Food cue-induced craving in individuals with bulimia nervosa and binge-eating disorder
Food cue-induced craving in individuals with bulimia nervosa and binge-eating disorder
Adrian Meule 0 1
Carolyn KuÈ ppers 1
Louisa Harms 1
Hans-Christoph Friederich 1
Ulrike Schmidt 1
Jens Blechert 0 1
Timo Brockmeyer 1
0 Department of Psychology, University of Salzburg , Salzburg , Austria , 2 Centre for Cognitive Neuroscience, University of Salzburg , Salzburg , Austria , 3 Department of General Internal Medicine and Psychosomatics, Center for Psychosocial Medicine, Heidelberg University Hospital , Heidelberg, Germany , 4 Department of Psychosomatic Medicine and Psychotherapy, Medical Faculty, Heinrich-Heine-University D uÈsseldorf , D uÈsseldorf, Germany , 5 Section of Eating Disorders, Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London , London , United Kingdom , 6 Eating Disorders Unit, South London and Maudsley NHS Foundation Trust , London , United Kingdom , 7 Department of Clinical Psychology and Psychotherapy, Institute of Psychology, University of Goettingen , Goettingen , Germany
1 Editor: Amparo del Pino-Gutierrez, Universitat de Barcelona , SPAIN
Individuals with bulimia nervosa (BN) or binge-eating disorder (BED) experience more frequent and intense food cravings than individuals without binge eating. However, it is currently unclear whether they also show larger food cue-induced increases in craving (i.e., food cue reactivity) than those without binge eating, as suggested by conditioning theories of binge eating. A group of individuals with BN or BED (binge-eating group, n = 27) and a group of individuals with low trait food craving scores and without binge eating (control group, n = 19) reported their current food craving before and after a food cue exposure. Although food craving intensity significantly increased in both groups, this increase was significantly stronger in the binge-eating group than in the control group. This result is in line with conditioning models of binge eating that propose that food cues are conditioned stimuli that elicit a conditioned response (e.g., food craving) and that this association is stronger in individuals with binge eating. As food craving increased in individuals with low trait food craving scores as wellÐalthough to a lesser extentÐprevious null results might be explained by methodological considerations such as not screening control participants for trait food craving.
Data Availability Statement: All relevant data are
within the paper and its Supporting Information
Funding: This research was partially supported by
grants from the Swiss Anorexia Nervosa
Foundation (#29-13; #44-15). Ulrike Schmidt
receives salary support from the National Institute
for Health Research (NIHR) Mental Health
Biomedical Research Centre at South London &
Maudsley NHS Foundation Trust and King's
College London. She is also supported by an NIHR
In terms of classical conditioning, food intake may be considered an unconditioned stimulus
and its metabolic effects unconditioned responses. Cues that reliably signal food intake (e.g.,
the sight, smell, and taste of food) may start to act as conditioned stimuli that can trigger
conditioned responses. This learned food cue reactivity can manifest in several
objectively-measurable physiological responses (e.g., increases in salivary flow, heart rate) upon exposure to
food or food cues, yet an essential element of food cue reactivity is a subjective experience of
an intense desire to eat the food (i.e., craving) [
Senior Investigator Award. The views expressed in
this publication are those of the authors and not
necessarily those of the NHS, the NIHR, or the
Department of Health. The funders had no role in
study design, data collection and analysis, decision
to publish, or preparation of the manuscript.
The conditioning model of binge eating proposes that individuals with binge eating display
higher reactivity to food cues than individuals without binge eating, which ultimately leads to
excessive food intake [
]. However, when examining studies that measured self-reported food
craving, it appears that the assumption of larger food cue-induced increases in craving in
individuals with binge eating (e.g., persons with bulimia nervosa [BN] or binge-eating disorder
[BED]) has not been reliably established.
