When Russian physician Dr Elie Metchnikoff first suggested, in 1905, that a simple fermented product was the key to long life, he sparked a craze that rapidly spread across Europe.

More than a century later, the trend is back in the form of this probiotic drink, though not everyone loves the flavour. For some, it smells like milk that has gone off.

And yet, it is a rich source of protein and calcium with huge gut health benefits and it cured my acid reflux - as well as helping me shed almost 9lbs.

Plus, it's affordable, easy to find in any supermarket. Can you guess what my health hack is?

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