An Overview of Bariatric Surgery
Kristin Dermody
Angela Illing
May 23, 2005
THE OBESITY
EPIDEMIC
A Quick Background of Obesity
 Derived from the Latin word obesus – “to
devour”
 Definition: having a very high amount of
body fat in relation to lean body mass
 Classifications using Body Mass Index
(BMI)
BMI Categories

A BMI of:
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<18.5
18.5-24.9
25-29.9
30-34.9
35-39.9
40-49.9
50 and above
Classifies one as:
Underweight
Normal weight
Overweight
Obesity Class I
Obesity Class II
Obesity Class III
Super Obesity
Obesity is a BIG problem…


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1.7 billion worldwide
are overweight or
obese
The US has a higher
percentage of
overweight and obese
people than any
country in the world
And the numbers are
growing…
US Incidence of Obesity


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Approximately 2/3 of the United States
population is overweight.
Of those, almost 50% are obese.
In total, approximately 5% of the US
population is morbidly obese
Alarmingly, the BMI subgroups growing
the most quickly are 35 or higher and 40 or
higher.
Massachusetts: Not-so-’Phat’ Facts

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55% of Mass adults  overweight or obese*
Of these obese adults**
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18% non-Hispanic white
30% non-Hispanic black
22% Hispanic
24% of Mass high school students  overweight or at
risk of becoming overweight

Obesity rate among Mass adults
by 81% from 1990 to 2000*
*CDC BRFSS, 2002; **CDC YRBSS, 2003
History of Obesity
Obesity Trends* Among U.S. Adults
BRFSS, 1985
(*BMI ? 30, or ~ 30 lbs overweight for 5’ 4” person)
1985
No Data
<10%
10%–14%
Source: Behavioral Risk Factor Surveillance System, CDC.
Obesity Trends* Among U.S. Adults
BRFSS, 1991, 1996, 2003
(*BMI 30, or about 30 lbs overweight for 5’4” person)
1991
1996
2003
No Data
<10%
10%–14%
15%–19%
Source: Behavioral Risk Factor Surveillance System, CDC.
20%–24%
? 25%
Potential Consequences of Obesity

Obesity is associated with a rise in many
comorbid conditions, including:
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Type 2 Diabetes
Hyperlipidemia
Hypertension
Obstructive Sleep Apnea
Heart Disease
Stroke
Asthma
Back and lower extremity weightbearing degenerative problems
Cancer
Depression
AND MORE!
CVD & Obesity


Fact: Obesity contributes to these co-morbid
conditions, however…
Recent JAMA article by Gregg et al* suggests
CVD risk factors across all BMI groups over
past 40 years

Suggest: Overweight not quite as bad as it once was,
considering other factors:


Risk r/t awareness, aggressive identification,
pharmacological tx of high chol, HTN.
Note: Obese persons still have risk factor levels
vs..lean persons.
Gregg EW, et al. Secular Trends in Cardiovascular Disease Risk Factors According to Body Mass Index in US
Adults. JAMA, 2005:293:1863-1874
Impact of Obesity

These comorbid conditions are together
responsible for more than 2.5 million
deaths per year worldwide*.

This is in addition to billions of dollars in
healthcare costs and lost productivity.
*World Health Organization, World Health Report 2002
Obesity and Life Expectancy

Recent NEJM article* – If current rates of obesity are
left unchecked, the current generation of American
children will be the first in two centuries to have a
shorter life expectancy than their parents.

The life-shortening impact of obesity (currently
estimated at 1/3 to ¾ year) could rise to 2 to 5 years,
or more, as obese children spend more years at risk
for comorbid conditions.
Olshansky SJ, et al. A Potential Decline in Life Expectancy in the United States in the 21 st Century.
NEJM, 352(11):1138-1145, 2005
Obesity and Life Expectancy

The morbidly obese are perhaps the worst
off…
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Compared to a normal-weight person, a 25year-old morbidly obese man has a 22%
reduction in expected remaining lifespan.
This is an approximate loss of 12 YEARS!
This number will also likely grow if the everexpanding numbers of currently obese
children continue as obese adults…
TREATING
OBESITY
Weight Loss Strategies
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Diet therapy
Increased Physical Activity
Pharmacotherapy (e.g., Orlistat, Meridia)
Behavioral Therapy
Hypnosis
Any combination of the above
Bariatric Surgery
An effective treatment for combating obesity
Bariatric Surgery

