How Can the Brain be Both 60% Fat and 85% Water?

I was recently giving a presentation on healthy eating to the lovely ladies of a local Women’s Institute. Towards the beginning of the talk, I described how essential healthy fats are within our diet. One of the stats I shared was that 60% of the brain is fat.

A bit later on, I was explaining that water is the foundation of life. At this point, I claimed that the brain is 85% water.

Both are facts that I’d been taught as part of my health coach training. But that didn’t stop one eagle-eyed audience member from raising an eyebrow. How on earth can the brain be both 60% fat and 85% water? Which one is right?

The brain is 60% fat

So firstly, the brain is 60% fat. It’s built on fat, although it runs on glucose. If you hold a brain, it apparently feels soft, squidgy and squelchy (according to neurosurgeons!). Yuck.

This means that dietary fats are crucial for good mental health. Especially since fats are the train that transports fat-soluble vitamins (A, D, E and K) to the brain.

But fats have been demonised over recent decades and have therefore been removed from many people’s diets. The rise in mental health issues over this same time period is stark.

Fats also play other vital roles within the body. They are necessary for the normal everyday function of the heart, liver, lungs, kidneys and immune system. They are important for healthy bones, cell walls, digestion, hair, skin and nails. And the body also utilises dietary fat for energy, so it helps keep us going throughout the day.

The inclusion of good fats in the diet is thought to promote several health benefits such as protection against heart disease, cancer, Alzheimers and depression. As well as reduced blood pressure and lower cholesterol.

And by good fats, I mean extra virgin olive oil, avocados, coconut oil, nuts, seeds and oily fish. I don’t mean the junk fats that are used in many processed foods such as trans fats, and hydrogenated fats and oils.

As with most foods, we should only be eating what the body recognises, rather than imitations and modified versions. Full fat milk. Butter rather than margarine. You get the idea.

The brain is 85% water

But the brain is also 85% water. In fact water makes up more than two thirds of the human body weight. Blood is 82% water and the lungs are 90% water.

Without water, we would die within a few days. And a mere 2% drop in our body’s water supply can trigger signs of dehydration such as poor short-term memory. It is thought that 75% of adults in developed countries have mild, chronic dehydration leading to daytime fatigue.

More seriously many backaches, headaches, mineral imbalances, digestive problems, hunger pangs and sugar cravings are caused by dehydration. Not to mention that when we starve our cells of water, they start to react differently. So it’s no surprise that how much you drink can affect your health.

So, how much water should we drink? The simple rule is to drink when you’re thirsty. Unfortunately, this doesn’t always work since our ability to recognise thirst diminishes as we age.

On average, men should drink about 3 litres and women about 2.2 litres per day. Although in reality this will vary depending on your age, activity levels, diet and health concerns, as well as the local climate (temperature and altitude).

It’s probably safe to assume you’re not getting enough, so try to increase your intake of pure water. And no, that doesn’t include coffee, tea, fizzy drinks, alcohol or energy drinks!

So, which one is right?!

Back to the maths problem… After much research, it turns out that both figures are correct. The brain is 85% water when it’s in our body. But if it’s removed and all the water is drained from it, 60% of the remaining dry weight of brain solids is fat.

So there you have it! Water and fat do mix and both are vital for the health of our brains. So, how are you making sure you get enough healthy fats and water in your diet? Do leave a comment below and let us know your top tips.

With love,

Angela x

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