“DRINKING THREE LITRES OF WATER A DAY TOOK 10 YEARS OFF MY FACE”

British journalist Sarah Smith, 42, wanted to solve her headaches and poor digestion – and ended up looking a decade younger, too

You might think I’d have little in common with a camel, but we do share one useful skill: both of us can go for a very long time without water.

Usually I start my day with a cup of tea, then I might have a glass of water with lunch and one with dinner – that’s almost a litre in 24 hours. It feels like plenty, but apparently it’s not nearly enough.

After years of suffering headaches and poor digestion, I spoke to a neurologist and a nutritionist and both told me I should be drinking up to three litres of liquid a day for my body to function at its best. I decided to conduct an experiment – what would happen if I drank that amount every day for a month?

The photo of me taken the day I started this trial (pictured, right) demonstrates perfectly – and rather frighteningly – what a lack of hydration does to a face. I’m 42, but I have to admit I look more like 52. There are dark shadows under and around my eyes, which make me look exhausted, a profusion of wrinkles and strange reddish blotches, and my skin lacks lustre – it looks dead. Even my lips look shrivelled. My daughters tell me I look “about 100 years old”.

This is all classic evidence of poor hydration, apparently. Nearly every system and function in our body depends on water. It flushes toxins from the vital organs, carries nutrients to cells, provides a moist environment for ear, nose and throat tissues, and eliminates waste. Not drinking enough means all these functions are impaired, so I decided to drink three litres for 28 days. The results were astonishing...

WEEK ONE WEIGHT: 54KG WAIST: 71CM

Three litres is roughly 12 cups, which sounds like an awful lot. I visit my GP to be sure there are no adverse health implications to upping my intake so dramatically and he’s encouraging. “I suggest you have a big jug of water in the morning, another in the afternoon and another in the evening,” he says. “Your kidneys, which filter waste products from the blood before turning it into urine, will quickly feel the benefit, as they will be getting a good flush through.”

I usually have a wee three times a day: when I get up, before I go to bed and at some point in the afternoon. By the end of my first day of drinking more water, I’ve had six and my usually sluggish bowels are much more lively.

I exfoliate my face every day to try to get rid of dry patches before I apply moisturiser, but suddenly I seem to be breaking out in spots. Maybe it’s all the toxins coming out of my skin. A few days in, I’m still urinating five or six times a day but it’s clear now, rather than dark yellow.

I’m enjoying lots of cups of tea. My husband says that’s cheating, but the British Nutritional Foundation says “moderate amounts of caffeine do not cause dehydration, so they do count towards your fluid intake”.

I meet friends for a drink one night, remembering that alcohol is a diuretic (which promotes the production of urine) that acts on the kidneys. For every one alcoholic drink, your body can eliminate up to four times as much liquid. I assume a white wine spritzer is a good option as the alcohol is diluted with soda water, and I sip water between alcoholic drinks throughout the evening.

Hangover headaches result from dehydration as the body’s organs try to make up for a lack of water by stealing it from the brain – as a result, the brain shrinks. Headaches result from the pulling on the membranes that connect your brain to your skull. Ouch. Luckily, I wake up hangover-free.

For years I’ve been doing 10 minutes of yoga after I get up, but I’ve felt stiffer over the past six months. Since I started drinking more, my flexibility has improved.