First, individuals with binge eating do indeed report higher trait food craving (i.e.,
experience more frequent and intense food cravings in general) and higher state food craving (i.e.,
experience more intense food craving in the moment of data collection) than individuals
without binge eating [
]. However, such studies cannot answer the question of whether
individuals with BN or BED show higher food cue reactivityÐin terms of food cue-induced increases
in cravingÐthan healthy controls. Second, some studies reported higher food craving in
individuals with BN or BED than in healthy controls after a food cue exposure, but did not
measure baseline levels of food craving [
]. Thus, whether craving increases were larger in
participants with BN or BED than in controls cannot be inferred from these studies. Third,
studies that included a food cue exposure with pre- and post-exposure measurements of food
craving and compared individuals with BN and/or BED with healthy controls did not find a
significant interaction between groups and measurements, that is, food craving or desire to
binge increased equally in all groups during food cue exposure [7±14].
In conclusion, while individuals with BN or BED report more frequent and intense food
cravings in general than individuals without binge eating, there is no compelling evidence that
these differences reflect an elevated reactivity to food cues in terms of larger increases of food
craving intensity in response to food cues (which would explain their difficulties in controlling
food intake). Therefore, we tested whether a group of individuals with BN or BED would
demonstrate stronger increases in momentary food craving during a food cue exposure than
individuals without binge eating. Previous null findings may be partially due to the fact that
control participants were not screened for trait food craving levels, which would also be
associated with elevated food cue reactivity [
]. Thus, to ensure that control participants did not
have any sub-threshold eating disorder symptoms or any eating-related psychopathology, we
used a control group of individuals without binge eating and low levels of trait food craving.
Materials and methods
The study was approved by the institutional review board of the Medical Faculty of the
University of Heidelberg. Participants provided written informed consent before commencing the
study and received financial compensation for their participation in the study. Fourteen
individuals with BN and 13 individuals with BED, who took part in a larger research project [
and who were all recruited at the same study site, participated in this study (binge-eating
group). Nineteen individuals without any eating disorder or elevated trait food craving scores
were used as control group [
]. Sample characteristics are displayed in Table 1. In the
bingeeating group, 66.7% of participants had normal weight (n = 18), 14.8% were overweight
(n = 4), and 18.5% were obese (n = 5), according to the guidelines by the World Health
Organization . In the control group, 78.9% of participants had normal weight (n = 15), 15.8%
were overweight (n = 3), and 5.3% were obese (n = 1).
All participants were recruited through websites, circular mails, advertising posters and
advertisements in local and social media. Women and men were eligible for participation in
the study if they were aged 18 years or above and had a body mass index 18.5 kg/m2.
Diagnostic assessment in the binge-eating group was based on the Structured Clinical Interview for
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Binge-eating group (n = 27)
M = 30.0 (SD = 11.5)
n = 24 (88.9%)
n = 26 (96.3%)
M = 24.2 (SD = 5.27)
M = 3.01 (SD = 0.81)
M = 14.7 (SD = 7.14)
M = 40.1 (SD = 12.4)
M = 48.6 (SD = 13.7)
Control group (n = 19)
M = 24.4 (SD = 3.20)
n = 17 (89.5%)
n = 17 (89.5%)
M = 22.6 (SD = 3.80)
M = 0.87 (SD = 0.70)
M = 34.0 (SD = 11.8)
M = 38.7 (SD = 11.8)
t(31.5) = 2.42, p = .021, d = 0.62
χ2(1) = 0.004, p = .950, d = 0.02
χ2(1) = 0.85, p = .356, d = 0.27
t(43.9) = 1.21, p = .233, d = 0.34
t(44) = 9.30, p < .001, d = 2.79
t(44) = 1.67, p = .102, d = 0.50
t(44) = 2.54, p = .015, d = 0.76
DSM-5 Disorders [
]. Exclusion criteria for the binge-eating group were: medical (e.g., severe
electrolyte abnormalities) or psychiatric (e.g., acute suicidality) instability, the need for
immediate inpatient treatment, substance dependence, psychosis, bipolar disorder, borderline
personality disorder, psychotropic medication use, severe learning disability or inability to speak
fluent German, impacting on the person's ability to complete study assessments. Use of
selective serotonin reuptake inhibitors was not an exclusion criterion when medication was stable
(i.e. at least 14 days of continuous use). Participants in the control group were invited for
laboratory testing if they scored in the lower third on the German version of the Food Cravings
] in a sample of n = 358 volunteers, did not report any binge eating
episodes as assessed with the Eating Disorder Examination–Questionna ire (EDE±Q) [
had no current or prior psychotherapeutic or psychopharmacological treatment.
