Why do I need to drink more water?

Everyone bangs on about being hydrated.  But do you ever think about why?

When your body’s low on water, it starts rationing like it’s preparing to run away from a sabre-tooth tiger.   Some really important bodily processes that keep you well? They just... stop.

Here are some of the surprising things your body can’t do properly when you’re dehydrated:

💧 Burn Fat Efficiently

Fat metabolism requires water.

Specifically, your liver needs water to convert stored fat into energy through a process called lipolysis. 

Without enough hydration, this process slows down and your body leans on muscle instead. So if you’re trying to lose weight, skimping on water is a bad idea.

💧 Think Clearly and Stay in a Good Mood

Your brain is around 75% water, so even mild dehydration (just 1-2% of body weight) can shrink brain tissue, slow down neural communication, and increase the stress hormone cortisol. 

That means more brain fog, trouble concentrating, poor short-term memory, and irritability that rivals toddler-level tantrums.

💧 Digest Food and Poo Properly

Water is essential for making stomach acid and digestive enzymes, as well as keeping things moving smoothly through the intestines. 



When you’re dehydrated, your body pulls water from your colon to keep more vital organs going, making stools hard and difficult to pass. Cue bloating, constipation, and that lovely “food baby” feeling after meals.

💧 Sleep Deeply

Hydration affects your production of melatonin and cortisol, the hormones that regulate your sleep-wake cycle. Dehydration can also cause your heart rate to stay elevated at night and increase your core temperature, both of which mess with deep, restorative sleep.

💧 Recover from Exercise

Water helps transport nutrients to your muscles, flush out metabolic waste like lactic acid, and regulate body temperature during and after workouts. If you’re not hydrated, expect longer recovery times, more soreness, and a higher risk of injury or cramps.

💧 Smell things properly

Hydration affects your mucous membranes, including the ones in your nose. When you’re dry, those membranes don’t work as well, which can dull your sense of smell. And since smell is 80% of taste, your food and coffee might start tasting bland too.

So how much water should I drink?

Aim for around 35ml of water per kg of body weight each day (that’s about 2.3 litres for someone who’s 65kg). If you exercise, drink caffeine, or are experiencing a heatwave drink even more than this.

And no, tea, coffee and alcohol does not count towards this total...sorry.

💡 Quick hack: Add a pinch of sea salt or a splash of coconut water to your bottle once a day to improve absorption and replace electrolytes. Just chugging plain water all day without minerals can make you pee it all out faster than your body can use it.

Hydration is the least sexy health tip and one you will have heard before. 

But honestly - I've had clients pay me good money for detailed dietary advice who feel better simply from drinking more water...

P.S. Want a weirdly effective trick? Drink a glass of water after every trip to the loo. Not glamorous, but it works.