The Complete Guide to Hydration

guide to hydration blog

share this post

Instinctively you know that staying hydrated is important.

You were probably told by your parents and others from being a child that you need to make sure you drink plenty.

Well, your instinct and parents would be right on this topic!

There are a whole host of benefits associated to being well hydrated on a day-to-day basis, along with a myriad of issues linked to being dehydrated.

To name just a few of the benefits, water is needed for;

  • Transport of hormones and nutrients around the body,
  • Lubricating joints to help reduce impact,
  • Providing a protective cushioning to the nervous system.

Water also plays a role in the transmission of light in the eyes for vision as well as sound in the ears.

It’s safe to say life without water is impossible.

When you consider that around 60% of the human body is made up of water it all starts to make more sense as to why this whole hydration thing is actually quite important.

Outside of the common benefits you might think of that are associated with being well hydrated there are a few that really struck a chord with me and I think will with you too…

Hydration and your mood

mood and hydration
Being dehydrated by just over 1% of your bodyweight has been shown to have a negative impact on your mood.

The only thing worse than being in a bad mood yourself is being around someone in a bad mood!

So, what if something as simple as making sure you drink enough water each day could help to change this?

I’m not saying drinking water will be the stroke of genius that keeps a smile on your face all day long, but it is a relatively easy place to get in a quick win.

Hydration and your diet

Hydration and diet
A study recently showed that there was a positive link between people who drink more water and the quality of their diet in general.

In simple terms, the more hydrated you are the better your diet tends to be.

It’s worth noting here that many of the foods you would normally associate with a healthy diet also tend to have relatively high-water content too.

Now, it might seem quite obvious to link a good diet with drinking more water, but this gets more interesting when you delve into the logic behind the link.

What you’re seeing here is the positive impact of a keystone habit, the keystone habit in question is drinking water.

Keystone habits have the ability to inform every other habit in your life. I like to think of them as the ripple that cause a wave.

Take my own example shown below.

A while back when I started researching the topic of hydration I decided to set myself a challenge, to drink 2 litres of water each day.

This was party because I wanted to reduce my reliance on tea and coffee, but also because I had started to see a whole host of other benefits to staying hydrated that appealed to me.

Two of those benefits were being able to maintain focus for longer periods and remain alert.

For reference I was using coffee for this before.

Keystone Habit Effect

Now the example above opened my eyes to some unexpected results.

First off, remember I was aiming to reduce my coffee levels and stay more alert throughout the day…

Inadvertently I also started to see my skin become more vibrant and I also felt a higher desire to hit the gym with more vigour too.

So, from just working on drinking more water I had created a much bigger response across a whole host of different areas.

This is the power of a Keystone Habit.

Hydration and your metabolism

Hydration and metabolism
There are numerous studies that have shown drinking water can boost your metabolic rate, but one particular study showed the effect of drinking 500ml of water….it increased the metabolism in its subjects by up to 30%!

This rise in metabolism is mainly brought about by the body having to warm up the water being consumed.

Your body has to use up energy to heat water through a process known as thermogenesis, the creation of heat.

The authors of the study propose that drinking 2 litres per day will bring about an increased energy output by around 400 KJ.

400KJ of energy works out to around 100 calories being used by the body.

Another quick win.

Now we’ve established the fact that being well hydrated is indeed good for your health in more ways than you might have thought, the next question to be asked is…

How much water do I need to drink?

How much water?
Putting this question into google (or any other search engine) gives a wide variety of recommendations, for example;

  1.  8 x 8oz glasses per day.
  2. Men need 13 cups whilst Women need 9 cups per day.
  3.  In the UK drinking 1.2 litres per day will stop dehydration.

And more…

The fact however is that no one actually knows what the exact amount of water is we should be consuming each day.

One study done by researchers at Dartmouth Medical School even went in search of the answer to where our 8x8oz rule came from….and guess what?

This is what they found…

“No scientific studies were found in support of 8×8”

What it did find was that the most likely link between the advice to drink 8 glasses of water per day came from a book published in 1974 by a prominent researcher at the time called Frederick J. Stare, in the book he suggests the following.

“How much water each day? This is usually well regulated by various physiological mechanisms, but for the average adult, somewhere around 6 to 8 glasses per 24 hours and this can be in the form of coffee, tea, milk, soft drinks, beer, etc. Fruits and vegetables are also good sources of water.”Frederick J. Stare

This begs the question as to why such scant evidence is available to back up the advice given out by public health boards across the globe…

Maybe that’s a whole new topic to explore another day.

But for now, back to the original question of just how much water you need to drink each day?

With no real evidence to suggest how much we should drink the alternative way of looking at this topic is to think of the ideal range being a level whereby dehydration is not present.

For this approach you need to understand in a little more detail what dehydration is and also what markers or signs we can use to measure it by.

How do I know if I’m dehydrated?

There is no gold standard of assessing hydration levels or dehydration levels according to researchers at University of Connecticut, however using a variety of indicators to see if someone is dehydrated might be the best route forward.

Those indicators include;

  • Thirst
  • Urine colour
  • Mood
  • Tiredness
  • Hunger
  • Dizziness
  • Headaches
  • Reduction in Bodyweight

From the list you’ll see there are quite a few options to choose from when assessing whether or not you are dehydrated, but some are more easily integrated than others to your day-to-day routine.

For example, urine colour of dark yellow / orange combined with a reduction in bodyweight from would be a pretty strong indicator of being dehydrated.

Granted that for this you would need to know your normal baseline weight on a day-to-day basis first off.

Whereas, although being tired and in a bad mood could be due to dehydration it could also be due to the fact you had a poor night’s sleep and are therefore a little grumpy first thing in the morning.

