Here in Canada it may be different, cause the meals are just a well balanced meal for dinner. I personally find I was still starving though. A shake, or dinky little bar does NOT fill me up like a real meal does! Regardless of what is in it!
However, about 6 years ago I did it very briefly and lost about 6 lbs in 2 weeks. But to me it's not something I could handle long term... Have you tried WW? There's much more freedom there!!