preoperative eating behavior, postoperative dietary adherence, and weight loss after gastric bypass...
TRANSCRIPT
A
K
aK
CS
1d
Allied health article
Preoperative eating behavior, postoperative dietary adherence, andweight loss after gastric bypass surgery
David B. Sarwer, Ph.D.a,b,c,*, Thomas A. Wadden, Ph.D.a, Reneé H. Moore, Ph.D.d,Alexander W. Baker, B.A.a, Lauren M. Gibbons, B.A.e, Steven E. Raper, M.D.f,
Noel N. Williams, M.D.faDepartment of Psychiatry, Center for Weight and Eating Disorders, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
bDepartment of Surgery, Division of Plastic Surgery, University of Pennsylvania School of Medicine, Philadelphia, PennsylvaniacEdwin and Fannie Gray Hall Center for Human Appearance, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
dDepartment of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, PennsylvaniaeDepartment of Clinical and Health Psychology, University of Florida, Gainesville, Florida
fDepartment of Surgery, Hospital of the University of Pennsylvania, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
Received August 13, 2007; revised March 13, 2008; accepted April 13, 2008
bstract Background: To investigate the relationship between preoperative eating behavior, postoperativedietary adherence and weight loss after gastric bypass surgery in a major, urban medical center witha comprehensive bariatric surgery program. Despite the significant weight loss and dramaticimprovements in co-morbidities associated with bariatric surgery, a significant minority of patientsappear to experience suboptimal weight loss. The reasons for this are not well understood, but thesuboptimal weight loss is often attributed to preoperative psychosocial characteristics and/or eatingbehaviors, as well as poor adherence to the recommended postoperative diet.Methods: A prospective investigation was performed of 200 female and male patients who werestudied both preoperatively and 20, 40, 66, and 92 weeks postoperatively. All patients underwenteither open or laparoscopic Roux-en-Y gastric bypass surgery. The measures were the percentage ofweight loss, macronutrient intake, dietary adherence, and eating behavior.Results: Gender, baseline cognitive restraint, and self-reported adherence to the postoperative dietat postoperative week 20 were associated with the percentage of weight loss at postoperative week92. Those high in dietary adherence had lost 4.5% more weight at postoperative week 92 than thoselow in dietary adherence.Conclusion: Baseline cognitive restraint and adherence to the recommended postoperative dietwere associated with the percentage of weight loss after gastric bypass surgery. These resultssuggest the potential utility of pre- and/or postoperative dietary counseling interventions to improvethe postoperative outcomes. (Surg Obes Relat Dis 2008;4:640–646.) © 2008 American Society forMetabolic and Bariatric Surgery. All rights reserved.
Surgery for Obesity and Related Diseases 4 (2008) 640–646
eywords: Bariatric surgery; Gastric bypass surgery; Cognitive restraint; Dietary adherence
dp1bb[
Supported, in part, by the National Institute of Diabetes and Digestivend Kidney Diseases (grant K23-DK60023 to D. B. Sarwer and grant24-DK065018 to T. A. Wadden).
*Reprint requests: David B. Sarwer, Ph.D., Department of Psychiatry,enter for Weight and Eating Disorders, University of Pennsylvaniachool of Medicine, 3535 Market Street, Philadelphia, PA 19104.
3E-mail: [email protected]
550-7289/08/$ – see front matter © 2008 American Society for Metabolic and Boi:10.1016/j.soard.2008.04.013
Bariatric surgery has surged in popularity during the pastecade. Although approximately 13,000 procedures wereerformed in the United States in 1998, an estimated03,000 were completed in 2003 [1]. The most commonariatric procedure in the United States is Roux-en-Y gastricypass, which accounted for 88% of all procedures in 20021]. At 2 years postoperatively, patients have typically lost
5% of their initial body weight with the bypass procedureariatric Surgery. All rights reserved.
awtc
tRaagii
uoephpi[bs
ltctb1ahlger
rpmscat
M
P
wtJop
M
ct
Wmho
tw4pf
641D. B. Sarwer et al. / Surgery for Obesity and Related Diseases 4 (2008) 640–646
nd 25% with restrictive banding procedures [2]. Theseeight losses are significantly larger and more durable than
he weight losses typically achieved with behavior modifi-ation or pharmacotherapy [3].
