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.
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.
Order the fasting timeline
Put these fasting milestones in chronological order.
This step is interactive — open the Thier app to try it.
True or False
Fasting slows down your metabolism.
This step is interactive — open the Thier app to try it.
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.
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.