This article discusses the value of conducting participant observation in obesity research with children in an Australian community setting. Obesity is highly stigmatized, and the use of activity-based interviews exposed the intellectual and embodied consciousness that children negotiate when they take part in research about food and bodies. Instead of opening up possibilities, interview-based activities can lead to a moral correctness about healthy lifestyles. It was through participant observation, in engagement with what Deleuze and Guattari [1988. A Thousand Plateaus: Capitalism and Schizophrenia. London: Athlone Press] call striated and smooth (or regulated and unregulated) spaces of children's everyday activities, that richer understandings of obesity and children's bodies became apparent. We argue that without participant observation, our understandings of what children say and draw about healthy lifestyles may be limited by the striated spaces in which we conduct our research and the constraints that accompany the cultural politics of childhood and obesity.