Chapter 3: What Happens to Your Body When You Fast?

The idea of going without food for hours (or even days) might sound extreme, but here’s what’s actually happening inside your body:

First 12 Hours: The Body Uses Stored Sugar

When you stop eating, the body first burns through its glycogen (stored sugar) for energy. This is why many people feel hunger pangs at first—your body is looking for its usual fuel.

12-24 Hours: Fat Burning Begins

Once glycogen runs out, the body starts burning fat for energy. This is called ketosis, where the body switches from burning sugar to burning fat.

24-48 Hours: Autophagy Kicks In

Now, the body starts breaking down old, damaged cells and using them for energy. This is a natural cleansing process that gets rid of weak cells and stimulates new cell growth.

48+ Hours: Deep Cellular Repair

At this point, fasting triggers massive health benefits:

Growth hormone increases, preserving muscle and burning fat.

Insulin levels drop, making the body more sensitive to insulin (reversing diabetes).

Inflammation decreases, improving conditions like arthritis and skin issues.

The immune system regenerates, producing fresh white blood cells.