Department of Psychology, Bucknell University, Lewisburg, PA, USA.
School of Psychological Science, University of Bristol, Bristol, UK; National Institute for Health Research Bristol Biomedical Research Centre, University Hospitals Bristol NHS Foundation Trust and University of Bristol, UK.
Appetite. 2019 Feb 1;133:212-216. doi: 10.1016/j.appet.2018.11.007. Epub 2018 Nov 14.
For people in the modernized food environment, external factors like food variety, palatability, and ubiquitous learned cues for food availability can overcome internal, homeostatic signals to promote excess intake. Portion size is one such external cue; people typically consume more when served more, often without awareness. Though susceptibility to external cues may be attributed to the modernized, cue-saturated environment, there is little research on people living outside that context, or with distinctly different food norms. We studied a sample of Samburu people in rural Kenya who maintain a traditional, semi-nomadic pastoralist lifestyle, eat a very limited diet, and face chronic food insecurity. Participants (12 male, 12 female, aged 20-74, mean BMI = 18.4) attended the study on two days and were provided in counterbalanced order an individual serving bowl containing 1.4 or 2.3 kg of a familiar bean and maize stew. Amount consumed was recorded along with post-meal questions in their dialect about their awareness of intake amount. Data were omitted from two participants who consumed the entire portion in a session. Even though the 'smaller' serving was a very large meal, participants consumed 40% more when given the larger serving, despite being unable to reliably identify which day they consumed more food. This result in the Samburu demonstrates the portion size effect is not a by-product of the modern food environment and may represent a more fundamental feature of human dietary psychology.
对于生活在现代化食品环境中的人来说，食物种类、口感和无处不在的食物可获得性学习提示等外部因素可以克服内部的稳态信号，促进过量摄入。份量大小就是这样的一个外部提示；人们通常会在提供更多份量时吃得更多，而且常常没有意识到这一点。尽管易受外部提示的影响可能归因于现代化、提示饱和的环境，但对于生活在这种环境之外的人或具有明显不同的食物规范的人，研究甚少。我们研究了肯尼亚农村的桑布鲁人样本，他们保持着传统的半游牧牧民生活方式，饮食非常有限，面临着长期的粮食不安全。参与者（12 名男性，12 名女性，年龄 20-74 岁，平均 BMI=18.4）在两天内参加了这项研究，并以平衡的方式提供了一个单独的装食物碗，碗中装有 1.4 或 2.3 公斤熟悉的豆和玉米炖菜。记录了他们食用的量，并在他们的方言中询问了用餐后的问题，了解他们对摄入量的意识。有两名参与者在一次用餐中就吃完了整份食物，因此数据被省略。尽管“较小”的份量是一顿非常大的餐，但参与者在提供较大份量时会多食用 40%，尽管他们无法可靠地识别出他们在哪一天吃了更多的食物。桑布鲁人的这一结果表明，份量大小的影响不是现代食品环境的副产品，可能代表了人类饮食心理学的一个更基本特征。