Despite these impressive weight losses, significant pa-ient-to-patient variability exists in postoperative outcomes.eviews have concluded that 10–20% of patients do notchieve these weight losses or else experience prematurend/or sizable weight regain [4–7]. For example, 9% ofastric bypass patients and 25% of adjustable gastric band-ng patients had failed to maintain at least a 5% reduction innitial weight at 10 years postoperatively [8].
The reasons for these suboptimal outcomes are not wellnderstood. Some investigators have suggested that the pre-perative psychosocial status is associated with the postop-rative outcome [4–7]. The evidence supporting this hy-othesis is inconclusive, with many studies of this issueaving methodologic problems. The relationship betweenreoperative eating behavior and postoperative weight losss similarly unclear. Several studies [9–13], but not all14,15], have suggested that the presence of preoperativeinge eating or excessive sweet eating is associated withuboptimal postoperative weight loss.
Adherence to the rigorous postoperative diet also is be-ieved to contribute to postoperative outcomes. Caloric in-ake often increases significantly during the postoperativeourse [8,14–19]. In the Swedish Obese Subjects trial [8],he surgical patients consumed approximately 2900 kcal/defore surgery. Their intake had decreased to approximately500 kcal/d 6 months after surgery, but it had increased topproximately 2000 kcal/d 10 years later, when the patientsad regained approximately 10% of their maximal weightoss. Thus, despite the impressive strength of bariatric sur-ery as a treatment for extreme obesity, the psychosocial,ating behavior, and dietary variables can play an influentialole in the postoperative outcome.
The primary aim of this study was to investigate theelationship of the 92-week postoperative weight loss to thereoperative psychosocial variables (i.e., self-esteem andood), preoperative eating behaviors (i.e., cognitive re-
traint, disinhibition, and hunger), dietary intake (i.e., dailyaloric intake and percentage of calories from fat, protein,nd carbohydrates), and patients’ self-reported adherence tohe postoperative diet.
ethods
articipants
The study participants were 200 individuals who under-ent Roux-en-Y gastric bypass surgery at the Hospital of
he University of Pennsylvania from November 2001 toune 2004. The institutional review board of the Universityf Pennsylvania approved the study, and all participants
rovided informed consent before entering the study.easures
Approximately 4 weeks before surgery, the participantsompleted a psychosocial/behavioral evaluation to assessheir appropriateness for surgery [20].
As a part of this assessment, patients completed theeight and Lifestyle Inventory [21], which provides infor-ation on race, employment, education, and self-reported
eight. Weight was confirmed with a digital scale at thenset of the evaluation.
After completing the psychosocial/behavioral evaluation,he participants completed a packet of questionnaires. Theyere mailed these questionnaires again approximately 20,0, 66, and 92 weeks after surgery and provided a postage-aid envelope to facilitate return. The packet included theollowing measures:
Rosenberg Self-Esteem scale: self-esteem was as-sessed using the Rosenberg Self-Esteem scale.This 10-item scale provides a global measure ofself-esteem. Lower scores indicate greater self-es-teem [22].
Beck Depression Inventory-II: the presence of depres-sive symptoms was measured with the Beck De-pression Inventory-II, the most widely used mea-sure of depressive symptoms. Greater scores reflectgreater dysphoria [23].
Positive and Negative Affect Scale: mood state, bothpositive and negative, was also assessed using thePositive and Negative Affect Scale. The measurehas separate subscales for both positive and nega-tive affect, with higher scores reflecting a greaterfrequency of the identified mood [24].
Eating Inventory: the Eating Inventory is a 51-itemself-report inventory that assesses 3 factors: (1)cognitive restraint; (2) disinhibition; and (3) hun-ger. This widely used inventory measures the de-gree to which persons exert conscious control overfood intake and the extent to which such control isdisrupted by internal or external factors [25].
Block 98 Food Frequency Questionnaire: The Block98 Food Frequency Questionnaire provides esti-mates of daily calorie intake and macronutrientcomposition by asking respondents to describetheir food intake during the past 2 months. Thequestionnaire has excellent reliability and has beenvalidated against multiple 4-day and 7-day foodrecords [26,27].
Dietary adherence: At each assessment point, partic-ipants were asked, “How well are you followingthe diet plan given to you by the dietitian?” Theyresponded on a 9-point Likert scale that rangedfrom 1 (“not well at all”) to 9 (“very well”).
Weight: Weight was self-reported by the participants
at all postoperative assessments.
