How Your Internal Organs Behave During Fasting

During a 36-hour fast, the body gradually "switches" from the metabolism characteristic of normal eating to a regenerative mode, functioning as internal energy.

During this period, not only the stomach empties, but the liver, fat tissue, brain, and immune system also undergo transformation.

 

How does metabolism change?

Initially, the body burns glycogen stored in the liver, then around the 12th-18th hour, ketosis begins: the body produces energy from fat in the form of ketone bodies.

After 30-36 hours, fat burning dominates, insulin levels remain low, and inversely, the level of fat-burning growth hormone rises.

 

What do the internal organs do?

From around the 16th hour, autophagy intensifies: cells begin to "clean up" their own worn-out, damaged parts, thus the liver, kidneys, and nervous system also regenerate.

This reduces chronic inflammation, helps improve insulin sensitivity, and enhances metabolism.

 

How does it affect the digestive system?

During fasting, the digestive system is less stressed, stomach acid production decreases, and the mucous membrane gets a "rest period."

This can alleviate reflux, reduce heartburn, and allow the gut flora to rebalance when eating gradually resumes after the fast.

 

What to pay attention to in practice?

A 36-hour fast is not suitable for everyone (e.g., it should be avoided without medical consultation in cases of low blood pressure, diabetes, thyroid problems, pregnancy).

It is important to drink plenty of fluids, replenish salt and electrolytes, and start with light, easily digestible food (e.g., soup, vegetables) after the fast so that the internal organs do not receive a sudden "shocking" load.

 

Here's all this humorously illustrated: