While everyone knows the five fruit and veg a day rule, Dr Michael Mosley has shared something you should do seven times a day.

The health guru, behind eating plans like the 5:2 and Fast 800, talked about how much water you need to drink.

Some sources claim you should aim for six to eight glasses of water a day, but others suggest less could be enough.

Fortunately, a simple toilet test could reveal if you’re drinking the right amount for you, according to Dr Mosley.

He penned on Instagram: “There is a lot of debate about how much water you should be drinking, but a really simple rule of thumb is trying to drink a large glass of water with every meal.

“That way, you won’t forget to do it, and you can check whether you’re drinking enough by counting how many times you go for a wee.

“You should be going for about six or seven wees a day. So as well as your five a day. Think seven wees a day.”

On a previous episode of Dr Mosley’s podcast, Just One Thing, Stuart Galloway, who is a professor in Exercise Physiology at the University of Stirling, shared the amount of loo trips that could signal you’re not drinking enough or drinking too much.

Galloway said: “If you’re only going three or four times per day for a pee then you’re probably not drinking enough. And if you’re going more than seven or eight times per day, then you’re probably drinking too much.

So, anything more or less than five and seven times could be a tell-tale sign you need to add a few cups or take away.

The warning signs of dehydration include feeling thirsty, passing dark-coloured urine, feeling tired, feeling dizzy and having a dry mouth and lips.

The NHS Eatwell Guide suggests you should aim for six to eight glasses of water and other liquids each day to replace normal water loss. But it’s not just water that can hydrate you, lower-fat milk and sugar-free drinks, including tea and coffee, all count too.

However, Dr Mosley previously revealed on the BBC Radio 4 podcast that the “old idea” that we should be drinking eight glasses of water a day “wasn’t based on any research”.

He said: “If you love water feel free but there really is no need to go mad. For most of us all we need to do is have a glass of water with every meal. It’s that simple.”