1991: NIH establishes
guidelines for the surgical
therapy of morbid obesity

Recommends BMI criteria
BMI > 40
 BMI > 35 + significant
comorbidities

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This therapy now referred to
as Bariatric Surgery
Types of Bariatric Surgery

Purely Restrictive
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Restrictive > Malabsorptive
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Short-limb/Roux-en-Y gastric bypass (BWH)
Long-limb/distal Roux-en-Y gastric bypass
Malabsorptive > Restrictive
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Gastric Balloons (not approved for use in USA)
Vertical-banded gastroplasty
Gastric adjustable banding (BWH)
Biliopancreatic diversion (BPD)
BPD with duodenal switch
Very long limb Roux-en-Y gastric bypass
Purely Malabsorptive
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Jejunoilieal bypass
Jejunocolonic bypass
A Brief History of Bariatric Surgery

First developed:
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Pts with short bowel syndrome  weight loss
First weight loss surgeries (ca. 1950s)
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Intestinal bypass
 Low-risk
surgically BUT many patients
developed serious and often fatal
complications

Biliopancreatic diversion
 Effective
BUT with high risk and many
complications
Evolution of the Roux-en-Y

Gastric partitioning (Roux-en-Y GBP)
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Based on observations of weight loss in pts
receiving subtotal gastric resections for other
conditions
1967 – First performed
Continues to be studied and refined
Roux-en-Y
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Open*
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2 hour procedure
3 days in-house
4 weeks – Return to work
60-70% EBW loss @ 2 yrs
0.5-1.0% Risk of Death
Dumping Syndrome
Laparoscopic*
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2-4 hour procedure
3 days in-house
2-3 weeks – Return to work
60-70% EBW loss @ 2yrs
0.5-1.0% Risk of Death
Dumping Syndrome
* Data based on averages.
Evolution of Gastric Banding

1970s
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1980s
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Alternative to Roux-en-Y in Europe &
Scandinavia
Adjustable silicone band developed
1990s
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Laproscopic techniques for placement
developed
Gastric Banding

Adjustable Lap Band
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1 hr procedure
1 day in-house
1 wk – Return to
work
40-45% EBW loss
@ 2 yrs
<0.1% Risk of Death
Self-sabotage easier
Who Gets Bariatric Surgery?

Gender
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Age
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19% Males
72.6% Females
(8% gender not reported)
Mean age 39 years
Range 16-64 years
BMI
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Mean BMI 46.9
Range 32.3-68.8
Buchwald H, et al. Bariatric Surgery: A Systematic Review and Meta-analysis. JAMA, 14:1724-37, 2004
Medical Nutrition Therapy
and
The Post-op Bariatric Patient
Post-Surgical Nutrition
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Balanced/healthy diet
Liquids to pureed to soft to solid*
High nutrient density, quality
Modified in lactose, fat, sugar
Adequate fluid
Portion Control
Meal Periods/Eating time
MVI/MIN
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Ca (>1200mg/d) + D (10-20mg)
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Folate (800-1000mcg) +B12
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Iron (45-100mg elemental – premenstrual)
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Vitamin C (75-100mg)
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Thiamin
Self-monitoring
Eating triggers/behaviors
Exercise
* Time line may vary among institutions
Post-Op Roux-En-Y Diet
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Stage One (1 day)
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Water and clear liquids
Non-caloric, noncarbonated, noncaffeinated liquids
Fluid goal: 28-32oz/d
Stage Two (14 days)
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High protein, low
sugar beverages
Fluid goal: 56oz
Protein goal: 60-70g/d
Chewable MVI + Ca
Post-Op Roux-En-Y Diet
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Stage Three (4 weeks)
 5 – 2oz servings diced
protein
 Fluid goal: 56oz
 Protein goal: 60-70g
 Chewable MVI + Ca
Stage Four (4 months)
 3 meals, 2 snacks
 850kcal/d
 Fluid goal: 56oz
 Protein goal: 60-70g
 Chewable MVI + Ca
Stage
Five (ongoing)
Regular Meals
1200-1500kcal
Fluid & Protein goals:
same as above
Post-op Lap Band Diet
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Stage One (1 day)
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Water & Clear Liquids
Non-carbonated, non-caffeinated, non-caloric liquids
Fluid goal: 28-32oz/d
Stage Two (14 days)
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5-8oz servings of High Protein, low sugar Beverage
Fluid goal: 56oz
Protein goal: 50-60g
Chewable MVI + Ca
Post-op Lap Band Diet
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Stage Three (14 days)
 Pureed Foods, Semi solids
 2 small meals, 3 snacks
 Fluid goal: 56oz
 Protein goal: 50-60g
 Chewable MVI + Ca
Stage Four (ongoing)
 Regular meals: 3 meals,2 snacks (1000-1200)
 Fluid goal: 56oz
 Protein goal: 50-60g
 Chewable MVI + Ca
Post-Surgical Nutrition
& Exercise
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RD seen frequently
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1m 3m 6m 1yr
Exercise
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No heavy lifting or exercise 6-8wks post-op
Walking daily OK, encouraged
After cleared, strength training important to
help skin stretch back
Helps with weight loss in the long run
When Surgery and
Follow-Up Go Well…
Efficacy of Bariatric Surgery for
Weight Loss

