Been intermittent fasting (one meal a day) since 10/3. Not a problem for me since I am keto and already fat adapted. I was able to work up to controlling the hunger pangs.
I switched over to a juice cleanse on the 15th. I was pretty lethargic the first day, but I have felt very good since then. I think the slow build up and transition to less and less food is what helped me not have to experience food withdawls or detox symptoms.
I also am utilising colon cleanse methods to make sure the toxins are leaving and not causing "flu like" symptoms from the detox.

Long story stort,
If done right you can feel great...if done wrong, pain.