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Springer Science + Business Media, Inc. Obesity Surgery, 17, 2007 631
Obesity Surgery, 17, 631-636
Background: The authors investigated body weight,
satiation, and gustative pleasure of obese patients 2years after a bariatric operation: the biliopancreatic
diversion with duodenal switch (DS).
Methods: 9 operated patients, 10 unoperated non-
obese and 10 unoperated obese persons participated
in the alliesthesia (food distaste) test.This test is a
psychometric assessment of satiation resulting from
the pleasure or displeasure following the repeated
ingestion of a sweet stimulus. Operated patients also
participated in the test before the DS operation.
Results: 2 years after DS, patients had lost 50% of
their body weight and their BMI was rendered similar
to that of the non-obese control group.Their satiation
was faster than in control and unoperated obesepatients. The responses of control and unoperated
obese patients were identical to those of pre-surgery
operated patients.
Conclusion: This indicates that at the time of the
experiment, patients actual body weight was higher
than their body weight set-point and that they would be
likely to continue to lose weight, at least beyond 2 years.
Key words: Morbid obesity, bariatric surgery, duodenal
switch, alliesthesia, taste, set-point
Introduction
Bariatric surgery has become increasingly popular
to cure morbid obesity. It is now widely accepted
that such surgery is the most effective treatment to
lose weight and improve obesity-related health
problems.1,2 Over 10,000 biliopancreatic diversionswith duodenal switch (DS) have been performed
over the last 15 years, and the popularity of this sur-
gery is still growing.3 This surgery4-6 combines
restrictive and malabsorptive effects and, after 2 to
10 years according to reports, removes about 75%
of excess weight.1,5,7,8
In a previous paper, Marceau et al9 reported that
satiation was accelerated in patients 3 and 6 months
after duodenal switch, while they lost weight and
moved from a mean BMI of 56.7 to 40.3 kg/m2. In
the alliesthesia test, developed by one of us,10-12patients ingest repeatedly a sweet stimulus and they
report quantitatively the pleasure that they felt after.
This test assesses initial pleasantness of the stimu-
lus, satiation time course, and negative alliesthesia,
i.e. the time it takes for a stimulus to pass from
pleasantness to unpleasantness. Marceau et al9 inter-
preted the accelerated satiation and alliesthesia that
they observed in their patients as resulting from a
lowered body weight set-point that explained the
patients rapid weight loss.
Based on experimental data, it has been proposedthat body weight is regulated at a set-point.10,13-19 In
a regulated system, any long-term change of the reg-
ulated variable mustbe mediated by a change in set-
point. In the case of body weight, any method to lose
weight must lower the body weight set-point if
weight loss is to be maintained over a long-term.
Otherwise, negative feedback would come into play
and counter any drop in body weight, and in this
case, the body weight would eventually return to its
Body Weight and Satiation after Duodenal Switch:
2 Years Later
Sebastien Paradis, PhD1; Michel Cabanac, MC1; Picard Marceau, MD,
PhD2; Patrick Frankham, PhD1
1Centre de recherche sur le mtabolisme nergtique (CREME), Anatomy and Physiology
Department, Laval University, Qubec, Canada; 2Centre de recherche de lHpital Laval (CRHL),
Chirurgie gnrale, Laval Hospital, Qubec, Canada
Correspondence to: Michel Cabanac, Anatomy and PhysiologyDepartment, Laval University, Qubec G1K 7P4, Canada. Fax:418-656-7898; e-mail: michel.cabanac@phs.ulaval.ca
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initial value. Thus, what should be explored in the
long-term is the influence of surgery on the set-point.
Clinical data show that there is an important and
continuous body weight loss during the first 2 years
after surgery, then a slight body weight regain of a
few kilograms, and eventually a more or less stableweight. Since the 2-years cap seems to present an
important shift in body weight change, we investi-
gated those patients presented previously9 and stud-
ied their body weight, satiation, and negative allies-
thesia at this particular interval after their operation.
Methods
Study Participants
Nine patients already studied, before, 3 and 6
months after biliopancreatic diversion with duode-
nal switch (DS) were studied again at 2 years after
surgery. Their mean BMI at the time of surgery was
56.7 4.2 kg/m2. Two years later, mean BMI was
28.4 1.4 kg/m2 with major improvement in their
general health status and healing of most co-mor-
bidities like sleep apnea and diabetes.
