You can not say because someone went from 300# to 165# and walks that she is any healthier. In fact if she didnt do any weight training she lost lean tissue and now is weaker than when she started. Based on this logic, anorexic people are extremely healthy and we all know for a fact that isnt true.
I was going to write an article on why WW doesnt work but this article sums everything up. Minus one factor that I was going to add. (Yes a simple google search will bring this article up for you)
http://www.threecoaching.com/2010/12...ons-it-doesnt/
One additional thing I was going to add is the fact that humans hate keeping up with numbers. Eventually we grow bored and tired and fall off track.
Here is another good article.
http://articles.mercola.com/sites/ar...esnt-work.aspx