Biomedical subjects

Gemma L Mitchell

Publications and source records attributed to Gemma L Mitchell.

5 recordsLinked to original sources

PubMed2006

Flavor-nutrient learning in restrained and unrestrained eaters.

After we consume a novel food an association can form between its sensory characteristics (e.g., taste properties) and the effect it has on the body (rewarding). Associations of this kind underpin much of our everyday dietary behavior because they mediate both the affective quality of food (flavor-preference learning) and the amount that we choose to consume (learning satiation). Notwithstanding this fact, very few studies have successfully demonstrated the process of dietary learning in human adults. In addition, based on evidence from related research, we explored whether learning is less likely to occur in individuals who have high scores on a measure of dietary restraint. Female participants (N = 44) consumed two differently flavored desserts. Each was presented three times on separate days. One was formulated with a high-energy content (1882 kJ) and the other with a low-energy content (226 kJ). After training, we found little evidence for learned satiation. However, we did observe flavor-preference learning. Specifically, participants acquired a greater liking and desire-to-eat the dessert flavor that was paired with a higher energy density during training. Further analysis revealed that this effect on liking is qualified by dietary restraint. As predicted, unrestrained eaters demonstrated greater differential responding to the two desserts than did restrained eaters. These data provide further evidence for flavor-nutrient learning in adults and they highlight a hitherto unexplored and potentially important difference between restrained and unrestrained eaters.

Adolescent↗

PubMed2006

Effects of distraction on the development of satiety.

Two experiments explored the hypothesis that distraction causes a reduced sensitivity to the physiological and sensory cues that signal when to terminate a meal. In Experiment 1, eighty-eight females ate five 'Jaffa Cakes' either while distracted by a computer game or while sitting in silence. Analysis of the difference in rated hunger, fullness and desire to eat (pre- to post-intake) revealed that distracted participants experienced smaller changes in their desire to eat and fullness than did non-distracted participants. Experiment 2 assessed whether changes in ratings are attenuated because sensory-specific satiety (or a related process) fails to develop. Using a similar procedure, eighty-four females provided desire to eat, pleasantness and intensity ratings for Jaffa Cakes and for two 'uneaten' foods, both before and at three time-points after consuming five Jaffa Cakes. Non-distracted participants reported a reduction in their desire to eat the eaten food relative to the uneaten food (food-specific satiety), whereas distracted participants maintained a desire to eat all foods. Moreover, this difference between distracted and non-distracted participants was evident 5 and 10 min after the eating episode had terminated. The present findings invite speculation that distraction attenuates the development of sensory-specific satiety, and that this effect persists (at least for a brief period) after the distractor has terminated. More generally, this kind of phenomenon warrants further scrutiny because it holds the potential to contribute towards overeating, either by prolonging an eating episode or by reducing the interval between meals.

Adolescent↗

PubMed2005

Dietary restraint and cognitive performance in children.

Adults who attempt to restrict their dietary intake also tend to perform worse on a range of cognitive tasks. However, the extent to which this finding generalises to children has remained unclear. Following studies involving adults, we asked 44 girls (mean age = 10.1 years) to complete a simple reaction-time task and the Tower of London task. This group was selected from a local community school in the East Midlands (UK). Dietary restraint was measured using a version of the Dutch Eating Behaviour Questionnaire that had been adapted for use by children. Our results indicate that children with high restraint scores have longer reaction times and they also tend to perform worse on the TOL task. Other aspects of our data also suggest the dietary restraint may be correlated negatively with a measure of academic ability. We discuss reasons why restraint and performance might be related causally and we conclude that this issue warrants further scrutiny.

Child↗

PubMed2005

Dietary restraint and US devaluation predict evaluative learning.

Previous research has indicated that flavor-flavor learning is impaired in restrained eaters. In Experiment 1 we sought to extend this finding using a larger sample and a more comprehensive assessment of dietary behavior. Participants (N=90, including 30 current dieters) sampled three novel flavors (CSs), each on 10 separate occasions, in a randomized order. Each flavor was paired with chocolate (US) either 10%, 50%, or 90% of the time. We then assessed liking for the three CSs and asked participants to complete the DEBQ-restraint and TFEQ-disinhibition sub-scales. After these CS-US parings, restrained eaters tended to prefer the 10% paired flavor whereas unrestrained eaters tended to prefer the 90% paired flavor. Differential CS liking was not evident in dieters and it was not predicted by disinhibition. Using a similar methodology, in Experiment 2 (N=76) we assessed evaluative change following picture-sweet pairings. Relative to the other CSs, the restrained eaters reported a greater increase in their liking for the 10% paired CS and the unrestrained eaters reported a greater increase in their liking for the 90% paired CS. We also discovered that evaluative change is related to the level of US devaluation that takes place during conditioning. Evidence that a sweet US can bring about a decrease in liking has not been reported previously. One interpretation is that negative beliefs and attitudes can contaminate the representation of the US during training.

Adult↗

PubMed2005

Everyday dietary behaviour and the relationship between attention and meal size.

Previously, it has been demonstrated that overeating can occur when an individual engages in a cognitive task during a meal. One possibility, therefore, is that task performance can provide a measure of attention to dietary control. To explore this idea we measured performance on an otherwise irrelevant task during a meal. In two experiments, we compared intake and performance across five groups of females; dieters, and four groups of non-dieters, each with contrasting high and low scores on the restraint scale of the Dutch Eating Behaviour Questionnaire and the disinhibition scale of the Three-Factor Eating Questionnaire. Our analysis suggests that a correspondence can exist between task performance and intake (Experiment 1) and this might be influenced by the extent to which foods are regarded as forbidden (Experiment 2). However, aspects of our data are difficult to reconcile with the idea that task performance reflects a simple measure of attention to dietary control. Instead, one possibility is that individuals differ in the way that they choose to allocate attention during a meal. In relation to this idea, we discuss the possibility that some individuals choose to avoid food-related cognition by engaging strategically with other aspects of their cognitive environment.

Adult↗