Please read the clip first and then my notes - it'll make more sense. Thanks.

Ok, here's the deal. The way the study was set up, if someone had lost a significant amount of weight at any point in their life and was still at least 10% lighter than they had been at their heaviest, they'd qualify for the survey. For example, a 300 lb woman who had dieted down to 150 at some point would qualify as long as she weighed no more than 270 at the start of the study (10% of 300 is 30, so 270 would be 10% lighter than her highest weight). At the end of the 1 year study, anyone who had gained no more than 5% of their total weight at the start of the study was considered successful.

Think about this - 5% of her weight of 270 at the start of the study would be 13.5 lbs. This means that at the end of the study she could weigh as much as 283.5 lbs and STILL be considered as having "successfully maintained her weight loss."

There's a lot more at her blog - it's well worth a look