Australia's current age distribution is not uniform, having been influenced by past numbers of births and net migration. There are age groups with higher populations than other age groups and these will propagate into the future, causing the prevalence of some diseases to increase. We must act urgently to reduce the incidence of these diseases, develop cures, and improve treatments. It will be costly not to do so. Prevention of several diseases is to some degree influenced by diet and lifestyle, but the evidence suggests that this message is not getting through or is not being acted on.