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; participant 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 images. Also,
participant histories with sugar and fat should be taken into account as these
histories can explain the changes in arousal observed here.