用5个简短的英文句子分别概括一下五段To our knowledge, this is the first study to compare individual estimates of amounts of served food with the actual weight of the food served in a laboratory setting, where less disruptive data collection techniques are applied. Other studies assessing the accuracy of estimated portion sizes have used photographs as the reference for the assessment (Huybregts et al, 2007, Turconi et al, 2005), fake food items (Bucher et al, 2011, Bucher et al, 2012, Bucher et al, 2013) or average portion size weights based on repeated measures (Ngigi, Verbeke, & Pérez-Cueto, 2011). In contrast, the present study was performed using actual food items. In addition, the use of the Intelligent Buffet allowed the exact weight of food served by each participant to be recorded in a relatively undisturbed manner.

There are a few potential sources of bias in this study, one being measurement bias. An attempt was made to limit this by calibrating the equipment used for data collection before use and by following standard laboratory procedures. Therefore, if any measurement bias were to occur, it would be systematic throughout all observations. Secondly, the sample size may have been insufficient. However, the calculated power of 0.99 for the observed mean differences of both vegetables and whole grains suggests that the sample was enough to support the rejection of the null hypothesis. Previous studies have used a similar sample size with sufficient power (Mekhmoukh, Chapelot, & Bellisle, 2012). Thus, we assume that the result of the Wilcoxon signed-rank test was accurate (absence of type II error), and that it was correct to reject the null hypothesis since there was a significant difference between the two variables – the estimated and actual amount of food served.

Our findings are in agreement with similar studies conducted in a number of different countries and settings, including Norway (Uglem et al., 2008), the Netherlands (Lechner et al., 1997), Australia (Pollard et al., 2008) and Denmark (Sørensen et al., 2013), suggesting that individuals commonly have difficulties estimating food portion sizes with accuracy. The findings of a statistically significant difference between participants’ self-estimation and the actual weight of the vegetables served led to the rejection of the null hypothesis (Table 1). The participants in this study were also asked to estimate the weight of a whole grain serving in a relatively complex meal. It would be of interest to determine whether the results would have been more accurate if a simpler meal had been served (e.g. a bowl of cereal). However, the everyday diet commonly consists of prepared meals or ready-to-eat foods and individuals are often not aware of the actual composition of the foods they consume. Therefore, serving a “complex meal” is comparable with a real life situation, where participants are expected to estimate the amount of food served (Combet et al, 2013, Loh et al, 2013).

This study presents the question of whether food intake estimations that are independent of actual weighing are valid, particularly in the evaluation of adherence to healthy eating recommendations (Pérez-Cueto et al., 2012). This also underscores the importance of using alternative equipment and techniques, such as an Intelligent Buffet, in order to obtain actual data in studies measuring factors such as food intake (Bucher et al., 2012). The Intelligent Buffet presents many opportunities to conduct other studies or further research on this particular topic. In combination with video cameras, this equipment could be used for choice architectural experiments researching behaviour related to a buffet setting. For example, it could be used to investigate whether individual consumption differs in relation to the order of food items or the size of serving trays.