Summary Obesity is considered a public health crisis. In order to tackle this, an enhanced appreciation of what drives some consumers to overeat is required. It is clear that several features of the modern environment encourage over-consumption in many people, at least some of the time. However, there is variation in the extent to which this translates into weight gain. Understanding whether susceptibility is dispositional or learned will shape prevention and treatment programmes. This review identifies situational cues that promote overeating and dispositional traits, such as impulsivity and sensitivity to reward, which make some individuals specifically vulnerable to overeating. These traits are likely to contribute to the development of the obese state, but also present barriers to weight management. Personalised nutrition and behavioural strategies may provide a novel and innovative approach, as these take account of individual differences in vulnerability to overeating.