P
iabolsdpuactv
S
oNoaoadsb
S
df
p1dpsdo
omw(aoc(
icae
adtframp
ovamia
avae2adwteU2
R
P
iTy5aa8AoO3vpt
C
alF
642 D. B. Sarwer et al. / Surgery for Obesity and Related Diseases 4 (2008) 640–646
reoperative dietary counseling
Approximately 2 weeks before surgery, the study partic-pants met with 1 of the program’s registered dietitians. Ingroup session, patients were instructed in the dietary and
ehavioral changes believed necessary for a successful post-perative outcome. They were instructed to begin with aiquid diet for the first 2 weeks after surgery. They thenlowly progressed to small portions of pureed or soft foodsuring the next 2–4 weeks. At approximately 2 monthsostoperatively, patients typically returned to a diet of reg-lar foods, consisting of several 1–2-oz. meals totalingpproximately 1000–1200 kcal/d. Patients also were en-ouraged to take a daily multivitamin, increase protein in-ake, and avoid sweets, fats, and other foods that can triggeromiting and dumping.
urgical procedure
Gastric bypass surgery was performed as either an openr a laparoscopic procedure by 1 of 2 surgeons (S.E.R. and.N.W.). Both surgeons performed essentially the sameperation, with the formation of a small gastric pouch withcapacity of approximately 30 cm3. The second step of theperation was the formation of a Roux-en-Y jejunal limb ofpproximately 70 cm, on average. Postoperative weight lossid not differ by surgeon or technique (open or laparo-copic). Thus, the results from both surgeons were com-ined in all analyses.
tatistical analysis
Descriptive statistics are presented as the mean � stan-ard deviation for continuous variables and as percentagesor categorical variables.
All 200 participants completed a baseline packet and �1ostoperative packet. We received 198 packets at week 20,47 at week 40, 92 at week 66, and 112 at week 92. Theeclining response occurred despite repeated mailings, tele-hone calls, and e-mail letters (when available). These as-essment points were selected, because this study was con-ucted in parallel with a study of behavioral treatment ofbesity, the results of which are not presented in this report.
To compare the mean percentage of change in weightver the 4 points (weeks 20, 40, 66, and 92), repeated-easures analyses were conducted using a means modelith the Statistical Analysis Systems Mixed procedure
SAS Institute, Cary, NC). An unstructured variance-covari-nce form in repeated measurements was assumed for eachutcome, and estimates of the standard errors were used toonduct the tests and construct 95% confidence intervalsCIs).
In the mixed model analyses, we considered the follow-ng variables as candidate predictors of the percentage ofhange in weight loss: demographic variables (age, gender,nd ethnicity); preoperative psychosocial variables (self-
steem, depressive symptoms, positive affect and negative affect); preoperative eating behavior (cognitive restraint,isinhibition, and hunger); preoperative baseline dietary in-ake (daily caloric intake and percentage of calories fromat, protein, carbohydrate, and sweets/desserts); and self-eported dietary adherence. The outcome variable (percent-ge of weight loss) satisfied the normality assumption of theixed models, and residual analyses confirmed an appro-
riate fit of the mixed models.To investigate how the behavioral variables changed
ver time, each variable was considered as the outcomeariable in a mixed model analysis. Using a Bonferronidjustment for the 10 pairwise comparisons, these mixedodel analyses were also used to identify significant-with-
n-mean differences between the time points for each vari-ble.
In the mixed model analysis with postoperative dietarydherence as the outcome, each of the other behavioralariables was considered as an independent predictor vari-ble to assess its individual association with dietary adher-nce. Furthermore, postoperative dietary adherence at week0 was split at the median (as “high” and “low” dietarydherence) and entered into a mixed model as the indepen-ent variable to examine its contribution to the change ineight loss from week 20 to week 92. We chose to split
hese groups at the median, because no standard of adher-nce to the postoperative diet has been widely accepted.nless otherwise noted, all statistical tests described were-tailed with an alpha level of �0.05 considered significant.
esults
articipants’ characteristics
The demographic and descriptive variables are presentedn Table 1. Most (n � 164, 82%) participants were women.he women had a mean preoperative age of 42.6 � 9.9ears, weight of 139.4 � 25.6 kg, and body mass index of1.4 � 9.0 kg/m2. The men (n � 36) had a mean preoper-tive age of 45.7 � 9.4 years, weight of 181.3 � 37.2 kg,nd body mass index of 55.5 � 10.0 kg/m2. Approximately7% of all participants were European American, 9% werefrican American, and the remainder were of other ethnicrigins. Participants reported 14.0 � 2.3 years of education.f the 200 participants, 49.5% reported being married,4.5% were single, and the remainder were separated, di-orced, or widowed. Finally, 83% indicated they were em-loyed, 6.5% were receiving disability, and 9.5% indicatedhey were unemployed or retired.