Mean percentage excess weight loss:
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61.2% - All Patients
47.5% - Gastric Banding
61.6% - Gastric Bypass
68.2% - Gastroplasty
70.1% - BPD or duodenal switch
*Buchwald H, et al. Bariatric Surgery: A Systematic Review and
Meta-analysis. JAMA, 14:1724-37, 2004
Roux-en-Y: Metabolic Sequelae
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
Human body regulates nutrient intake over time
by secreting hormones
Over 40 hormones play a role in regulation of
feeding.
Roux-en-Y: Metabolic Sequelae

Two types:

Satiety hormones
 Short-term
 Help regulate meal size; daily intake
 Secretion decreases meal size; reduces time to stop
 Includes (among others) cholecystokinin, amylin, glucagonlike-peptide 1 (GLP-1), enterostatin, and bombesin

Adiposity hormones
 Long-term
 Related to energy stores
 Secretion delays onset of beginning of meal
 Includes insulin, leptin
Roux-en-Y: Metabolic Sequelae
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Also of note is ghrelin, the
endogenous ligand for the growth
hormone secretagogue receptor
Mostly secreted in the fundus of the
stomach (part bypassed in RYGB)
Contrary to satiety hormones, ghrelin
is orexigenic – i.e., increases appetite
(fasting increases levels)
Roux-en-Y: Metabolic Sequelae
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Plasma ghrelin normally increases after
non-surgical weight loss
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This supports long-term weight homeostasis
Proportional to lean body mass
Initial report showed circulating plasma
ghrelin greatly decreased in pts s/p RYGB
Past theory: exclusion of the fundus of the
stomach responsible for lower ghrelin
levels (and therefore greater weight loss)
Roux-en-Y: Metabolic Sequelae
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Studies since then have shown no change
or increase in ghrelin after bypass
Additionally, found that post-pyloric
nutrient stimulation vs.. stomach distention
responsible for changes in ghrelin levels
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Does not support idea that bypassing stomach
fundus responsible for changes, if any, in
ghrelin levels
Overall, still not well understood
Strader AD, et al. Gastrointestinal Hormones and Food Intake.
Gastroenterology, 128:175-91, 2005
Roux-en-Y: Metabolic Sequelae

Further investigation is needed, but thought that
one reason certain types (i.e., RYGB) of bariatric
surgery are successful at reducing food intake and
causing weight loss may be related to enhanced
secretion of satiety signals (ghrelin or others).
Effect on Comorbid Conditions
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Diabetes
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Hyperlipidemia
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70% - Improved
HTN
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76.8% - Completely resolved
86.0% - Resolved or improved
61.7% - Resolved
85.7% - Resolved or improved
Obstructive Sleep Apnea
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83.6% - Resolved
85.7% - Resolved or improved
Buchwald H, et al. Bariatric Surgery:
A Systematic Review and Metaanalysis. JAMA, 14:1724-37, 2004
Metabolic Changes and Diabetes

