It's the 1st 4 weeks of the LA Weight Loss Program. They really limit your choices so you can get used to the new way of eating and achieve maximum results.
I consider it detox
You get rid of all the processed crap in your body and learn what it feels like to eat real, healthy foods. It's pretty hardcore, but totally worth it. Personally, it gave me the stamina and motivation to keep going. Also, when you "graduate" to the Free to Live program it feels like heaven and you forget it's still a diet.