Energy drinks are increasingly listed as the vice of people young and old - despite concerns over the impact on consumer's health.

So Evening News reporter Francis Redwood cut the drinks out of his diet for a week - here's how it went.

When we're tired a lot of us enjoy a cuppa or a mug of coffee.

What wakes me up is a cold, refreshing energy drink.

For me the impact is instant - even after the first sip I feel better geared up for the day.

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This isn't a new habit. On and off for the past decade I have had one or two of these sugary delights a day.

To put this in perspective - this works out to around £900 a year.

So the habit has cost me an eye-watering £9,000 so far.

And not only is this bad for my bank balance but my health as well.

A recent study from the British Medical Journal showed that up to a third of children have at least one can per week, with some even having them daily.

Experts have now issued a fresh warning of the impact that drinking too many can have on children, causing headaches and sleeping problems.

Now I would not be classed as a youngster - but I don't smoke, drink tea, coffee or alcohol and get plenty of exercise.

%image(15614522, type="article-full", alt="Francis struggled to come to grips without energy drinks, saying "I had a constant headache and the shakes."")

But I was challenged to give up my vice for a week.

I had some reservations going into it and after the first few days they felt justified.

I had a constant headache, the shakes and an overwhelming urge to just go to the local shop and pick up a can of the sweet stuff so I felt better.

%image(15614524, type="article-full", alt="By day five Francis felt like he was able to function normally without reaching for a can of energy.")

However, after having persevered and the days ticked on by I started to feel better - if not a little tired still.

By day five I felt like I was able to function normally without reaching into the fridge for a burst of energy.

With the experiment finished, do I still feel the need to crack open a can of Monster? No.

But after my week off the drinks - which coincided with a week off work - I have found the return to the office meant I didn't need the boost.

It's something I'll look to cut down on but maybe not for good.

How much caffeine is actually in an energy drink?

While some people stay clear of energy drinks for health reasons, they can still often be found with a cup of coffee in hand.

But is one better than the other?

A 16 to 20oz coffee from chains found in the city can contain anything up to 200mg of caffeine in sweetened products.

This is compared to 160 mg found in a Monster energy drink.

However the impact does wear off faster.

An energy drink can dwindle after two or three hours, a coffee can stay in a drinker's system for up to six.

Meanwhile caffeine pills like Pro Plus contain up to 200mg of caffeine.

For a more subtle kick of energy a Coca-Cola or Pepsi will give consumers anywhere between 34 to 38 mg, while an organic tea can imbue people with around 90 mg of energy.