It’s no secret that obesity is becoming more and more prevalent. The Centers for Disease Control and Prevention estimated that nearly 40 percent of American adults were obese, as of 2016. In response to this trend, more individuals are seeking surgical treatment for obesity. In fact, the American Society for Metabolic and Bariatric Surgery estimates that over a quarter-million Americans underwent bariatric surgery in 2017.
How Does Weight Loss Surgery Work?
Generally speaking, weight loss (aka bariatric) surgery results in weight loss for two reasons: restriction and/or malabsorption. Restriction refers to the physical shrinking of the stomach, limiting the amount of food that can be consumed at one time. Malabsorption works to decrease the utilization of nutrients by bypassing the areas where most nutrient absorption takes place. The gastric band, intragastric balloon, and sleeve gastrectomy rely on restriction to produce weight loss, while the gastric bypass and duodenal switch utilize restriction and malabsorption.
Types of Weight Loss Surgery
Laparoscopic Adjustable Gastric Band
The gastric band is one of the less invasive surgical options. The procedure involves the placement of an adjustable silicon band around the top portion of the stomach. Because the band is filled with saline, it can be tightened or loosened, depending on the individual’s need. (Think of wearing a belt to tighten or loosen your pants!) The band creates a smaller pseudo-stomach that helps the individual experience satiety with less food intake.
A relatively new procedure, the intragastric balloon involves the placement of an inflatable silicon balloon inside the stomach. The balloon is about the size of a grapefruit or softball. It promotes earlier satiety by restricting the amount of space inside the stomach. The balloon is typically removed after about six months and results in modest weight loss.
Also known as the gastric sleeve, this procedure is gaining in popularity by leaps and bounds. It now accounts for nearly 60 percent of the bariatric surgery procedures performed. In this procedure, the larger curvature of the stomach is removed, creating a small banana-sized tube with the remaining smaller curvature. Absorption of nutrients is not significantly affected, but rather the individual feels full with smaller amounts of food.
Roux-en-Y Gastric Bypass (RYGB)
Utilizing both restriction and malabsorption, the RYGB creates a small pouch from the top portion of the stomach and reroutes the intestines to connect the jejunum directly to the new pouch. The pouch is about the size of a walnut or an egg; this dramatically limits the amount of food that can be consumed at one time.
Likewise, food now bypasses the duodenum and a portion of the jejunum, which limits nutrient absorption. The remaining or “remnant” stomach is left inside the body, along with the bypassed portion of the small intestines, which allows for reversal of this procedure, if need be.
Biliopancreatic Diversion with Duodenal Switch (“Duodenal Switch” or BPD-DS)
The duodenal switch may be considered one of the most extensive bariatric surgery procedures, and it usually results in the most significant weight loss. The duodenal switch combines the gastric sleeve procedure with intestinal rerouting.
This procedure differs from the RYGB in two ways: 1) the pyloric sphincter is preserved, which helps to decrease dumping syndrome, and 2) about two-thirds of the intestines are bypassed. Sometimes a gastric sleeve is later converted to a duodenal switch, if weight loss or maintenance is not achieved.
Sara Glanz, MS, RD, LD, CNSC worked as a traveling dietitian for Dietitians On Demand for two years before joining the team as the corporate dietitian. In this role, she has championed the continuing education program to empower dietitians everywhere to achieve their professional goals.
If you have more questions about weight loss surgery, it’s always a great idea to speak with a registered dietitian. Registered dietitians are the only credentialed experts qualified to address your unique health questions. Email us at email@example.com to request a direct consultation with a dietitian today!
Adult obesity facts. Centers for Disease Control and Prevention website. https://www.cdc.gov/obesity/data/adult.html. Updated August 13, 2018. Accessed November 2, 2018.
Estimate of bariatric surgery numbers, 2011-2017. American Society for Metabolic and Bariatric Surgery website. https://asmbs.org/resources/estimate-of-bariatric-surgery-numbers. Updated June 2018. Accessed November 2, 2018.
Metabolic and bariatric surgery. American Society for Metabolic and Bariatric Surgery website. https://asmbs.org/resources/metabolic-and-bariatric-surgery. Updated November 2013. Accessed November 2, 2018.