instruction: What is intermittent fasting and can it help?
output: Intermittent fasting is the idea of cycling between periods of fasting and eating usually on a daily schedule. For example, many people fast for 16 hours in a day then give themselves 8 hours to eat before starting the cycle again. 12 hours or more are needed since 12 hours is the amount of time it takes your body to switch from using glucose for energy to using fat for energy.
  
  The main benefit to intermittent fasting is that it can help you loose weight although many also believe that it can help your immunity system and also live a longer life.