Intermittent Fasting Clinical Protocol

Choose protocol based on goals and lifestyle: 16:8 TRE (time-restricted eating): Fast 16 hours, eat within 8-hour window daily (easiest, most sustainable) - skip breakfast or dinner

18:6: More aggressive - 18 hour fast, 6 hour eating window

OMAD (one meal a day): 23:1 - advanced, one meal within 1-hour window

5:2 Diet: Eat normally 5 days, restrict to 500-600 calories 2 non-consecutive days

ADF (alternate-day fasting): Fast every other day (water/black coffee only) or 500 cal on fast days

24-36 hour weekly fast: Eat dinner, skip all meals next day, resume dinner following day (1-2x/week)

Circadian timing: Early TRE (eTRE) may be superior - eat breakfast and lunch, skip dinner (aligns with circadian insulin sensitivity - morning insulin sensitivity highest)

Traditional TRE (skip breakfast) easier for most

Fasting window: Water, black coffee, tea, zero-calorie drinks only - no cream, sugar, artificial sweeteners (controversial if breaks fast)

Electrolytes OK (salt, potassium) especially on longer fasts

Feeding window: Eat normally (no calorie restriction needed for 16:8 initially), but emphasize nutrient-dense whole foods for best results - avoid binging on junk food

Adaptation: Week 1-2 can be hungry (ghrelin spikes at usual meal times), usually adapts by week 3-4 - hunger hormone ghrelin becomes circadian entrained

Exercise timing: Fasted cardio OK (fat-burning), resistance training better in fed state (muscle protein synthesis), or adapt to fasted training over time

Breaking fast: No special protocol needed for 16:8 (unlike extended fasts) - eat normally, start with protein + vegetables if doing OMAD

Diabetes management: Monitor blood glucose closely first 1-2 weeks, reduce diabetes medications proactively (especially insulin, sulfonylureas - hypoglycemia risk) - work with prescriber

Medication timing: Take with meals if food-required, adjust timing to eating window

Supplements: Take during eating window (most absorb better with food)

Flexibility: Occasional longer or shorter windows OK (social events, travel) - consistency most days is what matters

Women/hormones: Some women do better with less aggressive fasting (14:10 instead of 16:8) - if menstrual cycle disruption, ease back

Autophagy: Peaks around 16-24 hours fasting (cellular cleanup) - longer fasts increase autophagy benefits

HGH: Growth hormone surges during fasting (muscle preservation despite no food)

Sleep: Don't eat close to bedtime (3+ hours before sleep) - improves sleep quality, growth hormone release

Hydration: Drink plenty during fasting - many mistake thirst for hunger

Monitor: Weight, waist circumference, fasting glucose/insulin (every 3 months), energy, hunger patterns, menstrual regularity (women), muscle mass (don't lose significant muscle)

Combine with: Low-carb or keto for synergy (ketones suppress appetite), Mediterranean diet for longevity

Progression: Start with 12:12, progress to 14:10, then 16:8 over 2-4 weeks if new to fasting

Long-term: Many maintain 16:8 indefinitely as lifestyle (not "diet") - ancestral eating pattern, sustainable