The 7 Levels of Fasting (Why Most People Never Reach Level 6)

The 7 Levels of Fasting (Why Most People Never Reach Level 6) | Body According to Science

Fasting triggers a structured metabolic progression rather than an immediate shift into fat burning or cellular repair. In the early hours, the body continues using circulating glucose while insulin levels gradually decline. As fasting extends, liver glycogen is broken down to maintain blood sugar, followed by activation of gluconeogenesis to produce glucose from non-carbohydrate sources. Simultaneously, hormonal changes increase lipolysis, releasing fatty acids from adipose tissue. With longer fasting durations, the liver converts these fatty acids into ketone bodies, which become an alternative energy source for the brain and other tissues. In more prolonged states, ketone utilization becomes more efficient and protein conservation mechanisms strengthen, although processes like autophagy remain variable and not precisely defined in humans. Overall, fasting reflects a time-dependent metabolic adaptation involving coordinated shifts in fuel use, hormone regulation, and energy conservation.

Supporting articles:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6520897/
https://www.ncbi.nlm.nih.gov/books/NBK22436/
https://www.ncbi.nlm.nih.gov/books/NBK279393/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8754590/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3106288/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2990195/

Видео The 7 Levels of Fasting (Why Most People Never Reach Level 6) канала Body According To Science