Ten non-obese, non-diabetic individuals were
recruited as control group. Smokers were excluded
because it had been shown that transient nicotine
can lower the set-point for body weight in humans,20
and in rats.21 The non-obese control group had a
mean BMI of 25.7 1.4 kg/m2.
Alliesthesia Test
Participants were instructed to arrive at the hospital
laboratory early in the morning, having fasted
overnight (e.g. skipped morning meal). All sessions
were conducted between 8:00 and 10:00 h.
Participants were tested individually under strict
confidentiality conditions. Body weight was record-ed before initiating the experimental session.
A sweet stimulus (common commercial caramel
candy: 6 g, 105 kJ total / 16.7 kJ from fat) was given
every 3 minutes to the participant. Fifteen seconds
after a stimulus was mouthed, the participant had to
indicate the pleasure experienced. This was done by
writing a mark on an analog 300-mm line. One end
of the line rated pleasantness, and the other end,
unpleasantness. The middle of the line rated indiffer-
ence. There was no numerical grading on the chart
except a middle mark for 0 (indifference). After
the patient wrote a mark on the scale, the distance
from zero was measured in millimeters and the mark
was removed by the experimenter after measure-
ment, in order to avoid influencing the next rating.Before the test, participants were instructed that they
could stop the test whenever they wanted to.
Measurements and Statistics
The BMI (kg/m2) of each participant was calculated.
The alliesthesia test measured pleasantness or
unpleasantness on a basis of 150 mm (e.g. each side
of 0). For each participant, we obtained three criti-
cal pieces of information: 1) initial rating was the
score given after the first stimulus; 2) time before neg-
ative rating was the time taken for the stimulus to pass
from pleasant to unpleasant, i.e. for the participants
rating to reach zero; and 3) satiation was the time at
which the participant wanted to stop the test.
Intergroup differences were compared by analyses of
variance (ANOVA) for repeated measures; paired post
hoc Students t-test was performed when necessary.
To compare dynamics of satiation of different groups,
we used the Kaplan-Meyer method for survival rate.
Ethics
The study protocol was approved by Laval
University Ethics Committee and Laval Hospital
Independent Ethics Committees (2001-141 A-1 R-
2). Each subject signed an informed consent before
study initiation. All sessions were conducted under
strict confidentiality conditions. Patients received
twenty dollars per visit as a compensation for their
participation in the study.
Results
BMI. The BMI (kg/m2) of operated patients contin-
ued to decrease 2 years after the DS operation, thus
confirming the results recorded 3 and 6 months after
surgery (Figure 1). After surgery, BMI fell from
56.7 4.2 to 46.5 4.0 (P
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patients had lost 50% of their body weight and their
BMI was rendered similar to that of the non-obesecontrol group, whereas weight remained stable over
the 6 months for the control obese group with a con-
stant BMI around 46 for the whole period (0, 3, and
6 months after surgery). Operated patients all
reported a better subjective quality of life and
expressed that they were satisfied with the results of
the surgery. They all reported that they were contin-
uing to lose weight without any significant effort.
Initial Rating. Operated patients gave a mean ini-
tial rating (pleasantness rating after the first stimu-lus) of 46.1 23.3 mm, compared to 78.8 15.7
mm before surgery, and 86.2 15.9 in non-obese
controls. This finding was not significantly lower 2
years after the surgery than before the surgery or
than in controls (Figure 2A; P=0.17).
Time before Negative Rating. Mean time before
negative rating 2 years after surgery was 8.1 1.4
min, which is lower than before surgery (16.0 3.9
min) or than in non-obese controls (24.9 5.5 min).
Thus, negative rating continued to appear faster in
operated patients 2 years after DS than in controls or
before the DS (Figure 2B; P=0.018).
Satiation. Two years after surgery, satiation timewas 12.7 2.2 min in operated patients, 26.7 5.0
min before surgery, and to 31.0 6.0 min in non-
obese controls. Therefore, satiation also continued
to appear faster in operated patients 2 years after the
surgery than in controls or before the surgery (figure
2C; P=0.014).
Two years after surgery, abandon rate was faster in
the group of operated patients than initially and in con-
trols (Figure 3). Thus, the results were identical as at 3
and 6 months after surgery. The longest session among
operated patients was 24 min, but was 84 min for the
non-obese controls and 81 min for obese controls.
In operated patients, the three measures of initial
rating, time before negative rating, and satiation
were similar to those obtained 3 and 6 months after
surgery. Non-obese and obese controls results were
similar to those of patients before the surgery for all
these three measures.
