According to the UN, the world’s population is expected to increase by two billion people, from 7.7 billion at present to 9.7 billion in 2050. But we are not only becoming more, but we also tend to live in cities and live longer. In a near future, children below age 5 will be outnumbered by persons aged 65 or above. What implications will this have for us, our lifestyle and our health?