hanges in weight
According to the mixed model analysis that included allvailable data at each point, the mean percentage of weightoss changed significantly over time (Fig. 1a, overall time
� 223, P �.0001). Participants, on average, had lost
pproximately 25.5% (95% CI 24.6–26.3) of their body
w3apfs(
C
sbmtaaTbr((s2b
paTb(ffn
pfrNc
2ap5INpwwipetattc
F(
TP
C
E
CCMM
M
M
M
643D. B. Sarwer et al. / Surgery for Obesity and Related Diseases 4 (2008) 640–646
eight at 20 weeks after surgery, 35.0% (95% CI 33.8–6.1) at 40 weeks, 39.1% (95% CI 37.7–40.6) at 66 weeks,nd 39.4% (95% CI 37.2–41.7) at 92 weeks. The meanercentage of change in weight loss at week 20 differedrom all other points, and all other pairwise means wereignificantly different, except for week 66 vs. week 92P �.0001 for all significant pairwise comparisons).
hanges in behavioral variables
Table 2 lists the mixed model-based mean value �tandard error of the behavioral variables of interest ataseline (preoperatively) and at the 4 postoperative assess-ent points. Consistent with previous investigations, par-
icipants reported significant improvements in self-esteemnd depressive symptoms, as well as positive and negativeffect, after surgery (by postoperative week 20, all P �.001).hese improvements remained significantly different fromaseline at postoperative week 92 (all P �.001). Cognitiveestraint had increased significantly at postoperative week 20P �.001) and remained significantly different at week 92P �.001). Self-reports of hunger and disinhibition hadignificantly decreased from baseline to postoperative week0 (P �.001) and also remained significantly different fromaseline at week 92 (P �.001).
The total caloric intake had decreased by �50% byostoperative week 20 (P �.001), the first assessment pointt which participants had returned to a diet of regular food.he total daily calories, however, increased significantlyy approximately 150 kcal/d from week 20 to week 92P �.001). The percentage of calories from sweets/dessertsollowed a similar pattern, with a sizable decrease in the firstew months after surgery (P �.001) and a small, but sig-
able 1articipant characteristics
haracteristic Total sample(n � 200)
Men(n � 36)
Women(n � 164)
thnicity (%)EuropeanAmerican
87.5 97.2 85.4
African American 9.5 2.8 11.0Other 2.0 0 2.4
urrently employed 82.7 80.0 83.3urrently married 49.5 63.9 46.3ean education (y) 14.0 � 2.3 14.6 � 2.7 13.9 � 2.2ean age at surgery(y)
43.2 � 9.8 45.7 � 9.4 42.6 � 9.9
ean baseline height(cm)
167.6 � 9.5 180.7 � 8.4 164.7 � 6.9
ean baseline weight(kg)
146.9 � 32.3 181.3 � 37.2 139.4 � 25.6
ean baseline BMI(kg/m2)
52.1 � 9.3 55.5 � 10.0 51.4 � 9.0
BMI � body mass index.Data presented as mean � standard deviation, unless otherwise noted.
ificant (P �.001), increase from week 20 to week 92. The d
ercentage of calories from protein increased significantlyrom baseline to postoperative week 20 (P �.001), but hadeturned to near baseline levels by postoperative week 92.o significant changes were found in the percentage of
alories from fat and carbohydrates after surgery.The mean self-reported dietary adherence level at week
0 was 6.44 (95% CI 6.16–6.73). The self-reported dietarydherence had decreased significantly at the subsequentostoperative weeks (5.74 at week 40, 5.54 at week 66, and.36 at week 92; P �.0004). The baseline Beck Depressionnventory-II, Rosenberg Self-Esteem Scale, Positive andegative Affect Scale (negative), daily caloric intake, andercentage of calories from sweets correlated negativelyith changes in postoperative dietary adherence througheek 92, and the Positive and Negative Affect Scale (pos-
tive), cognitive restraint, and percentage of calories fromrotein were positively associated with changes in postop-rative dietary adherence (P �.03 for all). The change inhese variables over time, however, was not associated with
change in postoperative dietary adherence from week 20o week 92. The change in weight loss from week 20hrough week 66 was significantly associated with thehanges in postoperative dietary adherence (P �.02).
ig. 1. (a) Model-based mean percentage of weight loss over time.b) Model-based mean percentage of weight loss over time stratified by
ietary adherence group.
