I've heard that also. That is, 10 pounds for a size. However, if your exercising and building muscle it is less than 10 pounds. For example, I know someone that only lost a couple of pounds but went from a size 6 to a 4. I know, wish that was me!! Also, I noticed some people that responded lost more than 10 pounds but did not go down a size. Have you ever looked clothing sizes? I've noticed that a size is usually an inch until you get to size 12 than it increases. For example, a size 4 is a 25 in waist and 35 hip. A size 6 is 26 in waist and 36 hip. A size 8 is a 27 waist and 37 hip. However, it increases at size 12. (These measurements are only educated estimates). So it probably takes women to lose more weight to drop a size at size 12 and above unless gaining muscle mass because muscle weighs more but takes up less space. Hope I made sense. Angie