Discussion
Two years after surgery, the nine patients followed
in this present work had lost half of their weight.
That reaffirmed the efficacy of BPD-DS to reduce
body weight. Also, all patients considered that they
had made a good decision when they had applied for
surgery and they all declared that if they were in
their previous morbid state, they would make the
same decision again without hesitation.
Two years after surgery, patients negative rating
and satiation were still accelerated and all patients
reported that they were continuing to lose weightwithout special effort. This indicates that their actu-
al body weight remained somewhat higher than
their body weight set-point. If so, they are likely to
further lose weight. However, a non-significant
increase in the three measures related to taste and
satiation (initial rating, time before negative rating,
satiation time) further away from their surgery, with
decreasing body weight, might indicate a trend to a
return toward initial values similar to those of unop-
Satiation 2 Years after Duodenal Switch
Obesity Surgery, 17, 2007 633
0
10
20
30
40
50
60
70
Operated Obese controls Non-obesecontrols
Before surgery3 months after6 months after2 years after
a b c d
b b b
Figure 1. BMI of patients with a duodenal switch (n=9),
obese controls (n=10) and healthy controls (n=10). Two
years after the duodenal switch, the BMI of patients with
duodenal switch was half of the BMI before the surgery
and became similar to the BMI of healthy controls. Obese
controls without surgery maintained their high BMI.
Columns with different lowercase letters indicates signifi-
cant differences (P
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Paradis et al
634 Obesity Surgery, 17, 2007
0
20
40
60
80
100
120 Before surgery
3 months after
6 months after
2 years after
InitialRating
(mm)
A
0
5
10
15
20
25
30
35
* * *TimebeforeNegat
iveRating
B
0
5
10
15
20
25
30
35
40
Operated Obese controls Non-obese controls
* * *Satiation(min)
C
Group
Figure 2. (A) Initial rating, (B) negative alliesthesia, and (C) satiation of patients with a duodenal switch (n=9), obese con-
trols (n=10) and healthy controls (n=10). Two years after the surgery, results of DS patients remained similar to results at 3
and 6 months after the DS. Healthy controls results were also similar to those of obese controls. Columns with * indicatesignificant differences (P
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erated patients and control subjects. This may mean
that operated patients body weight was about to
match their set-point and that their body weight
would soon stabilize. This interpretation is consis-
tent with the long-term time-course after DS:
patients kept losing weight during the first 2 yearsafter surgery. Later, they tended to regain some of
the weight lost, and then they maintained a more or
less stable body weight.1,5
Obesity and body weight are the result of energy
balance, food intake, and energy expenditure. Food
intake is the result of experience of hunger, satiety,
and pleasure. It follows that these psychobiological
signals obey the regulatory set-point. The concept of
set-point does not prejudge the underlying cause of
obesity. The initial mechanism may be nervous or
endocrine. The fact that satiety and alliesthesia were
modified by surgery does not mean that resulting
weight loss is caused only by modulation of appetite
and satiation, nor that morbid obesity is caused by
excessive eating. Indeed, the causality may be
inverse. Morbid obesity is a complex disease that
excess food intake alone fails to explain.22 We used
these behavioral parameters (satiation, alliesthesia)
in order to investigate the patients regulatory func-
tion. A lowered set-point might also affect non-
behavioral mechanisms as well, such as an adjust-
ment of metabolism. Yet, modification of alliesthesia
is a measurable observation indicating a deep physi-ological change in whole body weight regulation.
Altogether, these results may contribute to the
debate about the causes of obesity. They tend to
show that morbid obesity is associated with a raised
body weight set-point but that the regulatory
processes are still working accurately at the new set-
point. Patients and obese controls alliesthesia
responses were normal and similar to those of non-
obese controls. Such a result also supports the con-
cept that the efficacy of a weight-loss method would
depend on the way that this method affects the set-point. The fact that BPD-DS lowers the set-point
may explain the long-term efficacy of this method.
When compared to the patients huge weight loss
and psychological comfort, these results show that a
set-point change is the best, and possibly only, way
to reduce body weight in the long term, whereas
dieting alone invariably leads to relapse.
