Obesity has been described by the World Health Organisation as a global epidemic, and is perceived as a major health concern due to the associated medical, psychosocial, and economic problems. One approach of understanding obesity is directed towards exploring the psychological and social determinants underlying nonhungry eating (NHE) (eating without physical sensations associated with hunger) and overeating (eating past the physiological sensations of fullness). The immediate psychosocial cues that trigger NHE and overeating, along with the psychosocial antecedents that influence NHE and overeating have been found to be important contributors to obesity.This research incorporated two studies. Study 1 involved self-report questionnaires comparing the antecedents and cues that influence NHE and overeating among men and women who were obese, overweight, and of a healthy weight (HWR). Study 2 adopted a case study approach to explore individual antecedents and triggers of NHE and overeating among three obese participants.Findings indicated that HWR, overweight, and obese people differed in the antecedents and cues that influenced their eating behaviours, which were particularly borne out in quantitative data. In addition, females and males differed in their reported antecedents and cues. For example, across all three weight groups, more females than males were restricting their food intake in attempt to lose weight, which can result in future NHE and overeating. In addition, overweight females reported the highest levels of non-hungry eating, emotional eating and external eating, compared to all other groups. Males of a healthy weight reported the lowest amounts of both NHE and restrained eating of the six groups (crossing 2 x gender and 3 x weight groups).Interestingly, eating in response to external cues was least common in overweight ii males. Compared to the other weight groups, more overweight participants reported they ate quickly and at predetermined times, and that food had been used as a reward or to soothe pain throughout childhood. Overweight participants ate more frequently in response to positive emotions and experienced more negative emotions after overeating than healthy weight or obese participants.Although distinct patterns of eating behaviour were observed for males and females within the separate weight categories, variability was also evident within the groups, suggesting that despite having similar body mass indexes, antecedents and cues that maintain individuals' weights vary.Results of the qualitative study also highlight the diverse cues and antecedents that can contribute to an individual becoming and maintaining an obese weight. What is clear from both studies is that no one eating pattern typifies a particular weight group, in the case of healthy, overweight, or obese individuals. In addition, people who are overweight need to become a priority for obesity research, in order to increase the understanding of the psychology of why and how people transgress from an overweight to an ob...