FASTING AND AUTOPHAGY PART 5 – WHY FIFTEEN GRAMS OF PROTEIN IS A MAGIC NUMBER

This article is copyright © Nils Osmar 2019.

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I’ve mentioned in my previous articles about fasting and autophagy that the body uses 15 grams of protein to keep basic functions going (i.e., to keep the heart, lungs and other organs operating).  I
f you’re eating less than this amount of protein, you’ll move into autophagy to make up the difference.

Imagine for a moment that you’re living on a ridiculously low-protein diet. The only things you have around to eat are iceberg lettuce, parsley and celery.  You eat a big bowl of salad, but it only has 10 grams of protein in it… too little to carry on basic bodily functions. Why would you still be alive, eating this way for even a few days? And how could you possibly survive a water fast, in which you’re not eating any protein at all?  

The answer is that your body goes into autophagy to get the other 5 grams it needs to carry on the basic functions of life.  It starts scavenging debris, bacteria and viruses and other clutter from your cells and breaking them down into amino acids which it then re-assembles into proteins.

We don’t have to teach the body how to do this; it’s designed to go into autophagy during starvation, just like the bodies of all other complex animals on Earth, by millions of years of evolution. 

Point being – when you are fasting – if your goal is autophagy – you don’t need to go into a panic about having “broken” your fast if they accidentally ingest a few of grams of protein. As long as you keep your protein levels under 15 grams a day, autophagy will go on. Autophagy won’t stop if you eat a tiny amount of protein when fasting. You could even have the iceberg lettuce salad I mentioned above, and you’d still be in autophagy.

People sometimes get panicky, thinking that even a speck of protein will undo their fast. I’ve seen websites in which people are in a panic, for example, about the notion of adding a little cream to their coffee.

Let’s say you did have a little cream, while fasting. There are 0.3 grams of protein in a tablespoon. You’d have to drink 45 tablespoons, or 3 full cups of cream in a day, to be getting enough protein in your body to stop autophagy. 

This is why doctors and others have come up with “fasting mimicking diets” that keep the protein below 15 grams, as a way for people who want to experience some benefits of fasting, but not to really fast, to do so.

I hope it’s clear that I’m not recommending eating a diet that’s under 15 grams of protein every day. Even autophagy has its limits.  The body needs dietary protein. And it needs other macronutrients and macronutrients found in food.

When you fast, you’re building up a deficit of nutrients. When your fast is over, in my experience, it’s good to eat a diet that’s very high in nutrients (particularly taurine) for a few days. (As Dr. Valter Longo has pointed out, it’s not the fast that creates stem cells and give you a regenerated immune system — one of the profound benefits of fasting — it’s the refeed after the fast. You need lots of high quality protein and other nutrients during that refeed.)

P.S. The idea of fasting is to give your body a break from food. For many people, water fasts (supplemented by electrolytes) are the easiest way to accomplish this. But hopefully this should clarify why adding a tiny amount of cream to your coffee when fasting, or chewing on a stalk of celery if you get hungry, won’t break your fast in the sense of moving you out of autophagy.  More about autophagy, fasting and anti-aging

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