Many metabolic changes contribute to improvement
and/or resolution of DM s/p bariatric surgery:
 Recovery of acute insulin response
 Decreases of inflammatory indicators (C-reactive
protein and interleukin 6)
 Improvement in insulin sensitivity correlated
w/increases in plasma adiponectin
 Changes in the enteroglucagon response to glucose
 Reduction in ghrelin levels (s/p RYGB, but not
banding)
 Improvement in beta cell function (s/p banding, but
not RYGP)
Effect on Quality of Life
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Studies show overall QOL greatly improved
 Relief from comorbidities
 Improved appearance
 Perception of improved:
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Well-being
Social function
Body self-image
Self confidence
Ability to interact with others
Increased time spent in recreational and physical activities
Enhanced productivity
Increased economic opportunities
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Often new employment
More lucrative employment
PROBLEMS AND
COMPLICATIONS
of Bariatric Surgery
Possible Complications of Bariatric
Surgery
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General Complications
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Pulmonary embolism
Incisional hernia
Gallstone formation
Major wound infection and seroma
Abdominal fluid collection
Subphrenic abscess
Peritonitis
Procedure-Specific
Complications (RYGB)
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Anastomotic or staple-line leak
Acute gastric distention
Staple-line disruption
Stomal stenosis
Stomal ulceration
Small-bowel obstruction
Occlusion of Roux limb
Intermediate Complications
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Wound Infection
Intra-abdominal bleed
Gastric remnant necrosis
Ischemic Roux-limb
Internal hernia
Long-Term GI Complications
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Nausea
Constipation
Abdominal pain
Marginal ulcers
Incisional hernias
Vomiting
Diarrhea
Gallstones
Gastritis
Intestinal Obstructions
Incidence of Complications

Operative mortality (< 30 days):
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0.1% for Purely Restrictive Procedures
0.5% for Gastric Bypass
1.1% for BPD or Duodenal Switch
Long-Term Nutrition Complications
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Malnutrition
Vitamin and mineral deficiencies
Weight loss failure
Dehydration
Anemia
Dumping Syndrome
Hair loss
Dry skin
Risk of Vitamin and Mineral Deficiencies
Post-op

Calcium and Vitamin D
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Iron
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Absorption decreased d/t decreased contact of food with gastric
acid; reduced conversion of iron from ferrous to ferric form
(MVI)
Vitamin B12
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Reduced absorption d/t bypassed duodenum, proximal jejunum
(R-en-Y)
Life-long supplements mandatory
Absorption decreased d/t decreased contact with intrinsic factor
60% of patients require long term supplementation of B12
Thiamine
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Connection to Wernicke’s syndrome
Cases not well documented
Post-Surgical Eating Avoidance
Disorder (PSEAD)
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De novo synthesis of eating disorders postGBP
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Do not fit criteria for AN, BN, or BED

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No history pre-operatively
Classify now as EDNOS
Characteristics consistent enough to
suggest new eating disorder
Post-Surgical Eating Avoidance
Disorder (PSEAD)
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Proposed Criteria:
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Previous h/o morbid obesity followed by
bariatric surgery over the last 2 years
Higher speed of weight loss than the average
Use of purgative strategies or excessive
reduction of food intake, related or not
related to binge eating episodes
Post-Surgical Eating Avoidance
Disorder (PSEAD)
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Proposed Criteria:
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Reaction of extreme anxiety +/or negative
attitude when nutritional correction introduced
Intense fear of going back to pre-op wt
Does not accept attempts to interrupt the wt loss
Denies doing something exaggerated that
account for loss
Perceives a positive return with wt loss in spite
of evidence to the contrary
Post-Surgical Eating Avoidance
Disorder (PSEAD)
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Proposed Criteria:
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Body image dissatisfaction or distortion
Follow-up nutritional tests (such as laboratory tests)
alterations that are significant and/or not in line with
the surgical technique, maintained for more than 2
months after initial interventions
Exclude AN and BN, according to DSM IV
Exclude Simple Phobias (I.e., Food or Choking
Phobia) according to DSM IV
Exclude organic causes as the most probable factor
for excessive weight loss
Segal et al. Post-Surgical Refusal to Eat: Anorexia Nervosa, Bulimia Nervosa or a New Eating Disorder? A Case
Series. Obes Surg, 14:353-359, 2004
Post-Surgical Eating Avoidance
Disorder (PSEAD)
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A proposed ED classification
Not yet part of the DSM IV
ED: Contraindication for GBP?

Pt with h/o of AN or BN likely not a good
surgical candidate
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Pt at high risk for malnutrition after surgery
Some with h/o ED receive surgery
Important to screen carefully before AND
monitor closely post-op to prevent relapse
of disorder, malnutrition.
Long Term Impact
&
Future Directions
Long-Term Changes: Weight Regain

One study of 342 gastric bypass pts showed
excellent long-term weight maintenance:
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% weight loss at:
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1 year (89%)
2 years (87%)
5 years (70%)
10 years (75%)
However, potential for pouch stretch, selfsabotage, etc. leading to weight regain over time.
Surgery relatively new, will have to wait and
reanalyze data in a few years.
“Long-term changes in energy
expenditure and body composition
after massive weight loss induced by
gastric bypass surgery”
Das SK, et al. Am J Clin Nutr. 2003;78:22-30.
Study: EE & Body Composition

