What is the difference between IF and Prolonged Fasting (PF)?

The difference between intermittent fasting (IF) and prolonged fasting (PF) like ProLon is that, whereas IF involves fasting intervals anywhere from 12 to 24 hours, PF generally refers to fasts lasting longer than 48 hours. With the shorter fasting intervals characteristic of IF, the body crosses the threshold from using glucose from the most-recent meal to using its own internal energy stores  and doesn't trigger a true cellular stress-resistant fasting state. With the longer fasting intervals of PF, the main source of fuel switches to fat, which is part of the reason PF is such an effective way to melt those inches off your waistline, and your cells enter a fasting clean-up state.