I know nothing about The Master Cleanse admittedly. But it 'canna change the laws of physics' as Scotty would say. Consume calories, even add taste to the body and you will effect the ketosis and the bodies ability to heal itself. Just because The Master Cleanse claims something doesn't mean it actually does it. If they are getting the body to produce ketones that is different from entering full ketosis where the body provides all of it's own nourishment and all of the vital organs are taken care of from them and every part of the body that can take part in cleaning the system and removing toxins does. If you are ingesting any food at all the body simply cannot go into full ketosis.