You see, it’s not quite so clear cut.

So, what is the best way of assessing whether you are dehydrated or not?

From experience keeping a journal throughout the week of the fluids being consumed along with a note of the indicators mentioned previously is a good way to start.

After all, the more data you have to work with the better insight you will gain.

How food and drinks impact your hydration status

It’s very easy to forget that fact that your overall water intake throughout the day comes from more than just what you drink.

70-80% of the hydration your body requires each day is met by drinking fluids leaving the remaining 20% – 30% of daily fluid comes from the foods you eat.

It’s important then to better understand the types of foods that contain water (known as food moisture) so that you can start incorporating them into your daily meals.

Check out the list below to see the water percentage of common foods.

  • Tomatoes (95%)
  • Courgette (93%)
  • Celery (92%)
  • Cauliflower (92%)
  • Asparagus (91%)
  • Broccoli (90%)
  • Garden Peas (90%)
  • Carrots (89%)
  • Onions (89%)
  • Pears (85%)
  • Apples (75%)
  • Eggs (75%)
  • Fish (70%)
  • Chicken (60% – 70%)
  • Beef (60% – 70%)

This will probably come as no real surprise to you but, the most obvious way of increasing the amount of water you consume through the food you eat is to create meals based around meat and vegetables as these also contain high percentages of water too.

Does drinking caffeine impact my hydration?

caffeine and hydration
The answer to this question is yes and no!

In fact, when looking at the impact of caffeine on hydration, it turns out you can consume around 400mg caffeine per day without having any negative impact on your body’s hydration level.

400mg of caffeine per day was also suggested to be ideal for taking advantage of the positive benefits associated with drinking tea and coffee, those being;

  • Cognitive function
  • Mood
  • Performance

The researchers that gave this recommendation analysed 41 different studies ranging a 15-year span looking at the impact of caffeine consumption on hydration, so it’s fair to say they really did do their homework on this one!

To break things down for you this is what common sources of caffeine look like…

Caffeine Table

(caffeine levels stated in the table above are best estimates and may vary depending on brand, origin etc)

It’s worth noting at this point that many people overconsume caffeine throughout that day, so using this chart as a guide is a great starting point if you need to start getting a grip on your tea and coffee consumption.

One way to start controlling your caffeine intake each day is to get a clear picture of just how much you consume in the first place. This is where keeping a journal becomes an interesting tool to use when assessing hydration levels as it will allow you to check back and find trends linked to the amount of fluid you consume each day.

Does drinking alcohol impact my hydration?

Alcohol and hydration
Drinking alcohol makes you urinate more…FACT.

This happens due to alcohol reducing the release of a hormone known as vasopressin.

The role of vasopressin is to prevent urine production when you are dehydrated, so your body can try and regain its water balance.

When alcohol interferes with vasopressin production your ability to hold onto the fluids you are consuming reduces and this is why once you break the seal, you start working your way towards being dehydrated.

It is thought that with the increased rate of urination comes a depletion of electrolytes (sodium, magnesium, potassium) which contributes to the ensuing hangover.

So, with this in mind trying to offset the oncoming dehydration and hangover by drinking more water may not work, due to that extra water being urinated out of the body before it has chance to be absorbed.

The solution then is quite simply to cut down on the alcohol, unless you’re ok with a hangover and being dehydrated.

Creating your hydration strategy

Now you’ve learnt all about the different elements of hydration and how to assess whether you are dehydrated or not it’s time to put a plan of action in place.

Remember, not only will staying hydrated have a positive impact on the food you eat day to day, it also helps to boost your mood and metabolism!

Journaling your fluid intake

Step one of the hydration strategy is to better understand your current fluid intake by journaling.

Not only should you track what you drink but also how you feel too.

Pick 3 points in the day, ideally first thing in the morning, mid-day and evening then write down 3 things you feel at that point.

It could be that you are full of energy or feeling lethargic. Finding it easy to focus or fuzzy headed. Happy or sad.

Whatever comes into your head first this is what you should journal.

Do this for at least 3 days and look for any trends that show up.

Using a journal such as BestSelf Journal is a solid place to start.

Limit caffeine intake

400mg per day is the ideal range whereby you get the benefits of caffeine without the negative impact of dehydration.

Look back at the caffeine chart in this article to figure out how many coffees and teas you can have each day.

Aim to incorporate alternatives using fresh fruit or herbal teas such as those shown below.

Caffeine Subs

Eat more fruit and veg

This one sounds so simple, but remember here that for habits to stick the changes need to be easily installed.

Most fruit and vegetables contain higher levels of water (food moisture) and will help contribute to your daily fluid intake.

Building your meals around these foods is a quick win both for hydration and also your nutritional status too.

(This Chicken & Homemade Slaw recipe is a personal favourite that can help out here.)

Invest in a good water bottle

Staying hydrated and drinking more water throughout the day is much easier if you have a water bottle close to hand.

The repetition of sipping little and often slowly becomes ingrained into your list of subconscious actions.

Habits are brought about by repetition, upon repetition, upon repetition.

Here are a few of my own favourite bottle options…

Chilly’s Water Bottle (

B-on-1 (

Find more water bottle recommendations here (

If you enjoyed reading this article I have no doubts you’ll love staying up to date with all we have to offer at Real Food Function.

You can stay in the loop by subscribing to our mailing list where you’ll get all the latest content in the form of amazingly simple healthy recipes along with insight into our philosophy behind what truly works when it comes to creating a healthy lifestyle and results that stick.

Best of all you can get started straight away with 5 of my favourite recipes!

Get my Top-5 Energy Boosting Recipes for Free.
Sign me up!

share this post