Calories are like money in a bank. Burn more than you eat, and you will lose weight. One pound equals 3500 calories. Do not eat fewer than about 1200-1400 calories a day, because fewer than that is dangerous for your health. Do daily exercise that you enjoy that gets your heart rate up over 100 beats per minute for at least a half hour. Get yourself in GOOD HEALTH, then don't worry about what you look like if you are healthy!

I lost about 20 lbs in 4 weeks on the South Beach diet along with working out 20 minutes a day (jogging)

Pilates is great. I just started a couple weeks ago and I feel great. Get a mat and a DVD and you will be on your way. You really feel the burn with pilates! Good luck!