3 ms·See Nav_Panel's comment. Metabolic rate lowers after 60-72 hours.by superuser2 13y agoSee Nav_Panel's comment. Metabolic rate lowers after 60-72 hours.vidarh 13y agoHe specifically mentioned intermittent fasting, which is generally 16 hour fasted, 8 hour eating window, repeat.eru 13y agoOne-day-on, one-day-off is another common protocol.