I too used to do 1000 calories a day, and you can lose weight, and pretty quickly that way. But, and its a big but, you are way more likely to pile it all back on quickly than you would if you ate the SW way.
SW is great because you dont have to ever feel like you are on a diet. You dont feel deprived, you dont feel starved and you dont feel like you are missing out on anything. And you DO lose weight. These guys have been around for 40 years, developing their eating plans, and making sure it works. If it didnt, they would have gone bust years ago.
When I first started SW a few weeks ago, I was truly amazed at how much you could eat. It seemed ludicrous that you could stuff your face so much and still lose. But you do. You just have to get rid of all your preconceptions and trust in the plan, because it really IS effective.