Ben Greenfield: The Truth About Fasting (Here’s What Actually Happens)

Key Takeaways

• 12-16 hour daily fast: Stop eating after dinner (e.g., 8 PM) and delay breakfast until 8 AM-12 PM.
• 24-hour fast 1-2x/month: Dinner-to-dinner fast (e.g., Saturday dinner to Sunday dinner).
• 3-5 day fasting-mimicking diet 4x/year: 500-800 calories/day, low protein, focus on juices/broths/electrolytes.
• Train smart while fasting: Prioritize yoga, sauna, walks over high-intensity workouts during extended fasts.
• Black coffee/tea allowed: Avoid adding calories (cream, sugar, butter) to maintain fasted state.

Supplements & Protocols Mentioned

• Electrolytes: Critical during multi-day fasts to prevent imbalances.
• Multivitamins: Recommended during prolonged fasting periods.

Products & Gear Mentioned

• Apollo/Sense devices: Vibration tools to improve sleep during fasting.
• New Calm/Sleep Stream apps: Use soundscapes to enhance relaxation.

Notable Quotes

“Fasting for longer than 16 hours is where cellular cleanup and longevity benefits start to kick in.”

“Coffee’s caffeine can shift your body into higher fat burning—just don’t add calories.”

Bottom Line

Start with 12-16 hour overnight fasts, progress to 24-hour monthly fasts, and consider quarterly 3-5 day low-calorie periods. Pair with low-intensity movement and prioritize electrolyte balance.

Watch the Full Video