Understanding decisions about portion size: The key to acceptable foods that reduce energy intake?

长期以来，研究人员一直对开发既能填饱肚子又低热量的美味食物感兴趣。在几乎所有的研究中，关键的依赖指标都是“吃了多少”，或者在吃完特定的测试食物后对饥饿感和饱腹感的其他评估。这里的逻辑是，食量通常是由进食过程中和即将结束时的心理和生理影响决定的。这个项目将1)挑战这一基本假设，2)展示对份量决定的理解如何帮助我们识别促进低能量摄入的美味食物。该项目的第一阶段将寻找证据，证明在我们可以控制饭量的情况下（我们怀疑这种情况经常发生），决定食物摄入量的最重要因素是饭前选择多少的决策。在这样做的过程中，我们的目标是提供1)证据，证明“传统”方法并不适合开发减少能量摄入的食物，以及2)为一种新的方法提出关于食物特征及其对份量决定的影响的理由。在确定了份额大小决定的重要性之后，第二阶段将探索做出份额大小决定的基础。将特别强调对测试食品的喜爱程度和对它们的饱腹感的期望的相对重要性，重点关注这些因素如何在消费者心中结合起来。通过这样做，我们将能够提出可能有助于减少能量摄入的特定食物，并且我们将提供可用于探索未来许多其他食物的新方法。最后，需要指出的是，我们并不是说饮食的生理效应对能量摄入的影响很小或没有作用，只是说它们的作用次于每顿饭的份量决定。从长远来看，这种生理反馈可能非常重要。事实上，我们怀疑分量大小的决定，在某种程度上，是从以前不同食物的饱腹效果的经验中学到的。该项目的最后阶段（第三阶段）将检验这一命题。这项研究将有助于我们理解食物份量决定的起源。这或许可以解释低能量“减肥食品”为消费者所熟悉后，在接受度和使用上可能发生的变化，它将突出“保护”防止接受度随着时间的推移而下降的方法。

Researchers have long been interested in the prospect of developing enjoyable foods that are filling yet low in calories. In almost all studies the critical dependent measure has been 'amount eaten' or some other assessment of feelings of hunger and fullness after a particular test food has been consumed. The logic here is that the amount eaten is normally determined by psychological and physiological effects of eating that take place during and towards the end of a meal. This project will 1) challenge this fundamental assumption and 2) show how an understanding of portion-size decisions can help us to identify palatable foods that promote lower energy intake. The first phase of this project will seek evidence that on occasions when we have control over meal size (which we suspect is very often), the most important determinant of food intake is the decision-making that underlies how much is chosen before a meal begins. In so doing, we aim to provide 1) evidence that 'traditional' methods are not best placed to develop foods that reduce energy intake, and 2) a justification for a new approach for asking questions about food characteristics and their effect on decisions about portion size. After establishing the importance of portion-size decisions, phase two will explore the basis on which decisions about portion-sizes are made. Particular emphasis will be placed on modelling the relative importance of liking for the test foods and expectations about how filling they are, focusing on how these factors combine in the mind of a consumer. In so doing, we will be able to propose particular foods that may help to reduce energy intake, and we will deliver new methods that can be used to explore many other foods in future. Finally, it is important to say that we are not proposing that physiological effects of eating play little or no role in influencing energy intake, merely that their role is secondary to portion-size decisions during individual meals. In the longer term, physiological feedback of this kind could be very important. Indeed, we suspect that portion-size decisions are, in part, learned from previous experiences of the filling effects of different foods. The final phase (phase 3) of this project will test this proposition. This research will inform our understanding of the origin of portion-size decisions. This may explain changes that can occur in the acceptability and use of low-energy 'diet foods' after they become familiar to a consumer, and it will highlight ways of 'protecting' against a decrease in acceptability over time.