Deep Fast	19–22 hrs	2–5 hrs	🔴 Hard	Deep fat burn, insulin sensitivity, peak focus	2–3x/week	Plateaus, brain clarity, gut reset
Tier 5 – Warrior / OMAD	23+ hrs	1 hr or less	🔴🔴 Advanced	Full autophagy, hormonal optimization, gut reset, longevity boost	1–2x/week	Longevity, deep cleanse, spiritual clarity

Pro Tips & Cautions Table

Tier(s)	Cautions / Warnings	Support Tools & Tips
Tier 0–1	Overeating possible; no metabolic challenge	Eat whole foods, avoid snacking all day
Tier 2	Light hunger may occur; ease into longer fasts	Stay hydrated, black coffee or green tea OK
Tier 3	Mental clarity kicks in, but energy dips may happen	Electrolytes (sodium, magnesium), walk/light movement
Tier 4	Can feel intense at first; may interfere with workouts	Bone broth, salt water, light stretching, break fast with nutrient-dense meal
Tier 5	Not for beginners; risk of refeeding symptoms if broken incorrectly	Lemon water, raw honey post-fast, prioritize protein + minerals

Note: William's personal strategy = Tier 3 baseline, with Tier 4–5 rotation Mon–Fri. Weekends flexible. Solid mix of structure and freedom.