The Effect of Food Images on Mood and Arousal Depends on Dietary Histories and the Fat and Sugar Content of Foods Depicted

doi:10.4236/jbbs.2013.31001

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Journal of Behavioral and Brain Science, 2013, 3, 1-6

http://dx.doi.org/10.4236/jbbs.2013.31001 Published Online February 2013 (http://www.scirp.org/journal/jbbs)

The Effect of Food Images on Mood and Arousal Depends

on Dietary Histories and the Fat and Sugar Content

of Foods Depicted

Gregory J. Privitera*, Danielle E. Antonelli, Heather E. Creary

Department of Psychology, St. Bonaventure University, St. Bonaventure, USA

Email: *[email protected]

Received November 15, 2012; revised November 23, 2012; accepted February 16, 2013

ABSTRACT

Background: While brain imaging studies show that reward regions in the human brain that regulate reward-guided

behavior and integrate sensory modalities of smell, taste, and texture respond preferentially to high calorie foods, few

studies account for dietary histories or account for recent behavioral evidence showing preferential responding for fruits

(a low calorie food that tastes sweet). To address these concerns, the present study tested the hypothesis that images of

high/low fat and sugar foods, even sugary foods that are low calorie (i.e., fruits), will enhance emotional responsiveness

and that these changes may be related to dietary histories with fat and sugar intake. Method: Participants were shown 4

sets of 15 food images with each food image automatically timed every 9 s to transition to a new food image; partici-

pant pre-post mood and arousal was measured. The 4 sets of food images were high fat-high sugar (HFHS; desserts),

high fat-low sugar (HFLS; fried foods), low fat-high sugar (LFHS; fruits), or low fat-low sugar (LFLS; vegetables)

foods. To account for dietary histories, participants also completed estimated daily intake scales (EDIS) for sugar and

fat. Results: Mood and arousal significantly increased in all groups, except Group LFLS, and even in a group that was

low calorie but shown foods that taste sweet, i.e., Group LFHS. Interestingly, changes in arousal, but not mood, were

dependent on participant histories with sugar and fat intake. Conclusion: Changes in emotional responsiveness to food

images were nutrient-specific, which can be a more detailed level of analysis for assessing responsiveness to food im-

ages. Also, participant histories with sugar and fat should be taken into account as these histories can explain the

changes in arousal observed here.

Keywords: Fat; Sugar; Mood; Arousal; Dietary History

1. Introduction

Emotional regulation and eating behavior are indubitably

related [1-3], with many people allowing their emotions

to regulate food intake in order to maintain and promote

emotional well-being [4,5]. Emotional changes can often

lead to dietary changes, and even modifications of food

likes and dislikes [6]. Consumption of comfort foods, of-

ten high in fat and sugar, can lead to improved emotional

states [7], and yet intake of these foods in response to

emotions has been linked to the rising rates in obesity [8,9].

While much of the focus on the link between emotional

responsiveness and eating has been on physiological fac-

tors, more recent advances now focus on understanding

appetitive and cognitive factors, often linked to cortical

brain activity [10,11] that may also significantly contrib-

ute to the relationship between emotion and foodstuffs.

Brain imaging studies show clear evidence that re-

ward-related areas in the human brain respond preferen-

tially to the sight of high calorie vs. low calorie foods [10,

12]. A consistent pattern across studies shows that brain

regions in the temporo-insulo-opercular and orbitofrontal

areas—areas involved in regulating reward-guided be-

havior and integrating sensory modalities of smell, taste,

and texture [13]—are significantly more active during the

visual presentation of high calorie vs low calorie foods

[10,12,14,15]. Men show similar neuronal activation le-

vels regardless of hunger, whereas women show stronger

brain reward activation patterns when hungry, but not

when sated [12,16]. Interestingly, visual cortical sensory

processing is related to the sight of high-calorie, but not

low-calorie foods [17]. Overall, these findings suggest

that without ever consuming food, men and women have

positive, motivational experiences at the mere sight of

food, and show greater sensory (visual) processing of

high calorie vs low calorie foods.

Behavioral data show patterns similar to that from

neuroimaging studies. Women, particularly those who

*Corresponding author.

