At what fasting duration do YOU feel the biggest mental clarity boost?

16 hours is the sweet spot for most people

Mental clarity kicks in once insulin stays low long enough

14–16 hours feels sharp without stress

Past 18 hours returns diminish for me

Around 15 hours calm alert clean energy.

20 hours helps some hurts others.

Sleep quality the night before matters more than length

16:8 gives focus without brain fog

Over-fasting blunts focus long term

Mental calm hunger suppression

Stress ruins clarity faster than food does