Intermittent fasting is when we do not eat anything for 16-18 continuous hours in a day and eat only during the remaining 6-8 hours. Our body can heal when it is resting and gets a break from digestion. So, this break in eating gives the digestive system time to rest, this is how nature meant it to be. It also allows the body to clean itself.
But putting only good quality, nutrient-dense food in our body will reduce the need to compulsively cleanse the body repeatedly. While 16 hours of fasting is ideal, you can even start from where you are, that is the natural break in eating during sleep, and gradually increase it till the time period you are comfortable with. However, avoid starting a routine that you find hard or cannot sustain.