Allow me to reintroduce you to an important idea, something I’m sure you intuitively know: you’re not the same person you were ten years ago, five years ago or even last year. You’ve changed physically, psychologically and probably personality-wise too. Your tastes and personal preferences are likely different, and you may no longer want or like the same things. And that’s OK. In fact, it’s more than OK – it’s the reality of who you are at this moment. From your metabolism and mindset to your health and happiness, the only constant in life is constant change. Everything and everyone is changing, whether you sign up for it or not.

A story from Greek mythology that illustrates this idea perfectly is the ‘paradox of the ship of Theseus’. It poses an interesting question that has puzzled even the most eminent of philosophers.

Theseus was a hero known for slaying a monster known as the Minotaur. Legend has it that when Theseus returned to Athens after slaying the Minotaur, his ship was given pride of place in the harbour there as a permanent reminder of his tremendous achievement. Each year subsequently, his brave voyage was reenacted. As the years passed, pieces of his ship, which was made entirely from wood, naturally began to weather and decay. In turn, each piece of wood that rotted was repaired and eventually replaced by a new plank, until the time came when every single original piece of wood in Theseus’ ship had been replaced. This raises the question – was it still the ship of Theseus, or was it a different ship? If it was different, then at what point in the repair process did it cease to be the original ship? Or was it still the same ship of Theseus by virtue of its function? Did the essence of the ship remain the same despite the frequent changes?

Now let’s extend this concept to your human body. Just like the ship of Theseus, your cells and body are part of a continuum of constant change.

Your body contains over 30 trillion cells with a daily turnover of around 330 billion cells, as older cells die and are replaced by newer ones. The vast majority of these are red and white blood cells, which live between several days and a few months, followed by cells that line the gut wall. Every 80–100 days, 30 trillion cells will have been replaced in your body – the equivalent of a brand-new you! There are also trillions of bacteria – collectively known as the microbiome – living in your intestines which weigh in at several hundred grams and replace themselves frequently.

Just like Theseus’ ship, you too are constantly changing. As well as the inner architecture of your cells, your thoughts and beliefs, attitudes and behaviours may well be changing every day. How you look and appear to the outside world is also changing in terms of how you are biologically ‘ageing’ – something that is influenced by a wide range of factors. Are you then sti