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Abstracts / Appetite 55 (2010) 164–174
soft sweets (ns). Interestingly, OPT of the fixed amounts and ad libitum intake of the first 6 sessions were significantly negatively correlated (r = −0.38; p < 0.05). In conclusion, texture differences within the pairs of products may have been too small to bring about differences in ad libitum intake. Further attention should be paid to the relationship between OPT and ad libitum intake of solid foods. doi:10.1016/j.appet.2010.05.069
In a second experiment, a flavour was paired with 20 min running exercise across two trials and this procedure failed to induce a flavour aversion, despite the fact that the 20 min running bout did induce some nausea. We tentatively conclude that exerciseinduced flavour aversions can be established in humans but that it requires intense exercise and that discomfort may not be a prerequisite for exercise-induced flavour aversions. doi:10.1016/j.appet.2010.05.071
Variety seeking behaviour and sensory specific satiety LAURA L. WILKINSON ∗ , JEFFREY M. BRUNSTROM Dept. of Experimental Psychology, University of Bristol, 12a Priory Road, Bristol BS8 1TU, UK
Eating rate and viscosity in learned satiation PLEUNIE HOGENKAMP 1,2,∗ , ANNETTE STAFLEU 1,3 , MONICA MARS 1,2 , CEES DE GRAAF 1,2 1 Top Institute Food and Nutrition, 2 Division of Human Nutrition, Wageningen, The Netherlands Wageningen University, Wageningen, The Netherlands 3 TNO Quality of Life, Zeist, The Netherlands
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[email protected] (L.L. Wilkinson). Exploratory behaviour is a primary reinforcer in animals and humans. In humans, ‘variety seeking’ is evident in numerous contexts including purchasing behaviour. During product selection, variety increases consumers’ satisfaction. Additionally, the mere knowledge of another (unavailable) set of products tends to decrease satisfaction with a selected product. Parallels can be drawn between these findings and the literature on sensory specific satiety (SSS). Studies of SSS involve participants rating a set of taster foods and then eating one of these foods (determined by the experimenter) until satiated. The taster foods can be regarded as ‘unavailable variety’; this may help to promote the decrease in pleasantness of the eaten food. This idea was explored by comparing perceived pleasantness in a ‘no variety’ (eaten food presented alone), ‘unavailable variety’ and ‘available variety’ (allowed to switch to a ‘taster’ food) condition. Participants’ (N = 60) ratings of food pleasantness and ‘desire to eat’ were assessed at baseline, during (2 min) and after the meal. Consistent with the SSS literature, a decrease in desire to eat and pleasantness of the eaten food was observed across conditions. However, the decrease in ratings was larger in the unavailable variety condition. Although the pattern of results shows the hypothesised trend, this difference failed to reach significance. This may be because the verbal command given to indicate whether variety was available or unavailable may not have been potent enough. This prospect merits further investigation as it challenges our basic understanding of SSS. doi:10.1016/j.appet.2010.05.070 Exercise-induced flavour aversion learning in humans REMCO C. HAVERMANS ∗ , THOMAS HEIJENS, ASTRID FRANKORT, ANITA JANSEN Maastricht University, Dept Clinical Psychological Science, Faculty of Psychology & Neuroscience, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands E-mail address:
[email protected] (R.C. Havermans). When a flavour is paired with an illness-inducing agent, the flavour becomes disliked. This flavour aversion learning is an extensively investigated form of Pavlovian conditioning and has been demonstrated in both animals and humans. Conditioned flavour aversions are thought to require the experience of some degree of illness or discomfort. However, relatively recent research shows that rats also develop a conditioned flavour aversion when the flavour is paired with physical exercise. Although exercise can induce discomfort, exercise-induced flavour aversions do not appear to rely on the experience of such discomfort. We investigated whether exercise can also induce conditioned flavour aversions in humans and if so, to what degree exercise-induced discomfort (i.e. nausea) plays a role. In a first experiment, a flavour was paired with 30 min running exercise in a single trial and it was found that this led to a decrease in subjective liking for the flavour irrespective of any experienced discomfort during running.
Higher viscosity and lower eating rates lead to an increased sensory stimulation. It is hypothesized that a high sensory exposure to a food enhances the learned association between sensory signals and their metabolic consequences (“learned satiation”). In three intervention groups, subjects consumed low viscosity (LV) yogurt with a straw (LV/straw; n = 34); the same LV yogurt with a spoon (LV/spoon; n = 36); or high viscosity (HV) yogurt with a spoon (HV/spoon; n = 35). Over a period of 4 weeks, novel flavoured yogurts were offered ad libitum for breakfast in a high energy (HE) dense (150 kcal/100 g) or low energy (LE) dense (50 kcal/100 g) version. Subjects were exposed 10 times to each yogurt on alternate days, and intake levels (g) were measured. Average consumption over 10 exposures was 575 ± 260 g, 475 ± 192 g and 470 ± 223 g; eating rates were 154 g/min; 98 g/min and 99 g/min in the LV/straw, LV/spoon and HV/spoon intervention groups, respectively. Intake of LE yogurts was higher than of HE yogurts when corrected for pleasantness (F(1,1595) = 27.03; p < .0001). No significant interactions effects on intake between mode of eating, energy density and exposure time were observed, and intake levels of the two energy levels did not change over exposure time in any of the intervention groups (exposure time × energy: F(8,1603) = 1.19; p = 0.30). These results did not show energy intake compensation; nor was there evidence of any learned associations between the flavour of the food and its post-ingestive consequences. The differences in ad libitum intake of yogurt can be explained by differences in eating rate. doi:10.1016/j.appet.2010.05.072 Glucose facilitation of visual memory LAURA STOBBS, COLIN HAMILTON, ELIZABETH ORME, JONATHON REAY ∗ School of Psychology and Sport Sciences, Northumbria University, Newcastle upon Tyne NE1, UK E-mail address:
[email protected] (J. Reay). The human brain is somewhat dependent upon the constant and uninterrupted delivery of blood borne energy substrates (i.e. glucose) and as a result numerous reports have shown the susceptibility of the human brain and consequently cognitive functioning to subtle changes in circulating blood glucose levels. For example, impaired functioning has been associated with reductions in circulating blood glucose levels whereas enhanced functioning has been reported following a glucose drink, in young healthy volunteers; however, these reports are by no means unequivocal. The precise mechanism by which glucose modulates cognitive performance is still unclear, as too are the conditions that are needed to evoke a glucose facilitation effect. The present single blind, placebo-controlled study aimed to investigate visual memory’s susceptibility to changes in blood glucose levels; particularly investigating any differential impact upon the “process” or “mnemonic”