Reading on the web. Open in the Thier app for the full interactive version, progress tracking, and XP.
Open
The Science of Fasting
Your body's metabolic switch
After 12-16 hours without food, your body flips a metabolic switch — from burning glucose to burning fat and activating deep repair pathways.
12-16h
to flip the metabolic switch
Fact
What happens during a fast
0-4h: Digesting. 4-12h: Glycogen depletion. 12-18h: Fat burning + early autophagy. 18-24h: Peak autophagy + growth hormone surge. 24-48h: Deep cellular cleanup.
Try in app
Order the fasting timeline
Put these fasting milestones in chronological order.
This step is hands-on. Open the Thier app to try the full interaction.
True or false
True or False
Fasting slows down your metabolism.
Fasting significantly slows your metabolic rate
Short-term fasting (16-36h) actually slightly increases metabolic rate via norepinephrine release. Chronic calorie restriction is what slows metabolism.
Insight
Fasting vs calorie restriction
Fasting is NOT the same as eating less. Fasting triggers specific repair pathways (autophagy, sirtuins) that calorie restriction alone does not activate as strongly.
Takeaway
Key Takeaway
Strategic fasting activates repair pathways that are impossible to reach through diet changes alone. The 16:8 protocol is the easiest entry point.
Track your progress
Read the cards above, then mark this lesson complete to track your progress.
Reading without an account? Sign in to save progress across devices.