Background: Binge eating is a marker of weight gain and obesity, and a hallmark feature of eating disorders. Yet its component constructs - overeating and loss of control (LOC) while eating - are poorly understood and difficult to measure. Objective: The objective of this study is to critically review the human literature concerning the validity of LOC and overeating across the age and weight spectrum. Data sources: English-language articles addressing the face, convergent, discriminant and predictive validity of LOC and overeating were included. Results: Loss of control and overeating appear to have adequate face validity. Emerging evidence supports the convergent and predictive validity of the LOC construct, given its unique cross-sectional and prospective associations with numerous anthropometric, psychosocial and eating behaviour-related factors. Overeating may be best conceptualized as a marker of excess weight status. Limitations: Binge eating constructs, particularly in the context of subjectively large episodes, are challenging to measure reliably. Few studies addressed overeating in the absence of LOC, thereby limiting conclusions about the validity of the overeating construct independent of LOC. Additional studies addressing the discriminant validity of both constructs are warranted. Discussion: Suggestions for future weight-related research and for appropriately defining binge eating in the eating disorders diagnostic scheme are presented.