Thirties are a crucial decade in our lives. And we aren't the only one saying it. There are several studies and research papers, stating why the 30s are so important. Some such papers conclude: it's the decade where you are likely to be the happiest (aged 33) and when you are likely to have most affairs; it's also the decade when you are going to be least satisfied at work. It's also the decade, in which, if you are not careful, by the end of it, the tell-tale signs of aging may become more prominent — from weakened knees, reduced metabolism, to a receding hair line, warns nutritionsit Karishma Chawla.

Cristiano Ronaldo of Real Madrid celebrates after scoring a goal against Manchester United in July 2015. Pic/Getty images