By my count about 1/4 of the contestants have had weight loss surgery--it will be interesting to see how well they do/what special problems they have compared to the others.
The surgical ones are (I think...I count 5 out of 21 contestants, which seems like an odd #, so I may be missing someone):
Rick--gastric bypass
Jessica--lap band
Montina--lap band
Burgandy--lap band
Allie--vertical banded gastroplasty