Food cue exposure. A five-minute video clip was used to induce food craving. The video
contains clips from television advertisements including palatable (both junk and non-junk)
foods. The video has been previously used by Kekic and colleagues who reported that the
foods shown were rated as highly appetizing and that hunger was significantly increased after
watching the video [
Food Cravings Questionnaire±State (FCQ±S). The German version of the FCQ±S [
was used for measuring momentary food craving intensity. The scale has 15 items (e.g., ªI have
an intense desire to eat [one or more specific foods].º). Participants are asked to indicate on a
five-point scale the extent to which they agree with each statement right now, at this very
moment, ranging from strongly disagree to strongly agree [
]. Thus, total scores can range
between 15 and 75. Cepeda-Benito and colleagues [
] originally proposed a five-factor model
of the FCQ±S. However, as the scale usually has very high internal reliability and as studies
that examined its factor structure have been inconsistent [9, 21, 25±27], only the total score
was used in the analyses. Internal reliability was high both before (α = .923) and after (α =
.943) food cue exposure.
Participants were asked to refrain from eating food, drinking caffeine-containing beverages,
and smoking in the two hours before the assessment. They were tested in the laboratory
individually and completed the FCQ±S. Following this, the five-minute video clip was shown as
food cue exposure. Subsequently, participants completed the FCQ±S again. Finally, body
height and weight were measured.
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Differences between groups were tested with independent samples t-tests (age, body mass
index, EDE±Q scores) and χ2-tests (sex, education). Regarding state food craving, an analysis
of variance for repeated measures was calculated with group (binge eating vs. control) as
between-subjects factor, measurement (before vs. after food cue exposure) as within-subjects
factor, and FCQ±S scores as dependent variable. All data analyses were conducted with IBM
SPSS Statistics Version 20.
The binge-eating group was older and had higher EDE±Q scores than the control group
(Table 1). Regarding state food craving, main effects of group (F(1,44) = 4.78, p = .034, ηp2 =
.098) and measurement (F(1,44) = 51.6, p < .001, ηp2 = .540) were qualified by a significant
group × measurement interaction (F(1,44) = 4.29, p = .044, ηp2 = .089). During the food cue
exposure, state food craving increased in both the binge-eating group (t(26) = 6.58, p < .001,
d = 0.64) and the control group (t(18) = 3.95, p = .001, d = 0.40). However, while groups did not
differ before the food cue exposure, the binge-eating group had higher state food craving than
the control group after the food cue exposure (Table 1; Fig 1).
Note that the age difference between groups was driven by participants with BED (M = 35.2
years, SD = 13.5) who were older than participants with BN (M = 25.2 years, SD = 6.62, t(17.2) =
2.41, p = .028, d = 0.95). As individuals with BED are commonly older than individuals with
BN on average, it would have been inappropriate to use age as covariate in the analysis of
]. Thus, we examined effects after excluding the three oldest participants (>50 years
old) such that the binge eating and control group did not differ in age any more (t(31.8) = 1.49,
p = .147, d = 0.42). Using these age-matched groups, the group × measurement interaction was
still significant (F(1,41) = 5.45, p = .025, ηp2 = .117).
Numerous studies showed that individuals with BN or BED experience more frequent and
more intense food cravings than persons without binge eating [3±6]. Yet, food cue-induced
craving did not differ in individuals with and without binge eating in the majority of studies
[7±14], raising the question whether cue reactivity is a useful concept to explain binge eating.
