Fasting For 3 Days Regenerates the Entire Immune System

Jumping for joyBy Heather Callaghan

Research finds that fasting “flipped a regenerative switch” leading to new blood and  new immune system creation – in just 72 hours

Results from a recent study fall into the category of “remarkable,” as it was described.

Researchers from University of Southern California were looking for extra immune help for chemotherapy patients, and found an answer for everyone. For chemo patients, the elderly, the chronically ill, even those with auto immune diseases.

Longer fasts use up the body’s glucose stores, but they also breakdown and rebuild the white blood cells – literally rebuilding a new immune system.

Prof Valter Longo, Professor of Gerontology and the Biological Sciences at the University of California explains:

It gives the ‘OK’ for stem cells to go ahead and begin proliferating and rebuild the entire system. 

And the good news is that the body got rid of the parts of the system that might be damaged or old, the inefficient parts, during the fasting. 

Now, if you start with a system heavily damaged by chemotherapy or ageing, fasting cycles can generate, literally, a new immune system.

By having the white blood cells depleted, it triggers stem cell based reproduction of new born immunity.

The Telegraph reports:

In trials humans were asked to regularly fast for between two and four days over a six-month period. 

Scientists found that prolonged fasting also reduced the enzyme PKA, which is linked to ageing and a hormone which increases cancer risk and tumour growth.

Longo continues:

We could not predict that prolonged fasting would have such a remarkable effect in promoting stem cell-based regeneration of the hematopoietic system. 

When you starve, the system tries to save energy, and one of the things it can do to save energy is to recycle a lot of the immune cells that are not needed, especially those that may be damaged. 

What we started noticing in both our human work and animal work is that the white blood cell count goes down with prolonged fasting. Then when you re-feed, the blood cells come back. So we started thinking, well, where does it come from?

But the wonders didn’t stop at this point.

They realize that chemotherapy causes “significant collateral damage” to the immune system. That’s when they discovered that fasting for just 72 hours could protect cancer patients from the toxic effects of chemotherapy.
Now they wish to check fasting’s effects on other organ systems and physiology – not just the immune system.

One criticism I have with the presentation of the information was the constant use of the word “starvation.” I have never thought of interchanging those words because fasting often has intent behind it – sometimes spiritual, health conscious or both. It is associated with regeneration, not a breakdown.

Picture the difference between someone who intends to do a fast for 10 days (or however long they are intuitively led to) and someone who is going hungry for 10 days or purposely starving themselves – sometimes associated with the negative mental aspects of anorexia. Or someone who “starves” themselves to fit into a dress or take a misleading before/after shoot to promote a diet pill. Starvation is associated with the
effects of muscle catabolism. There’s a difference!

Here are some press releases showcasing other fasting medical breakthroughs:

Please, please, do consult with your preferred health practitioner for guidance of if and how to do a fast that’s right for you.

Here is the ultimate book I’ve found on fasting – Fasting to Freedom, by Ron Lagerquist & Tom McGregor. It was encouraging and motivational with safety helps. It included helpful information for hypoglycemics and diabetics. Note: the book is from a Christian perspective. It also warns against ever doing a water fast – most of us are too toxic and would go into a harmful healing crisis. It’s about juicing with mostly vegetables to maintain nutrients during a fast. Anyone, especially diabetics/hypoglycemics might also enjoy using a Nutribullet which maintains even more nutrients/fiber/seeds of the plan and isn’t so messy (I’m happy with mine).

PS – A naturopath shared another secret way to kick the red and white blood cell rebuilding into high gear…

Can you guess what it is?

Give Blood.

Heather Callaghan is a natural health blogger and food freedom activist. You can see her work at NaturalBlaze.com and ActivistPost.com. Like at Facebook.


  • ok what happens when one has a hyper-active immune system, such as is found to be the cause of such diseases as multiple sclerosis, lupus, rheumatoid arthritis, etc, and one fasts for 3 days thus "generate, literally, a new immune system." ?
    wouldn't that kick one's respective disease into high-gear?

  • Anonymous

    Keep an eye on this page, I will try it and report back.

  • Anonymous

    James, I would say in those cases the affected person would have to do more research, and in particular, have their doctor (etc)* more closely involved, but the point of the article is that for say most people it'd be a good idea.
    * Caveat: how knowledgeable is your qualified medical practitioner on nutrition etc, how many times have they EVER mentioned it? (In my case, my doctor NEVER mentioned it).

  • Anonymous

    Perhaps the "new immune system" won't be hyper-active, or perhaps not as hyper-active?

  • Anonymous

    What are those of us who are so neutropenic that we're told to not have any fresh or raw foods (which includes raw fruits and veggies) supposed to do? What's the benefit/risk ratio for us?

  • Im confused by this statement "It also warns against ever doing a water fast – most of us are too toxic and would go into a harmful healing crisis. It's about juicing with mostly vegetables to maintain nutrients during a fast". I thought fasting was no food? And you cant drink water?..dont understand, and what is the toxic part about?

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