Biobehavioral Mechanisms Underlying Non-homeostatic Eating

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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.