Biobehavioral Mechanisms Underlying Non-homeostatic Eating

鉴于在我们的环境中非常可口的食物的流行和可获得性，人类经常在没有任何生理需要的情况下进食。事实上，我们大多数人都能回忆起我们在刚吃完一顿饱饭后选择甜点的时候，或者我们在考试时吃了一袋薯条的时候。除了饥饿之外，根据其他线索进食被广泛称为“非稳态进食”，这种行为与加拿大和世界上许多地方的肥胖率上升有关。 非稳态饮食的研究集中在解释谁最有可能参与这些饮食模式的个体差异上;然而，很少有人解决与何时，为什么以及如何发生这种行为有关的具体问题。尽管有令人信服的理论，奖励和控制相关的神经回路在驱动非稳态饮食中的作用，但在人类中测试这些模型的直接证据有限。特别是，许多评估享乐饮食的研究（即，为娱乐而吃）测量短期限食后的食物摄入量。这种方法限制了我们完全区分调节稳态与非稳态饮食的机制的能力。因此，这项研究计划的总体目标是更好地表征导致人类非稳态饮食的神经生物学机制。这些目标将通过一系列研究来实现，这些研究涉及几个不同但相关的研究问题。项目1将评估非稳态饮食及其生物行为相关性的结构效度和多方面。项目2将直接评估特定大脑区域的作用（即，背外侧前额叶皮层）在调节进食动机和在没有饥饿的情况下进食。我们所有的研究都将包括男性和女性，以增加研究结果的普遍性，并对非稳态饮食中潜在的性别和性别差异进行探索性分析。

Given the prevalence and accessibility of highly palatable foods in our environment, humans often eat in the absence of any physiological need for food. Indeed, the majority of us can recall times when we opted for dessert despite being full from the meal we just consumed, or times when we ate a bag of chips while studying for an exam. Eating in response to cues other than hunger is broadly referred to as "non-homeostatic eating," and this behaviour has been implicated in the rise of obesity across Canada and much of the world.  Studies of non-homeostatic eating have focused on individual differences that explain who is most likely to engage in these eating patterns; however, few have addressed specific questions related to when, why, and how this behaviour occurs. Despite compelling theories for the role of reward- and control-related neural circuitry in driving non-homeostatic eating, there is limited direct evidence testing these models in humans. In particular, much research assessing hedonic eating (i.e., eating for pleasure) measures food intake after short-periods of food restriction. This approach limits our ability to fully differentiate mechanisms that regulate homeostatic versus non-homeostatic eating. Thus, the overarching goals of this research program are to better characterize the neurobiological mechanisms that contribute to non-homeostatic eating in humans. These goals will be accomplished through a series of studies that address several distinct but related research questions. Project 1 will evaluate the construct validity and multidimensional aspects of non-homeostatic eating and their biobehavioural correlates. Project 2 will directly assess the role of specific brain regions (i.e., dorsolateral prefrontal cortex) in regulating motivation to eat and eating in the absence of hunger. All of our studies will include both men and women in order to increase the generalizability of findings and to conduct exploratory analyses of potential sex and gender differences in non-homeostatic eating.