P
(Paatta(2hwg9ewC(mabrsaes1sg
C
chT(t8oale4
D
dboonbvrtrw
TP
V
DP
M
644 D. B. Sarwer et al. / Surgery for Obesity and Related Diseases 4 (2008) 640–646
redictors of weight loss
Of the predictor variables of interest, only 3—genderF � 6.4, P � .01), baseline cognitive restraint (F � 8.8,
� .003), and self-reported dietary adherence at postoper-tive week 20 (F � 9.3, P � .003)—were significantlyssociated with postoperative weight loss. To examine howhe percentage of weight loss over time differed accordingo the levels of self-reported dietary adherence at postoper-tive week 20, we split dietary adherence at the medianscore 7). At week 20, the low-adherence group had lost6% of their initial weight and the high-adherence groupad lost 27% of their initial weight. A mixed model analysisas then conducted to compare the low and high-adherenceroups in the percentage of weight loss at weeks 40, 66, and2. From week 20 to week 40, those high in dietary adher-nce lost an additional 13.0% (95% CI 11.7–14.4) of theireight, significantly greater than the additional 10.6% (95%I 9.2–12.0) lost by those with poorer dietary adherence
P � .02). At week 66, the weight loss for the 2 groups,easured from week 20, was 18.1% (95% CI 16.0–20.1)
nd 14.3% (95% CI 12.1–16.5), respectively (P � .01 foretween-group differences). By week 92, both groups hadegained some weight, but the high-adherence group hadtill lost significantly more weight than those in the low-dherence group at week 92. Those high in dietary adher-nce had lost 16.2% (95% CI 13.7–18.7) of their weightince week 20, compared with only 11.7% (95% CI 9.0–4.4) for those low in dietary adherence (P � .02), repre-enting a 28% difference in weight loss between the 2
able 2ostoperative changes in dietary adherence, psychosocial variables, macro
ariable Baseline Postopera
20
ietary adherence — 6.5 �sychosocial variablesBDI 12.3 � 0.6* 6.0 �RSE 20.5 � 0.4* 17.6 �PANAS
Positive 30.4 � 0.6* 34.2 �Negative 21.7 � 0.6* 16.8 �
Eating Inventory subscalesCognitive restraint 8.3 � 0.3* 13.4 �Disinhibition 10.0 � 0.3* 5.2 �Hunger 7.1 � 0.3* 3.1 �
acronutrient intakeDaily calories 2390.9 � 99.0* 1172.9 �
% from fat 41.3 � 0.6* 39.9 �% from protein 15.2 � 0.3* 16.5 �% from carbohydrates 44.1 � 0.7* 44.8 �% from sweets 18.5 � 0.9* 9.3 �
BDI � Beck Depression Inventory-II; RSE � Rosenberg Self-EsteemData presented as mean � standard error.* Significant differences across time at P � .005.
roups (Fig. 1b). m
hanges in dietary adherence
We were also interested in whether dietary adherencehanged over time. At week 20, the low-adherence groupad a mean adherence level of 4.59 (95% CI 4.36–4.82).his had not change significantly at weeks 40, 66, and 92
mean level 4.56, 4.64, and 4.05, respectively). At week 20,he high-adherence group had a mean adherence level of.00 (95% CI 7.80–8.22), significantly different from thatf the remaining weeks (6.79 at week 40, 6.34 at week 66,nd 6.52 at week 92). At each week, the mean adherenceevels of the 2 adherence groups differed significantly fromach other (P �.005 for between-differences at weeks 20,0, 66, and 92).
