Out-of-home foods (takeaway, take-out and fast foods) have become increasingly popular in recent decades and are thought to be a key driver in increasing levels of overweight and obesity due to their unfavourable nutritional content. Individual food choices and eating behaviours are influenced by many interrelated factors which affect the results of nutrition-related public health interventions. While the majority of research based on out-of-home foods comes from Australia, the UK and USA, the same issues (poor dietary habits and increased prevalence of non-communicable disease) are of equal concern for urban centres in developing economies undergoing ‘nutrition transition’ at a global scale. The present narrative review documents key facets, which may influence out-of-home food consumption, drawn from biological, societal, environmental, demographic and psychological spheres. Literature searches were performed and references from relevant papers were used to find supplementary studies. Findings suggest that the strongest determinants of out-of-home food availability are density of food outlets and deprivation within the built environment; however, the association between socio-economic status and out-of-home food consumption has been challenged. In addition, the biological and psychological drives combined with a culture where overweight and obesity are becoming the norm makes it ‘fashionable’ to consume out-of-home food. Other factors, including age group, ethnicity and gender demonstrate contrasting effects and a lack of consensus. It is concluded that further consideration of the determinants of out-of-home food consumption within specific populations is crucial to inform the development of targeted interventions to reduce the impact of out-of-home foods on public health.