G. J. PRIVITERA ET AL.

are dieting, can be over-responsive to images of “forbid-

den” foods, such as chocolates and other high fat, high

sugar appetizing foods [18,19]; visual images of sweet

foods can also enhance ratings of deliciousness of those

foods [20]. Studies on the visibility and proximity of

foods show that participants eat more of candies (M&Ms)

if they are visible, even when these candies are not pro-

ximate, i.e., 2 m from the participant [21,22]. Similar

effects of visibility are observed with sweet-tasting fruits

(apples), but not bitter-tasting vegetables (carrots) [23].

Privitera et al. [23] suggest that the effect of visibility on

fruit, but not vegetable intake, may be specifically related

to perceived tastes, with foods perceived as tasting swee-

ter reported as more visually appealing, wanted, or moti-

vationally salient than foods perceived as tasting less

sweet, regardless of the actual number of calories.

In the present study, we extended findings from neuro-

biological and behavioral studies by testing the hypothe-

sis that nutrient-specific fat and sugar contents of food

will influence emotional responsiveness and that these

changes may be related to dietary histories with fat and

sugar intake. While many studies have looked at the ef-

fects of high vs. low calorie foods, these manipulations

have not looked at nutrient-specific levels of fat (high,

low) and sugar (high low), and have not controlled for

dietary histories, as is manipulated and controlled in the

present study. Also, because a growing body of research

shows that images of high calorie foods increases activity

of brain reward regions, we tested the prediction that we

should also observe a corresponding enhanced emotional

response to only the sight of these foods, as is often ob-

served when these foods are consumed [9].

2. Method

2.1. Participants

A total sample of 95 participants (40 men, 55 women)

was recruited through university classroom visits and

sign-up sheets. Participant characteristics were (M ± SD)

age (20.2 ± 1.2 years), weight (169.9 ± 21.8 pounds),

height (68.2 ± 2.5 inches), and BMI (25.9 ± 3.1 kg/m2).

In an initial screening phase, participants reported being

in general good health with no physical or doctor diag-

nosed food allergies, medical conditions including preg-

nancy, or dietary restrictions. Participants were told dur-

ing this initial screening not to eat within two hours of

the study because hunger states can influence respon-

siveness to food images [12,16]. Only participants who

did not eat within two hours of the study were included

in data analyses.

2.2. Measures and Food Pictures

Affect Grid (1989). Participants reported changes in mood

and arousal using the Affect Grid [24], which is a valid

and reliable self-report, single-item scale that assesses

two dimensions of affect states: mood (positive feelings

vs. negative feelings) and arousal (excitement vs sleepi-

ness or calmness). The scale is completed at two times

and the difference in ratings from Time 1 to Time 2 is re-

corded. Negative difference scores indicate a decrease in

mood/arousal; positive scores indicate an increase in

mood/arousal.

EDIS-S. The estimated daily intake scale for sugar

(EDIS-S [25]) is a valid and reliable 11-item scale to es-

timate daily intake of sugar in one’s diet. Participants in-

dicate their level of agreement to each item from 1 (com-

pletely disagree) to 7 (completely agree). Total scores

range from 11 to 77, with higher scores indicating greater

daily intake of sugar.

EDIS-F. The estimated daily intake scale for fat (EDIS-

F [26]) is a valid and reliable 13-item scale to estimate

daily intake of fat in one’s diet. Participants indicate their

level of agreement to each item from 1 (completely dis-

agree) to 7 (completely agree). Total scores range from

13 to 91, with higher scores indicating greater daily in-

take of fat.

Food pictures. Participants were shown four sets of

food image slideshows using Microsoft PowerPoint® soft-

ware with each slide image depicting a single food that

was automatically timed every 9 s to transition to a new

slide. A sample set of food pictures is given in Figure 1.

Each slideshow presentation had 15 food pictures for a

total of 135 s per slideshow. The four sets of food pic-

tures were foods that were high fat-high sugar (HFHS),

high fat-low sugar (HFLS), low fat-high sugar (LFHS),

or low fat-low sugar (LFLS). HFHS food images were

desserts, such as cakes, ice creams, and pies; HFLS foods

were fried foods, such as chicken wings, pizzas, and fries;

LFHS foods were fruits, such as apples, grapes, and or-

anges; LFLS foods were vegetables, such as carrots, peas,

and potatoes.

