Nutrition Management in Bariatric Surgery
Manual of Clinical Nutrition Management B- 18 Copyright © 2013 Compass Group, Inc.
Restrictive operations: Restrictive operations limit the amount of food that the stomach can hold by closing
off or removing parts of the stomach. These operations also delay the emptying of the stomach (gastric
pouch). Regurgitation is a common side effect of these procedures. The types of restrictive surgical
procedures include (1):
Laparoscopic adjustable gastric banding: A band made of special material is placed around the
stomach near its upper end, creating a small pouch and a narrow passage into the larger remainder of the
stomach. Necessary adjustments to the band are made during follow-up procedures (1). Laparoscopic
adjustable gastric banding has yielded greater success in achieving weight loss outcomes than vertical-
banded gastroplasty or adjustable silastic gastric banding (4).
Vertical-banded gastroplasty: Both a band and staples are used to create a small stomach pouch similar
to the pouch formed in laparoscopic adjustable gastric banding.
Adjustable silastic gastric banding: Approved in 2001 for use in the United States, this operation is
functionally similar to vertical-banded gastroplasty. This procedure makes a small pouch out of the
upper stomach. The pouch is stapled off from the rest of the stomach except for a small opening, which is
then reinforced with a ring made of Silastic, a soft and rubbery but strong material.
Sleeve gastrectomy or vertical sleeve gastrectomy: This is a newer procedure in which the stomach
capacity is restricted by stapling and dividing it vertically and removing more than 85% of the stomach.
This part of the procedure is not reversible. The stomach that remains is shaped like a very slim banana
and has a capacity of 1 to 5 oz (30 to 150 cc).
In addition to these procedures, another procedure performed less often is the silastic ring gastroplasty (1).
Laparoscopic adjustable gastric banding has largely replaced vertical banded gastroplasty (1). Restrictive
operations are the surgeries most commonly prescribed by bariatric surgeons (1).
Restrictive operations do not interfere with the normal digestive process (1). Rather, these procedures
restrict food intake through the creation of a small pouch at the top of the stomach where the food enters
from the esophagus. The pouch initially holds about 1 to 2 oz of food, but it expands to a 4- to 8-oz capacity
over a 6- to 9-month period. The pouch’s lower outlet has a diameter of approximately ¼ inch. The small
outlet delays the emptying of food from the pouch and causes a feeling of fullness. Although restrictive
operations lead to weight loss in almost all patients, some patients do regain weight (1). Six to 8 weeks after a
restrictive operation, the patient usually can eat ½ to 1 cup of food without discomfort or nausea. Food has to
be well chewed and consumed slowly. Most patients are unable to eat a large amount of food at one time, but
some individuals return to eating modest amounts of food without feeling hungry. A common risk of
restrictive operations is vomiting (1,4). This occurs when insufficiently chewed food particles overly stretch
the small stomach. Documented risks of vertical-banded gastroplasty include erosion of the band, breakdown
of the staple line, and, in a small number of cases, leakage of stomach contents into the abdomen. This leakage
requires an emergency operation. In less than 1% of cases, infection or death due to complications may occur
(3). Because of the low-energy content and small volume of food consumed following a restrictive procedure,
long-term multivitamin and mineral supplementation is required to meet the dietary reference intakes (DRIs)
for most nutrients (1).
Malabsorptive operations: Malabsorptive operations are also referred to as gastric bypass operations. In
these procedures, a surgeon makes a direct connection from the stomach to a lower segment of the small
intestine, bypassing the gastric fundus, body, antrum, duodenum, and a variable length of proximal jejunum.
Because gastric bypass operations cause both malabsorption and restricted food intake, these operations
produce more weight loss than restrictive operations. Patients who have bypass operations generally lose
two thirds of their excess weight within 2 years (2,3). The risks of pouch stretching, band erosion, breakdown
of staple lines, and leakage of stomach contents into the abdomen are about the same as the risks in vertical-
banded gastroplasty (3). Types of malabsorptive or gastric bypass operations include (1):
Roux-en-Y gastric bypass: This operation is the most common gastric bypass procedure (1). First, to
restrict food intake, a small stomach pouch is created by stapling or vertical banding. Next, a Y-shaped
section of the small intestine is attached to the pouch to allow food to bypass the duodenum (the first
segment of the small intestine) and the first portion of the jejunum (the second segment of the small
intestine). This step of the procedure causes reduced absorption of energy and critical nutrients (1).
Biliopancreatic diversion and biliopancreatic diversion with duodenal switch: In the
biliopancreatic diversion operation, portions of the stomach are removed. The small pouch that remains