It is of interest to note the consistency of results
obtained with the alliesthesia test. Results in operated
patients remained similar through the three sessions
over the 2 years after surgery. Furthermore, all allies-
thesia measures (initial rating, time before negative
rating, and satiation) were similar in the three obese
control tests and in non-obese controls. Such consis-
tency and reproducibility would validate the use ofthe alliesthesia test in clinics to explore the patients
ponderal state. The alliesthesia test should be a good
tool to assess the efficiency of different ways to lose
weight, whether the weight loss is achieved with sur-
gical, pharmacological,20 or dietary methods.
This work was supported by a grant from Natural Sciences
Engineering Research Council of Canada (NSERC). We thank
Suzy Laroche and Zo Lebel-Castonguay for their assistance in
study coordination.
References
1. Hess DS, Hess DW, Oakley, RS. The biliopancreatic
diversion with the duodenal switch: results beyond 10
years. Obes Surg 2005; 15: 408-16.
2. Livingston EH. Obesity and its surgical management.
Am J Surg 2002; 184: 103-13.
3. Rabkin RA. The duodenal switch as an increasing and
highly effective operation for morbid obesity. Obes
Surg 2004; 14: 861-5.
4. Marceau P, Biron S, Bourque R et al. Biliopancreaticdiversion with a new type of gastrectomy. Obes Surg
1993; 3: 29-35.
5. Marceau P, Hould FS, Simard S et al. Biliopancreatic
diversion with duodenal switch. World J Surg 1998;
22: 947-54.
6. Marceau P, Hould FS, Potvin M et al. Biliopancreatic
diversion (duodenal switch procedure). Eur J
Gastroenterol Hepatol 1999; 11: 99-103.
7. Nanni G, Balduzzi G, Botta C et al. Biliopancreatic
diversion. Clinical experience. Minerva Gastroenterol
Dietol 2005; 51: 209-12.
8. Gabriel SG, Karaindros CA, Papaioannou MA et al.
Biliopancreatic diversion with duodenal switch com-
bined with laparoscopic adjustable gastric banding.
Obes Surg 2005; 15: 517-22.
9. Marceau P, Cabanac M, Frankham PC et al.
Accelerated satiation after duodenal switch. Surg
Obes Relat Dis 2005; 1: 408-12.
10.Cabanac M. Physiological role of pleasure. Science
1971; 173: 1103-7.
11.Cabanac M, Pruvost M, Fantino M. Negative allies-
thesia for sweet stimuli after varying ingestions of
Satiation 2 Years after Duodenal Switch
Obesity Surgery, 17, 2007 635
8/14/2019 Body Weight and Satiation After Duodenal Switch 2 Years Later
6/6
glucose. Physiol Behav 1973; 11: 345-8.
12.Cabanac M. Sensory pleasure and alliesthesia. In:
Adelman G, Smith BH, eds. Elseviers Encyclopedia
of Neuroscience. Elsevier Science BV 1999:1836-37.
13.Hervey GR. The regulation of energy balance. Nature
1969; 223: 629-31.
14.Guy-Grand B, Sitt Y. Gustative alliesthesia: Evidence
supporting the ponderostat hypothesis for obesity. In:
Howard A, ed. Recent Advances in Obesity Research.
London: Newman 1975: 238-41.
15.Herberg LJ, Franklin KBJ, Stephens DN. The hypo-
thalamic set-point in experimental obesity. In:
Howard A, ed. Recent Advances in Obesity Research.
London: Newman 1975: 235-7.
16.Sclafani A, Springer D. Dietary obesity in adult rats:
similarities to hypothalamic and human obesity syn-
dromes. Physiol Behav 1976; 17: 461-71.
17.Keesey RE. The relation between energy expenditure
and the body weight set-point: its significance to obe-
sity. In: Burrows GD, Beumont PJV, Casper RC, eds.
Handbook of Eating Disorders. New York: Elsevier
1988:87-102.
18.Cabanac M, Richard D. The nature of the ponderostat:
Herveys hypothesis revived. Appetite 1996; 26: 45-54.
19.Cabanac M. Regulation and the ponderostat. Int J
Obes 2001; 25 (Suppl 5): S7-S12.
20.Cabanac M, Frankham P. Evidence that transient
nicotine lowers the body weight set-point. Physiol
Behav 2002; 76: 539-42.
21.Frankham P, Cabanac M. Nicotine lowers the body-
weight set-point in male rats. Appetite 2003; 41: 1-5.
22.Marceau P. Contribution of bariatric surgery to the
comprehension of morbid obesity. Obes Surg 2005;
15: 3-10.
(Received January 23, 2007; accepted March 19, 2007)
Paradis et al
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