All food images were displayed on a plain background

and formatted to be the same size with no other identify-

ing features on the slide, other than the food itself. All

HFHS HFLS LFHS LFLS

Figure 1. A sample of two food pictures depicted in each of

four sets of slideshows for foods that varied in sugar and fat

content. A total of 15 food pictures were presented in color

in each food category.

G. J. PRIVITERA ET AL. 3

food images were chosen based on a separate pilot sam-

ple of 55 participants who rated the food images as ma-

tching in complexity, valence and arousal, same as crite-

ria used in prior food image studies [12].

2.3. General Procedures

Participants were observed between 3:00 PM and 4:00

PM in a classroom setting in small groups of five to ten

at a time. Participants were given and signed an informed

consent and instructed to orient toward the front of the

room at all times and not to speak to one another during

the study. All participants followed these instructions. As

an exercise to prime a neutral emotional state, partici-

pants were then asked to close their eyes and imagine a

place or situation that was neither positive nor negative.

After 10 s participants were asked to open their eyes and

to rate their current level of mood and arousal on the af-

fect grid. Participants were again told to orient their at-

tention toward the screen in front of them and the first of

four sets of food picture PowerPoint® slideshows were

displayed. After the slideshow ended participants were

asked to rate their post level of mood and arousal on the

affect grid. After 20 s to complete the affect grid, the

same procedures were repeated starting with the exercise

to prime a neutral emotional state until all four sets of

slideshows were presented and participant’s had rated

their pre-post measures on the affect grid for each slide-

show. Once all measures were recorded, participants

were debriefed, thanked for their time, and dismissed.

A Latin square procedure was used to counterbalance

the order of food picture displays such that the orders of

slideshows were: HFHS- > HFLS- > LFHS- > LFLS (n =

23), HFLS- > LFHS- > LFLS- > HFHS (n = 24), LFHS-

> LFLS- > HFHS- > HFLS (n = 24), LFLS- > HFHS- >

HFLS- > LFHS (n = 24). The order of slideshows were

counterbalanced such that each slideshow occurred equally

often in each ordered position and each slideshow pre-

ceded and followed the other slideshow one time.

2.4. Statistical Analysis

An analysis of covariance (ANCOVA) was computed

with Fat (high, low), and Sugar (high, low) as the within

subjects factors, and EDIS-F and EDIS-S scores included

as covariates. The dependent variables were mood and

arousal ratings. For significant effects, 95% confidence

intervals (CIs) were drawn. The null hypothesis under

evaluation for each group was that the difference score of

the population was zero. A significant change in mood

and arousal was identified if the CI did not envelop zero.

3. Results

No significant differences between groups were evident

for pretest scores of mood and arousal (p > 0.44 for both

measures in each group); hence, initial ratings on these

measures were statistically similar prior to the slideshows.

Effects of gender and BMI were also not significant be-

tween groups (p > 0.38 for both measures) and so both

factors were excluded from further analyses.

3.1. Mood Ratings

For mood ratings, a significant Fat × Sugar interaction

was evident, F(1,92) = 7.19, p < 0.01 (R2 = 0.07). As

shown in Figure 2, mood significantly increased after

viewing high fat, high sugar foods (95% CI 0.79, 1.38),

high sugar, low fat foods (95% CI 1.05, 1.62), high fat,

low sugar foods (95% CI 0.05, 0.83), but not after view-

ing low fat, low sugar foods (95% CI −0.26, 0.34). A

main effect of Fat was significant, F(1,92) = 13.69, p <

0.001 (R2 = 0.13), with larger increases in high fat vs.

low fat groups. A main effect of Sugar was significant,

F(1,92) = 6.09, p = 0.015 (R2 = 0.06), with larger in-

creases in mood in the high sugar vs low sugar groups.

All analyses reported were significant with EDIS-F and

EDIS-S scores included as covariates.

3.2. Arousal Ratings

For arousal ratings, no significant effects were evident

with EDIS-F and EDIS-S scores included as covariates;

this was also true when each covariate was included se-

parately. Using an analysis of variance (ANOVA), ex-

cluding EDIS-F and EDIS-S scores as covariates, a sig-

nificant Fat × Sugar interaction, F(1,94) = 21.68, p <

0.001 (R2 = 0.19), main effect of Fat, F(1,94) = 12.10, p

= 0.001 (R2 = 0.11), and main effect of Sugar, F(1,94) =

5.57, p = 0.02 (R2 = 0.06), were all evident. As shown in

Figure 3, arousal significantly increased after viewing

high fat, high sugar foods (95% CI 0.91, 1.50), high fat,

low sugar foods (95% CI 1.13, 1.84), high sugar, low fat

foods (95% CI 0.90, 1.53), but not after viewing low fat,

low sugar foods (95% CI −0.02, 0.61). Because all effects

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0.0

-0.2

Pre-Post Mood Ratings

High Sugar

Low Sugar

Low Fat

High FatGroups

Figure 2. Mean difference in mood ratings following slide-

shows for foods that vary in sugar and fat content. Results

show significant changes in mood in all groups, except

Group LFLS. Error bars indicate SEM .