iscussion
The results of the present study add to a growing body ofata on the characteristics associated with weight loss afterariatric surgery. Our participants lost approximately 25%f their preoperative body weight within the first 20 weeksf gastric bypass surgery. They lost another 10% during theext 20 weeks and almost 40% of their initial body weighty the second postoperative year. Of the potential predictorariables of interest investigated, gender, baseline cognitiveestraint, and self-reported dietary adherence at postopera-ive week 20, when participants had returned to eatingegular food, were significant predictors of the percentage ofeight loss over time.Men who underwent bariatric surgery lost significantly
t intake
ek
40 66 92
5.7 � 2.2 5.6 � 2.5 5.4 � 2.2
7.0 � 0.7* 7.1 � 0.7* 8.0 � .8*16.9 � 0.4* 16.7 � 0.5* 16.7 � 0.5*
34.4 � 0.7* 34.4 � 0.8* 33.7 � .8*17.9 � 0.7* 17.9 � 0.8* 18.1 � 0.7*
12.9 � 0.4* 12.4 � 0.4* 12.3 � 0.4*5.1 � 0.3* 5.2 � 0.3* 5.5 � 0.3*3.4 � 0.3* 3.8 � 0.3* 3.7 � 0.3*
1189.5 � 54.2* 1273.4 � 56.3* 1358.1 � 60.5*40.2 � 0.8* 42.0 � 0.9* 41.6 � 0.9*16.0 � 0.3* 15.6 � 0.4* 14.9 � 0.3*44.6 � 0.9* 43.2 � 0.9* 43.4 � 0.9*11.7 � 0.8* 13.3 � 0.9* 13.3 � 0.9*
ANAS � Positive and Negative Affect Scale.
nutrien
tive we
2.0
0.5*0.4*
0.6*0.5*
0.3*0.2*0.2*
46.5*0.7*0.3*0.7*0.7*
scale; P
ore weight over time than did women. This result is not
pmgtttg
heewcfpdaawldap.P0db
peotwt49hlricidrc
ddnsttt
et
apetvcactepgadtciid
ppccidrytorwspsicciecc
pcppeait
645D. B. Sarwer et al. / Surgery for Obesity and Related Diseases 4 (2008) 640–646
articularly surprising, because men have been found to loseore weight than women in other studies of bariatric sur-
ery, as well as studies of behavioral and pharmacologicreatments for obesity [28]. This difference is typically at-ributed to metabolic differences between the genders, al-hough obese men, and their response to weight loss, sur-ical or otherwise, have been studied far less frequently.
The contributions of baseline cognitive restraint and ad-erence to the postoperative diet represent novel and inter-sting findings. Those individuals who reported greater lev-ls of cognitive restraint at baseline experienced greatereight loss postoperatively. Cognitive restraint is typically
haracterized as an individual’s ability to intentionally limitood intake, typically to prevent weight gain [25]. Given theositive association between baseline cognitive restraint andietary adherence found in our study, it could be that thebility to restrict food intake before surgery predicts thebility to adhere to the rigorous postoperative diet. As ahole, individuals in the present study reported relatively
ow levels of cognitive restraint preoperatively and could beescribed as “unrestrained eaters.” However, we found anssociation between baseline cognitive restraint and theercentage of daily calories from sweets (r � �0.30, P �0003), percentage of daily calories from fat (r � �0.21,
� .01), and percentage of daily calories from protein (r �.20, P � .01), suggesting that those with greater levels ofietary restraint had consumed comparatively healthier dietsefore surgery.
The self-reported adherence to the postoperative diet atostoperative week 20, when participants had returned toating regular food, was also associated with greater post-perative weight loss. Those individuals who scored greaterhan the median in dietary adherence, compared with thoseho scored less than the median, experienced a weight loss
hat was 2.4 percentage points greater at postoperative week0 and 3.8 percentage points greater at week 66. By week2, both groups had regained some weight. However, thoseigh in self-reported dietary adherence achieved a weightoss that was 4.5 percentage points greater than those whoeported less adherence to the postoperative diet, represent-ng a 28% greater weight loss. Those individuals initiallyategorized as high in dietary adherence reported a signif-cant deterioration in their adherence to the postoperativeiet during the course of the study, although their adherenceemained significantly greater at week 92 than those initiallyategorized as low in dietary adherence.
At present, no accepted standards for the postoperativeiet after bariatric surgery are available. Adherence to theramatically reduced portion sizes is believed to be a sig-ificant challenge for many patients. The findings from thistudy, as have others [8,14–19], suggest that although pa-ients often are able to decrease their caloric intake duringhe first postoperative year, the caloric intake increases over
ime. The present study is the first, however, to provide svidence that adherence to the postoperative diet is predic-ive of postoperative changes in weight.
