I did the first cleanse they had at the end of April. It lasted 7 days with 3-4 days of prep and 7-14 days of food re-introduction. During the prep, you gradually cut down or eliminate those foods that often cause sensitivity in the body and completely eliminate them during the cleanse. Foods such as dairy, eggs, nuts, bread, pasta, rice, coffee, certain meats, soft drinks, sugar and all processed foods. They provide lots of recipes for meal planning and a private Facebook page where you can post questions, get support and share experiences with other "cleansers". There is plenty of food options and I never felt hungry or deprived. It is not about cutting calories or drinking only liquids but rather eating real whole food that is good for your body which allows your liver to detox and ease digestion. Most participants reported that they felt great, lost weight and/or lost their cravings for sugary, junky processed food. The gurus explain the science behind the program so it makes sense and are always available to answer questions along the way. After the 7 days, you gradually add back the eliminated foods to see how your body reacts. For example, one day you add back eggs and suddenly feel gassy, bloated etc.. that may indicate a food sensitivity. Of course, you never add back sugar or processed junk because it doesn't offer any nutritional value to your body. Usually the Gurus have a free informational webcast that you can listen to via phone or internet which highlights the program so I would check their website for more info.
Hope that answers some of your questions.