The necessary fasting duration depends on the purpose. For a blood test, fasting for 8 to 12 hours is typically required, although your doctor will provide specific instructions. MedlinePlus, WebMD However, to be considered a fast in scientific studies, at least 12 hours is necessary. Mass General Brigham, Medical News Today Some intermittent fasting methods involve longer fasts, ranging from 12 to 40 or more hours, but starting with 12 hours and progressing gradually under medical supervision is recommended. Healthline For reaping longevity and autophagy benefits, a 48-hour fast might be sufficient. Reddit r/fasting
Different Purposes, Different Durations:
- Blood Tests: 8-12 hours
- Scientific Definition of a Fast: At least 12 hours
- Intermittent Fasting: 12 hours or more, gradually increasing duration
- Longevity and Autophagy Benefits: 48 hours (as suggested by one source)
It's crucial to consult your doctor before starting any fasting regimen, especially if you have underlying health conditions.
