Improving Metabolism With Intermittent Fasting


Chances are that if you read this blog, you live in a developed country. Food is readily available.

Look around you. There is plenty of food. Plenty is not the right word. We love food. We swim in food. We adore food so much we have large, humongous signs outside. We have *temples* dedicated to food on every block. Our love life is around food. We give food to others to show how much we care. Or we deprive kids of food to punish them. We bestow moral values to food and our whole belief system is centered on the idea that food, or more food, is always good.

Well I have an opinion that most of us, or pretty much, the majority of us will find not like, or at least not understand. I think alternating periods of fasting and regular eating can actually be good for you. Fasting here means not eating anything solid for one or two days, making sure to drink plenty, and then going back to your regular diet (preferably Mediterranean diet) for at least a couple of months before fasting again.

So why would I want to starve myself?

I believe first that the abundance of food is actually killing us little by little. Most of the food we buy are super-charged with calories. All of them are fortified with extra-calcium, extra-iron, extra-this and that. When you get anything at a coffee shop, chances are you just won’t get black coffee. What about pumpkin flavor? A little bit of cream on top? And soya milk? And why not a bit of honey and cinnamon? And why not some matcha. And a muffin to go with all these. With blueberries.

These all sound good. Sure, we’ve all read somewhere about the beneficial effects of soya, cinnamon or blueberries. Except we’re stuffing a dustbin that’s already full. Soon the dustbin is overflowing and going to crack open. The dustbin is your liver – and many other organs we’re abusing in the process.

The idea of fasting is giving a rest to these ballooning dustbins we have inside of us and if we are lucky, cleaning them up. It’s in essence, getting rid of the excesses society has been giving us for decades.

Our ancestors never had this problem. They didn’t have a fridge or an elaborate industrial system. Food supply was a daily issue. In winter, or when times were rough, you would have starvation. On the other hand, when the hunters came back home, or when the “gods” were good, you would have plenty of food. Alternating between periods of fasting and plentiful food was the natural cycle, and perhaps prevented metabolic diseases such as obesity or diabetes to progress in prehistoric societies.

Back to 2017, there are three ways to do this:

  • Caloric restriction diet (CRD) means eating 10 to 15% less than your daily caloric needs. You still get all your vitamins and macro nutrients, but less of everything. This can be a long-term diet, however there are many drawbacks for exercise and physical performance. You will also need daily motivation, and the discipline of a monk with its life of restrictions.
  • Prolonged Fasting (PF) means fasting more than 5 days, up to 21 days, but still having all fluid intake. It’s usually done only once or twice a year, and is done in a special environment where you have assistance and ideally medical supervision. While interesting, it’s not practical for most of us.
  • Fasting-Mimicking Diet (FMD) also known as Intermittent Fasting is alternating days of fasting with a regular diet, with food, ad libitum. You skip food for a day or two, then follow a regular diet for a couple of months, before fasting again.

FMD is the most practical. You can work, go on with your lives. You might have a grumbling stomach but still have energy to run, jump, go to events and meetings. That’s what I did recently.

So … does it work? I lost a few pounds, feel more present, and less bloated. If you want evidence, recent research on FMD is more interesting though than someone’s personal anecdote 😀

In a randomized clinical trial with subjects fasting for 5 days every month, subjects saw fasting blood glucose fell by 11%, human growth hormone by 24%, a 3% reduction in body weight, lower oxidative stress and substantial signs that the bodies were regenerating. This means the subjects saw their risk of cardiovascular disease or diabetes decrease and signs of slowed ageing.

It is very important to note that in this study, like all others, all subjects followed a regular maintenance diet, without restriction between periods of fasting.


Another randomized clinical trial was done on patients with multiple sclerosis (MS), an autoimmune disease. Those who followed a Fasting-Mimicking Diet saw their symptoms alleviated. Researchers found FMD to be safe, feasible and potentially effective for MS patients.

Another study on 2122 women demonstrated that fasting improved glucose control and could decrease breast cancer risk. Another study on obese objects demonstrated similar effects, as well insulin decrease by 57% (more than half!)

Apart from hunger, and non-adherence to prescribed diet (meaning a few subjects couldn’t stand fasting and stopped following the experiment), the researchers did not notice any adverse effects in these 4 studies.

Unfortunately there are no large scale studies. All studies done on yeast, mice, monkeys and the little done on humans all point out that fasting have protective effects against age-related diseases. See a summary here.

What’s more, they also observed fasting slowed down ageing and encouraged regenerative processes. How come? A few researchers suggest that during fasting, the self-cannibalistic process of autophagy is encouraged, cleans up the bad cells and protects us against infections, cancer, cardiovascular disease, aging and disease. Whereas, during periods of eating ad libitum, damaged cells accumulate, along with DNA mutations, and tissues degenerates. This is what you see in the graph below (left being fasting):


As you can guess, the research is new. It’s not very popular. Most of us want to believe that it’s by eating an exotic super food that will get us cured or get extra energy. It is not logical to think that an ABSENCE of food might be actually good for us.

In this case, all signs and smoke point out that Less is definitively More.

If you are curious – I recommend skipping dinner next time. If you don’t observe any adverse effects, try fasting for one full day the next weekend. Make sure to eat without restriction after fasting. If it is still good, the go for the full weekend. Skipping food for a day or two won’t hurt you. Actually, the vast majority of recent medical research point out it might actually be good for you. Even if you are training or perform, fasting + exercise can have combined beneficial effects.

Let me know what you think in comments!

3 thoughts on “Improving Metabolism With Intermittent Fasting”

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