Time-Restricted Eating

Mechanisms:

• Aligns eating with circadian metabolic rhythms (insulin sensitivity peaks in morning)
• Extends overnight fasting period, allowing cellular repair processes
• Reduces late-night eating when metabolism is least efficient
• Promotes autophagy (cellular cleanup) during extended fasting window
• Improves insulin sensitivity and glucose regulation

Key concepts:

• Circadian clocks exist in liver, pancreas, gut - they expect food at certain times
• Eating late at night disrupts peripheral clocks, impairing metabolism
• Same calories eaten at different times produce different metabolic responses
• "Metabolic jetlag" occurs when eating patterns conflict with light/dark cycles
• Consistency of eating window matters as much as length

Evidence base:

• Satchin Panda's mouse studies showed dramatic metabolic benefits
• Human RCTs show improvements in blood pressure, blood sugar, cholesterol
• Weight loss results mixed - some studies positive, some show no advantage over calorie restriction
• Benefits for metabolic health markers more consistent than scale weight
• Large myCircadianClock app study validated real-world feasibility

Limitations:

• Weight loss not guaranteed - still need calorie awareness
• Some recent RCTs showed no advantage over standard calorie restriction for weight loss
• Difficult for shift workers or irregular schedules
• Social challenges (dinner invitations, family meals)
• May not suit athletes with high caloric needs

Getting started:

1. Track current eating window - Most people eat over 15+ hours without realizing
2. Start with 12-hour window - Example: 7am-7pm (easy first step)
3. Narrow gradually - Drop to 10hr, then 8hr over several weeks
4. Consistent timing - Same window daily, including weekends
5. Stop eating 3 hours before bed - Critical for sleep and metabolism

Window options:

• 12 hours (e.g., 7am-7pm) - Minimal restriction, good starting point
• 10 hours (e.g., 8am-6pm) - Sweet spot for most people, sustainable long-term
• 8 hours (e.g., 10am-6pm or 12pm-8pm) - More aggressive, greater metabolic benefits
• 6 hours - Advanced, difficult to sustain, diminishing returns for most

Timing principles:

• Earlier windows better metabolically (breakfast > dinner)
• Don't skip breakfast and eat late - this is the worst pattern
• Coffee/tea (no calories) typically okay outside window
• Water always fine anytime

What counts as "eating":

• Any calories break the fast
• Black coffee/tea - usually fine (no cream/sugar)
• Bone broth - breaks fast
• Supplements - depends (check if caloric)

Risks:

• Overeating during window (defeats purpose)
• Undereating / inadequate nutrition
• Disordered eating patterns in susceptible individuals
• Blood sugar issues if diabetic (consult doctor first)
• May affect medication timing

Contraindications - do NOT do TRE if:

• History of eating disorders (anorexia, bulimia, binge eating)
• Pregnant or breastfeeding
• Type 1 diabetes (without medical supervision)
• Underweight or malnourished
• Children or adolescents
• Taking medications that require food at specific times

Warning signs to stop:

• Obsessive thoughts about food
• Binge eating during window
• Significant energy drops
• Sleep disruption
• Social isolation to maintain window

Key metrics to monitor:

• Eating window start/end times
• Window consistency (same times daily)
• Energy levels
• Sleep quality
• Weight (if goal)
• Hunger patterns (adapt over time)

Tracking methods:

• Simple log or notes app
• Zero app (fasting tracker)
• myCircadianClock app (Satchin Panda's research app)
• Any fasting app

Signs it's working:

• Stable energy throughout day
• Reduced late-night snacking urges
• Better sleep quality
• Morning hunger (healthy sign)
• Improved metabolic markers (if testing)

Timeline:

• Days 1-3: Hunger adjustment, may feel challenging
• Week 1-2: Hunger adapts, energy stabilizes
• Week 3-4: New normal, feels natural
• Month 2+: Metabolic benefits measurable

No products required - TRE is free.

Useful apps:

• Zero - Popular fasting tracker, free tier available
• myCircadianClock - Satchin Panda's research app
• Fastic - Fasting tracker with education
• Life Fasting - Simple tracker

Optional monitoring:

• Continuous glucose monitor (CGM) - See how eating window affects blood sugar
• Basic blood panel - Track fasting glucose, HbA1c, triglycerides over time

Key researchers:

• Satchin Panda - Salk Institute researcher who pioneered TRE research
• Krista Varady, PhD - University of Illinois, intermittent fasting researcher
• Valter Longo, PhD - USC, longevity and fasting researcher

Popularizers:

• Peter Attia - Discusses TRE in longevity context
• Andrew Huberman - Covers circadian eating on podcast

Online communities:

• r/intermittentfasting - Large active community
• r/fasting - More extreme fasting discussion
• Numerous Facebook groups

Common positive reports:

• "Simplified my relationship with food"
• "No more late-night snacking"
• "More energy, especially in morning"
• "Lost weight without counting calories"
• "Sleep improved dramatically"

Common complaints:

• "Hard to maintain socially"
• "Hungry for first week"
• "Didn't lose weight (without calorie attention)"
• "Morning coffee without cream is tough"

Pairs well with:

• Morning Sunlight - Both align with circadian rhythm; light in morning, food in morning
• Treadmill Desk - Post-meal walking regulates blood sugar
• Zone 2 cardio - Fasted morning cardio popular (though not required)

Timing considerations:

• Earlier eating window aligns with morning sunlight protocol
• Post-meal walking (treadmill desk) enhances glucose handling
• Stop eating 3hrs before bed for better sleep

Stacks with:

• All longevity interventions
• Sleep optimization protocols
• Metabolic health approaches