This paper presents a novel view of the concept of cognitive enhancement by taking a population health perspective. We propose four main modifiable healthy lifestyle factors for optimal cognitive functioning across the population for which there is evidence of safety and efficacy. These include i) promoting adequate sleep, ii) increasing physical activity, iii) encouraging a healthy diet, including minimising consumption of stimulants, alcohol and other drugs including nicotine, iv) and promoting good mental health. We argue that it is not ethical (...) to promote or sanction the use of pharmaceutical drugs as putative cognitive enhancers without acknowledging the adverse effects on population cognitive health of failing to encourage the pursuit of healthy behaviours. We conclude with recommendations to increase the public health relevance of bioethical analyses of the cognitive enhancement debate. (shrink)