Objective:

To determine changes in energy expenditure
and body composition with weight loss after
gastric bypass surgery; to identify pre-surgery
indicators of weight loss.
Study: EE & Body Composition

Design & Methods:

Included 30 obese men and women
Average age 39.0 + 9.6 y
 Average BMI (kg/m2) 50.1 + 9.3
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Tested longitudinally under weight-stable
conditions before surgery and after weight
loss and stabilization (14 + 2 mo)
Measured total energy expenditure (TEE),
resting energy expenditure (REE), body
composition, and fasting leptin
Study: EE & Body Composition

Results:
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Weight loss 53.2 + 22.2 kg body weight
Significant reduction in REE (-2.4 + 1.0 MJ/d; P <
0.001) and TEE (-3.6 + 2.5 MJ/d; P < 0.001).
Changes in REE predicted by changes in fat-free
mass and fat mass
Average physical activity level (TEE/REE) was 1.61
at both baseline and follow-up (P = 0.98)
Weight loss predicted by baseline fat mass and BMI
but not by any energy expenditure variable or leptin.
Measured REE at follow-up was not significantly
different from predicted REE.
Study: EE & Body Composition

Conclusions:
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TEE and REE decreased by 25% on average
after massive weight loss and weight
stabilization after gastric bypass
Decreases in REE largely or completely
predicted by decreases in body FFM and fat
mass
Fasting leptin at baseline found not to be a
predictor of energy efficiency/changes, as
some previous studies had shown
Study: EE & Body Composition

Conclusions:

Suggested further studies to examine other
explanations for variability in weight loss
between patients after gastric bypass surgery


? Psychological, behavioral factors
Suggested permanent reduction in energy
intake critical for long-term weight
management
Other Future Weight Loss Strategies


Gastric stimulation – idea of placing a
pacemaker-like device in stomach to control
contractions; release of hunger/satiety hormones
Hormone therapy - “exendin-4”

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Hormone produced in Gila monster salivary gland
Similar to GLP-1 in humans

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Reduces gastric emptying
Lowers fasting plasma glucose
Reduces food intake
May prove effective therapy for DM, obesity
OTHER CONCERNS
Nutrition Support in the Critically Ill GBP Patient

Enteral feeding possible, if warranted:


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Tube surgically placed in excluded stomach
(RYGBP)
Nasoenteric tube placed endoscopically
through pouch
If neither option possible (e.g. if pt has
anastomotic leak) TPN.
Bariatric Surgery in Special
Populations
Adolescents
Elderly (over 60)
Adolescents

Few medical centers currently performing
bariatric surgery on this population


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Only extreme cases
Highly controversial given incomplete
growth period
Specialized medical team only
Elderly


Advanced age common contraindication to
surgery
Research suggests age may not be as
indicative of outcome as once believed

Successful GBP cases in 60+*
St.Peter, Shawn. Impact of Advanced Age on Weight Loss and Health Benefits
After Laparoscopic Gastric Bypass. Arch Surg; 140:165-168;2005
Spouses of GBP Patients

Study by Madan AK, et al (2005) showed
gastric bypass patient’s spouses who are
obese are more likely to have weight gain
while the patients lose weight after surgery

Suggest pre-operative counseling for spouses
or even consider them for surgery as well
Summary


Bariatric surgery is a seemingly effective therapy
for morbid obesity that is gaining in popularity
and prevalence
Bariatric surgery provides significant

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Loss of excess body weight
Relief from comorbidities:

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DM, HTN, hyperlipidemia
Improvement in QOL for patients
However, these surgeries put pts at risk for

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Post-op complications & mortality
Nutritional deficiencies & GI complications
Psychosocial complications
References
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Kim JJ, et al. Surgical Treatment for Extreme Obesity: Evolution of a
Rapidly Growing Field. Nutr Clin Prac 18:109-23, 2003
Buchwald H, et al. Bariatric Surgery: A Systematic Review and
Meta-analysis. JAMA, 14:1724-37, 2004
Olshansky SJ, et al. A Potential Decline in Life Expectancy in the
United States in the 21st Century. NEJM, 352(11):1138-1145, 2005
Merkle EM, et al. Roux-en-Y Gastric Bypass for Clinically Severe
Obesity: Normal Appearance and Spectrum of Complications at
Imaging. Radiology, 234(3):674-83, 2005
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