Search

The current study used a modified implicit association test (IAT) to change implicit evaluations of unhealthy snack food and tested its effects on subsequent consumption. Furthermore, we investigated whether these effects were moderated by inhibitory self-control. A sample of 148 women (17–25 years) motivated to manage weight through healthy eating completed an IAT intervention, and pre- and post-intervention IATs assessing implicit evaluations of unhealthy food. The intervention IAT trained participants to pair unhealthy food stimuli with either positive or negative stimuli. A task disguised as a taste-test was used to assess consumption of unhealthy snack foods. Inhibitory self-control was measured using a self-report scale. As predicted, the implicit evaluation of unhealthy food became more negative from pre- to post-training among participants in the food negative pairing condition; however, there was no corresponding change in the food positive pairing condition. The effect of the training on snack consumption was moderated by inhibitory self-control with only participants low in inhibitory self-control having lower snack intake following the food negative training. This finding is consistent with dual-process models of behaviour which predict that self-control capacity renders impulses less influential on behaviour. Furthermore, it suggests that an intervention that retrains implicit food evaluations could be effective at reducing unhealthy eating, particularly among those with low inhibitory self-control. [ABSTRACT FROM AUTHOR]

Portion size impacts on the amount of energy consumed during a meal. However, research findings on participant characteristics that moderate the effect of portion size on energy intake are mixed. Using data pooled across three randomized control trials, we examined the impact of reducing meal portion size on meal energy intake in 111 adult participants varying in sex (55 M, 56 F), body weight (BMI range = 19-42) and a broad range of participant characteristics, including usual portion size, restrained, emotional and external eating, satiety responsiveness, plate clearing tendencies, concerns about wasting food and self-control. In each trial, a repeated-measures design was used and participants consumed three ad-libitum lunchtime meals differing in portion size; large-normal portion size condition (100%) vs. small-normal portion size condition (~ 75%) vs. smaller than normal portion size condition (~ 50%). In mixed ANOVAs, we did not find convincing evidence that any participant characteristic reliably moderated the impact that reducing portion size had on energy intake. For the majority of participants energy intake decreased when portion size was reduced and it was more common for participants to consistently reduce their energy intake than consume a similar amount when portion size was reduced. We also found little evidence that a sub-group of participants existed whose energy intake was consistently resistant to portion size reductions. Portion size may be a universal driver of energy intake, as reducing meal portion size appears to decrease meal energy intake among most people. Food portion downsizing may therefore be an equitable intervention approach to reducing population level energy intake. [ABSTRACT FROM AUTHOR]

Research conducted in controlled laboratory settings plays an important role in understanding human eating behaviour. However, participant characteristics may affect motivation to participate in laboratory eating behaviour research and result in self-selection biases. First-year psychology students (n = 207, 90.8% female, m age = 18.8, m BMI = 21.9) were led to believe that they were choosing between enrolling in one of two laboratory-based studies: an 'advertising' study, or an 'advertising and food' study; the latter specified that participants would consume food and answer questions about their eating behaviour. Participants subsequently reported demographic information and completed a series of questionnaires assessing psychological characteristics hypothesised to predict self-selection in laboratory eating studies. The majority of participants preferred to participate in a study unrelated to eating over an eating-related study (70.5%, χ2 (1) = 34.90, p < .001). Participants choosing the eating-related study over the non-eating study had higher self-reported external eating tendencies and positive preoccupations with food, lower negative preoccupations with food and social appearance anxiety. Participants choosing the eating related study were also more likely to be male than female, although the number of males in the study was small (n = 19) and this finding should therefore be interpreted with caution. The present study provides some evidence that in university based samples of participants there are likely self-selection biases in laboratory-based eating behaviour studies and researchers may benefit from considering the potential influence of self-selection biases when conducting eating behaviour research. [ABSTRACT FROM AUTHOR]