In the current study, individuals with and without binge eating did not differ in their
momentary food craving prior to food cue exposure. While it has been found that high trait
food craving scores (which individuals with BN or BED have) relate to higher state food
craving scores even without being exposed to food cues, this association is rather small [
a difference in state food craving between individuals with and without binge eating at baseline
may only be detected in larger samples.
During food cue exposure, state food craving intensity significantly increased in both
groups in the current study. However, individuals with BN or BED showed significantly larger
food cue reactivity in terms of self-reported craving. Of note, the food cue exposure induced
craving even in the control group who was explicitly recruited to have low trait food craving
scores. Therefore, we speculate that the lack of finding interactive effects of groups and
measurements in previous studies may be due to participant selection. For instance, several
previous studies only examined analogue samples, participants with sub-threshold BN/BED, or
very small samples [7±9, 11, 13]. Moreover, previous study designs may not have been sensitive
enough to detect differences in food cue-induced craving because high calorie foods appeal to
all humans and, likewise, induce craving in most individuals (as was demonstrated by craving
changes in our low trait food craving control group, in line with previous findings [
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Fig 1. Scores on the Food Cravings Questionnaire±State as a function of group (controls vs. individuals with bulimia nervosa or binge-eating disorder) before
and after food cue exposure. Error bars represent the standard error of the mean. Asterisks indicate p < .05.
Taken together, this suggests that differential effects of food cue exposure may only be
observed when groups are clearly separable; not only with regard to eating disorder pathology
but also with regard to other relevant aspects such as trait food craving scores.
Some methodological considerations limit interpretation of the current findings. First, the
sample was predominantly composed of non-obese women. Thus, findings may not be
applicable to men or individuals with obesity. Second, because of the small number of individuals
with BN and BED, they were combined to one binge-eating group. However, some differences
between individuals BN and BED have been noted, for example, with regard to binge eating
episodes characteristics [
]. Thus, future studies may reveal differences in food cue
reactivity between these groups as well. Third, we did not include a control group of high trait food
cravers without binge eating or any other eating-related psychopathology. Recruiting such a
control group may be hard to achieve because of the large overlap between trait food craving
scores and binge eating tendencies . Yet, as elevated food cue reactivity in high trait food
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cravers has been previously demonstrated [
], we speculate that such a control group would
show similar cue-induced increases in food craving to individuals with BN or BED.
Our data are in line with classical conditioning accounts which propose that food cues
represent conditioned stimuli that trigger a conditioned response (e.g., food craving) and that these
associations are stronger in individuals with binge eating than in healthy individuals. Although
we did not assess actual food intake in the current study, this elevated food cue reactivity may
ultimately increase the likelihood to engage in binge eating [
]. As food craving increased
in individuals with low trait food craving scores in the current study as well, previous null
results might be explained by methodological considerations such as not screening control
participants for trait food craving.
S1 Data. Study data.
Conceptualization: Timo Brockmeyer.
Data curation: Carolyn KuÈppers, Louisa Harms.
Formal analysis: Adrian Meule.
Funding acquisition: Hans-Christoph Friederich, Ulrike Schmidt, Timo Brockmeyer.
Investigation: Timo Brockmeyer.
Methodology: Timo Brockmeyer.
Schmidt, Timo Brockmeyer.
Supervision: Timo Brockmeyer.
Writing ± original draft: Adrian Meule.
Project administration: Carolyn KuÈppers, Louisa Harms, Hans-Christoph Friederich, Ulrike
Resources: Hans-Christoph Friederich, Ulrike Schmidt, Timo Brockmeyer.
Writing ± review & editing: Carolyn KuÈppers, Louisa Harms, Hans-Christoph Friederich,
Ulrike Schmidt, Jens Blechert, Timo Brockmeyer.
6 / 8
Wolz I, Sauvaget A, Granero R, Mestre-Bach G, Baño M, MartÂõn-Romera V, et al. Subjective craving
and event-related brain response to olfactory and visual chocolate cues in binge-eating and healthy
individuals. Sci Rep. 2017; 7: 1±10. https://doi.org/10.1038/s41598-016-0028-x
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