Many eating-related psychological constructs have been proposed to explain obesity and over-eating. However, these constructs, including food addiction, disinhibition, hedonic hunger, emotional eating, binge eating, and the like all have similar definitions, emphasising loss of control over intake. As questionnaires measuring the constructs correlate strongly (r>0.5) with each other, we propose that these constructs should be reconsidered to be part of a single broad phenotype: Uncontrolled Eating (UE). Such an approach enables reviewing and meta-analysing evidence obtained with each individual questionnaire. Here, we describe robust associations between UE, body mass index (BMI), food intake, psychological traits, and brain systems. Reviewing cross-sectional and longitudinal data, we show that UE is phenotypically and genetically intertwined with BMI and food intake. We also review evidence on how three independent psychological constructs may contribute to UE: heightened food reward sensitivity, lower self-control, and higher negative affect. UE mediates all three constructs associations with BMI and food intake. Finally, we review and meta-analyse brain systems subserving UE: namely, (i) the dopamine mesolimbic circuit associated with reward sensitivity, (ii) frontal cognitive networks sustaining dietary self-control, and (iii) the hypothalamus-pituitary-adrenal axis, amygdala and hippocampus supporting stress reactivity. While there are limits to the explanatory and predictive power of the UE phenotype, we conclude that treating different eating-related constructs as a single concept, UE, enables drawing robust conclusions on the relationship between food intake and BMI, psychological variables, and brain structure and function.
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