I read the post at the very top of the FS forum stating the differences between FS and EFS. I only have the FS book not the EFS book, because until now I didn't know there were two :/ Personally, so far, I feel the FS is a perfect diet plan for me. However, I do want to tell everyone that I do see that quite a bit of people are posting about being dizzy and wanted to let everyone who didn't know that 800-1000 cal/day (avg. for EFS) is really very unhealthy for you! I hope no one is trying to do that long term because anything less than 1000 calories/day puts your body in starvation mode, which definetely doesn't help the metabolism. Also if you go from no exercies plan to the EFS exercise plan, be VERY careful. I watched someone pass out at my gym a few days ago, because she was sedentary and then started working out 5 days a week at the gym, and that was at Curves (a 30 min. work out!). I'm not dissing the EFS I'm just trying to make sure no one in here accidently hurts themselves. I start day one of FS tomorrow ..... yahhhhhh