The normal standard is 100 pounds or more over your ideal weight. A bmi of 40 or above. Or a lower bmi, with obesity related health issues, diabetes, sleep apnea, hypertension, gerd, reflux and I'm sure there are more.
WLS is not a first line defense in the battle of obesity.......it's the "I've tried and tried everything else" now I need something more.
What type of surgery are you thinking about/researching? A really, really good web site with mounds of info is www.obesityhelp.com
If you can think of a question it has probably been ask before and is in the archieves of this site.
Jiff is great when it comes to info, I'm sure she will be along soon.
Keep asking questions.