Refocusing on hydration and fasting

I’m not sure about you, but for me, there are two times of the year when it feels natural to take a step back and give ourselves a little more perspective on what we are doing and where we’re going. One is around our birthday, and the other is at the turn of the new year. And out of this process of reflection, it is normally the case that the topic of health is, at one point, highlighted as fundamental.

I’ve been thinking about health for a long time, and because of my training in physics, I regularly come back to first principles, which in this case means the basics: what are the basics, the most impactful aspects, those things that we should keep in mind above all others?

The reason it’s important to come back to the basics is that as our knowledge and understanding deepen, our perspective on how the various elements fit together grows more complete and also more subtle. In my current thinking, I believe the two most important things for health are optimal hydration and fasting.


It is odd, in many ways, that what most of us tend to be obsessed about, from the moment we get up to the time we go to bed, is eating. But that eating itself is in fact so secondary compared to not eating.

When we eat, we can nourish. But when we fast, what we do is repair, cleanse, and rebuild the bodymind from the inside out. But what’s critical is that the majority of these repair processes cannot take place unless we are fasting. Isn’t this enough to show us that fasting is on the whole much more important than eating for preservation of health? I certainly think so.

Now, when we do eat, what do we eat? For most of our evolutionary history, this was not a question we had the luxury to ask. Today, however, most things we eat are devoid of nutrition. And not only devoid of nutrition, but filled with anti-nutrients, like phytates and lectins, that prevent absorption of micronutrients and damage the lining of the digestive apparatus. So, what happens when this is repeated every day, month after month, year after year, decade after decade?

What happens is that we see the world in which we live. A world of sickness and disease, of damaged metabolic and digestive systems, weakened and compromised immune systems, premature ageing and death from chronic conditions that arise from overeating and malnutrition, and all of it normal, customary, expected. How stunning it is.


Optimal hydration is without any doubt critical to health for two very simple reasons: the first is that the function of every cell in the body depends on the continuous filtration of the blood by the kidneys that rely on optimal hydration to work well. The second is that macroscopically the body is like a bag of salty water: cremating our body leaves behind ashes that amount to 3.5% of the starting mass. That’s really not very much: for a 60 kg person, we’re talking 2 kg; and for an 85 kg person, it’s 3 kg of ash that remain. While optimal hydration is simple, it does require some effort.

We can’t drink too much too quickly. We can’t drink a lot of water without eating enough salt. And we can’t hydrate when the stomach is not empty. We can’t drink too much too quickly because the kidneys filter the blood at a particular pace which is equivalent to approximately 400 ml/hour. Drinking faster than this will dilute the blood (mostly the sodium) and force the kidneys to push water out of the system (through urine). We can’t drink lots without eating enough salt for exactly the same reason. And we can’t hydrate properly unless the stomach is empty because otherwise the water is stuck in there until the breakdown of the protein content is complete.

In conclusion

You can read a lot more about this in our articles that discuss fasting, digestion, and kidney function. The purpose of this post was to give a very short back-to-basics, and with it, an inspiration to refocus on these essential elements of health which are optimal hydration and fasting, and that are, in the end, very simple:

  • Drink approximately 400 ml of clean, filtered water per hour for a total of about 3.5 liters per day (before 20:30 to not get up at night);
  • Have approximately 1 to 2 teaspoons of unrefined salt per day with your one or two meals;
  • Eat a lot less frequently and in smaller quantities;
  • Avoid metabolically and digestively damaging food, and focus on nutrient dense animal foods and green vegetables.

That’s it.

2 thoughts on “Refocusing on hydration and fasting

  1. Back to basics… You are absolutely right. Fasting has become totally natural for me – I am fasting every morning without even thinking about it – but the drinking is more of a struggle. I will make it the objective of this year! Thank you Guillaume!

    Liked by 1 person


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