G. J. PRIVITERA ET AL.

High Sugar

Low Sugar

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0.0

-0.2 High Fat Low Fat

Groups

Pre-Post Arousal Ratings

Figure 3. Mean difference in arousal ratings following

slideshows for foods that vary in sugar and fat content. Re-

sults show significant changes in arousal in all groups, ex-

cept Group LFLS, and these changes can be accounted for

by participant histories with sugar and fat content. Error

bars indicate SEM.

were not significant when EDIS-F and EDIS-S scores

were included as covariates, it appears likely that the

reported significant changes in arousal can be fully ex-

plained by the dietary histories of sugar and fat intake

among participants.

4. Discussion

The hypothesis that nutrient-specific manipulations of

high/low fat and sugar food images will influence emo-

tional responsiveness and that these changes may be re-

lated to dietary histories with fat and sugar intake was

tested. Results show that the presentation of high fat and

high sugar foods significantly enhanced mood, even for

high sugar foods (i.e., fruits) that were low calorie. Also,

the observed increase in mood in response to high fat,

high sugar food images was independent of a partici-

pant’s history with sugar and fat intake.

Because motivational salience is directly related to the

arousal of a stimulus or food cue [27,28], it was hypothe-

sized that arousal may be significantly enhanced follow-

ing the presentation of more desirable foods, i.e., foods

that induced greater motivational salience or wanting [23,

29]. While significant changes in arousal were observed

following the presentation of high fat and high sugar

foods, these changes were fully accounted for by a par-

ticipant’s dietary history with sugar and fat intake. The

finding that changes in arousal, but not mood, were de-

pendent on a participant’s history with sugar and fat in-

take may reflect recent data showing that the emotion-

and arousal-inducing properties of a cue or food cue are

processed in distinct areas of the brain, likely in the or-

bitofrontal cortex [28,30].

Another novel outcome is the finding that changes in

mood and arousal were statistical similar in all groups,

except Group LFLS (vegetables) showed no significant

change in mood or arousal. The increase in mood and

arousal observed in Groups HFHS (desserts) and HFLS

(fried foods) were fully predicted by neuroimaging stud-

ies showing greater activation of brain reward regions for

high vs. low calorie foods [10,12,14-15]. However, simi-

lar increases in mood and arousal were observed in

Group LFHS (fruits), which was a low calorie group of

foods that taste sweet. In this study, then, the pattern of

results suggests that categories of foods as being low vs.

high calorie may be too broad in that behavioral evidence

for increases in intakes [23] and enhancement of mood

and arousal (shown here) is observed for low calorie

foods that taste sweet—likely because sweet tastes stimu-

late brain reward regions [29,31], enhance food intake

[32], and increase reported liking/pleasantness of foods

even when the caloric content is negligible [5,25,33].

5. Conclusion

In all, these data extend prior neuroimaging and behav-

ioral data by showing that solely viewing images of high

fat, high sugar foods will enhance mood and arousal,

even for foods that taste sweet but are low calorie, with

changes in arousal being dependent on a participant’s

history with sugar and fat intake. Only when vegetables

(i.e., LFLS) were depicted were changes in mood and

arousal not observed. All participants were hungry at the

time of the study to control for hunger states. While some

studies show that women, but not men, are less respon-

sive to food pictures when sated [12,16], the present study

does show that when hungry, men and women have

similar increases in mood and arousal following pictures

with high sugar or high fat, but not LFLS foods. There-

fore, changes in emotional responsiveness to food images

are nutrient-specific, and an increase in mood, but not

arousal, occurs independent of participant dietary histo-

ries.

6. Acknowledgements

This research was partly supported by an internally fun-

ded Faculty Research Grant awarded to the first author.

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