Baseline self-esteem and depressive symptoms, as wells positive and negative affect, were not associated withostoperative weight loss. These characteristics were, how-ver, associated with changes in dietary adherence duringhe postoperative period. In general, studies that have in-estigated the relationship between baseline psychosocialharacteristics and/or psychopathologic findings after bari-tric surgery have been contradictory [4–7]. This lack of aonclusive association has led some to question the value ofhe assessment of preoperative psychosocial status. Thesevaluations typically assess the presence of formal psycho-athologic findings that might contraindicate bariatric sur-ery; but they also evaluate the environmental influencesnd psychosocial factors that might have contributed to theevelopment of extreme obesity, and, perhaps most impor-antly, their potential relationship with postoperative out-ome [20]. The results of the present study underscore themportance of a preoperative assessment of eating behav-ors, whether conducted by a mental health professional orietitian.
Consistent with other investigations [4–6], the partici-ants experienced improvements in psychosocial statusostoperatively. Self-esteem improved, positive affect in-reased, and negative affect and depressive symptoms de-reased. Participants also experienced changes in their eat-ng behavior. Dietary restraint increased and hunger andisinhibition had decreased 20 weeks after surgery andemained at these levels through the second postoperativeear. Participants also reported a postoperative reduction inotal caloric intake, as well as the percentage of daily cal-ries from sweets and desserts. These findings are likelyelated to the restrictive aspects of gastric bypass surgery, asell as concerns about the “dumping syndrome” after con-
umption of sugar. A significant increase occurred in theercentage of daily calories from protein at 20 weeks afterurgery; however, by 92 weeks postoperatively, proteinntake had returned to baseline levels. However, the overallhange from baseline was modest, and its clinical signifi-ance is unclear. The lack of a lasting change in proteinntake is somewhat concerning, given that the patients werexplicitly instructed during their preoperative nutritionounseling session to increase the amount of protein theyonsumed postoperatively.
Although it has provided important new information, theresent study had a number of limitations. Perhaps mostritically, we experienced significant attrition. Only 56% ofarticipants completed the final assessment, despite re-eated mailings and telephone calls and/or email lettersncouraging them to complete the study. High rates ofttrition are a relatively common experience in obesity stud-es and represent a significant threat to the integrity ofreatment outcomes studies. However, in a post hoc analy-
is, we found no significant differences in the baseline
vrpmr
tlkssboidspfiwtco
D
m
R
[
[
[
[
[
[
[
[
[
[
[
[
[[
[
[
[
[
[
[
646 D. B. Sarwer et al. / Surgery for Obesity and Related Diseases 4 (2008) 640–646
ariables of interest between those who did and did notemain in the study. Although the mixed model used in theresent study is a recommended analytic method to handleissing data, it is not a perfect substitute for lower attrition
ates.Our reliance on self-report measures was another limita-
ion. The self-reported weights used in the present study areikely to have overstated participants’ weight losses by 2–3g [29]. The postoperative weight loss, however, remainedubstantial even with this likely overestimation. Althoughelf-report measures of psychological symptoms and eatingehaviors are widely used, they are not the ideal measuresf psychopathologic findings or dietary intake. Future stud-es should strive to augment these assessments with vali-ated clinical interviews. Although the results of the presenttudy suggest that cognitive restraint and adherence to theostoperative diet are related to changes in weight in therst 2 postoperative years, their relationship to longer termeight loss is unknown. Regardless, these findings suggest
he possible utility of pre- and/or postoperative dietaryounseling interventions to improve dietary adherence andptimize postoperative outcomes.
isclosures
The authors claim no commercial associations thatight be a conflict of interest in relation to this article.
eferences
[1] Santry HP, Gillen DL, Lauderdale DS. Trends in bariatric surgicalprocedures. JAMA 2005;294:1909–17.
[2] Buchwald H, Avidor Y, Braunwald E, et al. Bariatric surgery: asystematic review and meta-analysis. JAMA 2004;292:1724–34.
[3] Sarwer DB, Foster GD, Wadden TA. Treatment of obesity I: adultobesity. In Thompson JK, editor. Handbook of eating disorders andobesity. Hoboken, NJ: John Wiley & Sons; 2004. p. 421–42.
[4] Bocchieri LE, Meana M, Fisher BL. A review of psychosocial outcomesof surgery for morbid obesity. J Psychosom Res 2002;52:155–65.
[5] Herpertz S, Kielmann R, Wolf AM, Langkafel M, Senf W, Hebe-brand J. Does obesity surgery improve psychosocial functioning? Asystematic review. Int J Obes Relat Metab Disord 2003;27:1300–14.
