While Wikipedia is not always the best place to find information because of the nature of the site, where people can add or change information, it can be an ok place to find basic and general information. I basically used Wikipedia as a way to find the actual definition of bariatric surgery. While I have a lot of information on bariatric surgery I was unsure of the exact definition which is "Bariatric surgery, also known as weight loss surgery, refers to the various surgical procedures performed to treat obesity by modification of the gastrointestinal tract to reduce nutrient intake and/or absorption. The term does not include procedures for surgical removal of body fat such as liposuction or abdominoplasty." This definition will help the reader understand exactly what the surgeries that I'm talking about are.
The exact Wikipedia link is here