I have many friends who have lost weight on SW so it definitely works; that said, the fact that you can eat unlimited certain carbs and a lot of the food they recommend is chemical sugar laden, processed and generally poor quality, I would steer clear. My sister has just lost 5 stone doing Keto, and I have friends who have lost weight and got rid of medical problems using the Wahls Protocol. It seems these days that we now know that sugar is in all processed food and the high and constant levels are what is making us all insulin resistant/diabetic. The only way to burn the fat on your body is to stop putting sugar into your system, as that will always be used for fuel first. So by cutting out carbs and sugar, you will lose weight FAST. That said, it is very restrictive. Personally I favour fasting. I feel amazing the day after a fast and it has cured me of cravings and over eating.