[6] Sarwer DB, Wadden TA, Fabricatore AN. Psychosocial and behav-ioral aspects of bariatric surgery. Obes Res 2005;13:639–48.
[7] van Hout GC, van Oudheusden I, van Heck GL. Psychological profileof the morbidly obese. Obes Surg 2004;14:479–88.
[8] Sjöstrom L, Lindroos AK, Peltonen M, et al. Lifestyle, diabetes, andcardiovascular risk factors 10 years after bariatric surgery. N Engl
J Med 2004;351:2683–93.[9] Hsu LK, Benotti PN, Dwyer J, et al. Nonsurgical factors that influencethe outcome of bariatric surgery. Psychosom Med 1998;60:338–46.
10] Hsu LK, Mulliken B, McDonagh B, et al. Binge eating disorder inextreme obesity. Int J Obes Relat Metab Disord 2002;26:1398–403.
11] Kalarchian MA, Marcus MD, Wilson GT, Labouvie EW, Brolin RE,LaMarca LB. Binge Eating among gastric bypass patients: a long-term follow-up. Obes Res 2002;12:270–5.
12] Sugerman HJ, Starkey JV, Birkenhauer R. A randomized prospectivetrial of gastric bypass versus vertical banded gastroplasty for morbidobesity and their effects on sweet versus non-sweets eaters. Ann Surg1987;205:613–24.
13] Sugerman HJ, Londrey GL, Kellum JM. Weight loss with verticalbanded gastroplasty and Roux-en-Y gastric bypass with selective vs.random assignment. Am J Surg 1989:157:93–102.
14] Lindroos AK, Lissner L, Sjöstrom L. Weight change in relation tointake of sugar and sweet foods before and after weight reducinggastric surgery. Int J Obes Relat Metab Disord 1996;20:634–43.
15] Malone M, Alger-Mayer S. Binge status and quality of life aftergastric bypass surgery: a one-year study. Obes Res 2004;12:473–81.
16] Anderson T, Larsen U. Dietary outcome in obese patients treated witha gastroplasty program. Am J Clin Nutr 1989;50:1328–40.
17] MacLean LD, Rhode BM, Shizgal HM. Nutrition following gastricoperations for morbid obesity. Ann Surg 1983;198:347–55.
18] Miskowiak J, Honore K, Larsen L, Andersen B. Food intake beforeand after gastroplasty for morbid obesity. Scand J Gastroenterol1985;20:925–8.
19] Naslund I, Jarnmark I, Anderson H. Dietary intake before and aftergastric bypass and gastroplasty for morbid obesity in women. Int JObes Relat Metab Disord 1988;12:503–13.
20] Wadden TA, Sarwer DB. Behavioral assessment of candidates forbariatric surgery: a patient-oriented approach. Obesity 2006;14(suppl2):51S–52S (note: co-publication in Surgery for Obesity and RelatedDisorders 2006;2:171–9).
21] Wadden TA, Foster GD. Weight and Lifestyle Inventory (WALI).Obesity 2006;14(suppl 2):99S–118S (note: co-publication in Surgeryfor Obesity and Related Disorders 2006;2:180–99).
22] Rosenberg M. Conceiving the self. York: Basic Books; 1979.23] Beck AT, Steer RA. BDI Beck Depression Inventory manual. San
Antonio: Harcourt Brace; 1993.24] Watson D, Clark LA. Development and validation of brief measures
of positive and negative affect: the PANAS subscales. J Personal SocPsychol 1988;54:1063–70.
25] Stunkard AJ, Messick S. Eating inventory manual. San Antonio:Harcourt Brace; 1988.
26] Block G, Woods M, Potosky A, Clifford C. Validation of a self-administered diet history questionnaire using multiple diet records.J Clin Epidemiol 1990;43:1327–35.
27] Sorbell J, Block G, Koslowe R, Tobin J, Andres R. Validation ofretrospective questionnaire assessing diet 10–15 years ago. Am JEpidemiol 1989;130:173–87.
28] Wadden TA, Foster GD, Letizia KA, Stunkard AJ. A multicenterevaluation of a proprietary weight reduction program for the treat-ment of marked obesity. Arch Intern Med 1992;152:961–6.
29] Tell GS, Jeffery RW, Kramer FM, Snell MK. Can self-reported bodyweight be used to evaluate long-term follow-up of a weight loss
program? J Am Diet Assoc 1987;87:1198–201.