Ali lost 100 pounds in one year. She did this with the help of a personal trainer. She is very tall at 6'1' and she now weighs 175 pounds. When she first met her trainer and weighed 278 pounds, he told her she wasn't eating enough! He asked her to eat six small meals a day and to make sure she got lots of protein in each meal. Now she is often eating chicken or fish at 10:00 in the morning. She says she no longer craves sugar.
When she first started losing weight she lost 20 pounds in the first month and that was very encouraging. See her weight loss story and picture here.
The Daily Beast site has a great slideshow and discussion about how 10 stars and celebritites went about losing weight. They include 
Lisa Key-Blair has lost 50 pounds in one year. She is featured in this months 
Actress and model Rebecca Romijn has lost nearly 60 pounds after giving birth to twins on December 28th last year. She says she lost the first 35 pounds within the first three weeks. (We must be counting the baby weight here too.) She says 
Marie Osmond, age 49, lost 45 pounds 2 years ago and has managed to keep it off. 
A high protein diet is increasingly being recommended for fast weight loss. A friend of mine needs a hernia operation and he was told he had to lose almost 25 pounds in less than three months before the operation. A hernia operation is much less risky if there is less stomach fat. He has been placed on a high protein, low carb diet. It's not recommended for the long term, but as a fast way to lose the extra weight.