Adequate hydration has many benefits. So it’s no surprise that social media abound with fads and hacks on how to achieve it. One of the more well-known trends is the #gallonofwateraday ...

But it’s a huge amount of water to drink every day – over twice as ... to the two-litre rule or the gallon challenge. “The guidance about drinking 1.8 to two litres a day is based on the ...