The consumption of energy-dense fast foods has been implicated as a causal factor in the development of obesity. The development of strategies to modify food choice behaviour requires an understanding of the behaviour and the driving factors. This study examined the rationale behind decisions to either choose or avoid fast foods. Drawing partly on the Theory of Planned Behaviour (Ajzen, (1988)), a qualitative design was employed to examine the beliefs and perceptions associated with fast-food consumption within an Australian sample. Findings provided an indication that positive affective reactions to fast food, convenience, and self-serving cognitions may override cognitive analyses of the longer-term health risks associated with frequent fast-food consumption.