fasting before radiation treatment - Advanced Prostate...

Advanced Prostate Cancer

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fasting before radiation treatment

myamic profile image

What are the thoughts of fasting prior to radiation treatment for protecting against cytotoxic effects and also improving effectiveness of treatment.

40 Replies

You do not want to fast during'll find out first hand if you do. You don't want to eat before but that is not the same thing as fasting. In fact. eat some junk food along with your normal'll keep you regular

How would that protect against cytotoxic effects and improve effectiveness?

myamic profile image
myamic in reply to Tall_Allen Thanks

Tall_Allen profile image
Tall_Allen in reply to myamic

Thanks! I'll read it. I suggest you discuss it with your RO. A growling stomach from fasting may cause more bowel motion than if you eat. If so, the toxicity will be greatly amplified.

MateoBeach profile image
MateoBeach in reply to myamic

Most excellent review article on the therapeutic benefits and mechanisms of short term fasting. Thanks for posting it.

I did quick aerobic workouts just before my igmrt radiation treatments in hopes of improving radiation killing efficiency as per TA.

myamic profile image
myamic in reply to fmenninger


There is a video on YouTube “Fast & live” . I did two 500 calorie days per week in imrt treatments. I went from 233 to 165 . I went into undetch so far over five years. The theory is that the bad cells are more readily knocked off in a weakened state . Good luck

TomTom1111 profile image
TomTom1111 in reply to Lulu700

Did you really fast during radiation? It seems that would be the last thing you'd want to do. But maybe there is some benefit....I told my RO what I was eating prior to my starting IMRT and he told me I was eating too good and suggested I mix in McDonalds...too much fiber he said..

dhccpa profile image
dhccpa in reply to TomTom1111

Was he a heavyset gentleman?

TomTom1111 profile image
TomTom1111 in reply to dhccpa

Nope . In good shape..I got the impression that eating too much fiber during IMRT can cause issues.

dhccpa profile image
dhccpa in reply to TomTom1111

Thanks never had it but discussed with an RO two years ago. He mentioned stopping antioxidants but nothing about diet. I know a lot of people fast before and during chemo.

TomTom1111 profile image
TomTom1111 in reply to dhccpa

Chemo and Radiation are very different...both have the side effects and both work off the cytotoxic effects with is why eating too many anti-oxidants is not advises.

I''m just relaying my experience...I'm sure other have different experiences...all I know I had very little side-effects from RO except fatigue in the later stages...but nothing that stop me from working out and playing ice hockey.

Lulu700 profile image
Lulu700 in reply to dhccpa

My mo said mega dose vitamins have shown to promote death in us. I did 50,000 milligrams vitamin c IV’s bi weekly my first 18 months and during imrt . I escaped a hellish urology by doing so .

Lulu700 profile image
Lulu700 in reply to TomTom1111

I’ve done many things beyond western meds scope . Fasting was just one. High dose thc is another . My uro told me “ It doesn’t matter what you eat, you’ll be dead in 36 months. I never listened to him again .

TomTom1111 profile image
TomTom1111 in reply to Lulu700

If it wasn't for the hellish legal system in this country a lot of this nonsense we endure probably wouldn't exist....I've heard enough stories from doctors being sued for the stupidest things to cast most of the blame for this crap on the lawyers in this country.

IMO, lawyers == leeches.

myamic profile image
myamic in reply to Lulu700


MateoBeach profile image
MateoBeach in reply to Lulu700

👍. Why I do OMAD intermittent fasting daily.

Lulu700 profile image
Lulu700 in reply to MateoBeach

U da man !🤙🏽

TomTom, he asked you a question. No need for the vitriol. We all come here to hear differing points of views and we make our own choices. We appreciate your input and those of others.


TomTom1111 profile image
TomTom1111 in reply to Schwah

The reply that I responded to is no longer visible...I've only recently joined this site and in that short time the individual that I was responding too , which is no longer visible, has F-bombed me like 6 do not have the context of my response. I was not responding to the OP.

cesces profile image
cesces in reply to TomTom1111

Lots of angry old men here. Lol

I think it comes with age.

Just read about a guy with a pickup in chicago who was offended by some young asian couples picnicing in a large neighborhood median strip.

When they disregarded his orders to remove themselves, he returned and ran them over with his pickup.

After his arrest he apparently remained proud of his actions.

I seem to run into lots of similar angry old men on this forum as well.

Probably indicative of high levels of depression and low levels of life satisfaction among pca patients.

Lulu700 profile image
Lulu700 in reply to cesces

Cant get me no , no satisfaction! 😂

The very reason you are undergoing the treatment is to benefit from it's cytotoxic effects.

So dampening those effects isn't a good thing.

noahware profile image
noahware in reply to cesces

The point of the dietary intervention is to potentially dampen the negative effects on healthy (non-PC) cells, which I think is implicit in the "also improving effectiveness of treatment" part of the question. There is a lot of research into different methods of making chemo or radiation more toxic to cancer cells, RELATIVE to healthy cells, and dietary intervention has possibilities (but it seems more so with chemo than with radiation, judging by the available studies).

cesces profile image
cesces in reply to noahware

I was questioning the automatic almost anthromorphic assumption that if something is good, it knows to be good only to good cells and not to bad cells.

Without hard data, that seems to be a common assumption that many patients, who are predisposed to take supplements, seem to make.

That's all.

MateoBeach profile image
MateoBeach in reply to cesces

Read the article posted. Explains the differential stress responses of healthy vs cancer cells to short term fasting.

cesces profile image
cesces in reply to MateoBeach


I went back and read the first study.

It makes a case for a conjecture worth testing in a clinical trial with prostate cancer (probably a specific type of pca) and a specific type of chemo.

I would laud you to go take a look at the citations. They are about monkeys and mice and petri dishes. And various types of cancer. And appear to be cherry picked to support a conjecture worth investigating.

It is no more than that. This is valid advocacy for future clinical trials, but nothing more.

Biological systems are complicated.

People are drawn toward simple solutions of complex problems. Just read any opinion pieces in today's news.

My caution is that the weakest and most vulnerable of us are most vulnerable toward gravitating towards simple solutions to complex problems.

Without substantive clinical evidence, relying on fasting as an adjuvant for all types of cancer treatment of all types of cancer is logically dubious.

Like a lot of foolish people who actually take antioxidants during radiation treatment without consulting with their docs... thinking they are doing a good thing.

MateoBeach profile image
MateoBeach in reply to cesces

Thank you. Yes it is pre-clinical and animal models. Will not hold my breath for the definitive RCT for a free intervention! I am actually fairly well educated on the biology of these mechanisms. I already do intermittent fasting and ketogenic diet routinely for the other benefits that accrue. Easy to do and possibly have differential stress response on your side. No downside while awaiting further research.

lookup Dr. Valter Longo at the Norris Cancer center USC (The University of Southern California). Based on his work, it appears that during fasting healthy cells go into a protective mode and cancer cells are more exposed to the treatment. Longo refers to this as "differential stress resistance." There are ongoing clinical trials being done there so we will see the results at some point. In my own experience, fasting has been a critical part of my effort to mitigate the effects of ADT. I fasted during radiation treatment with no problems.

Lulu700 profile image
Lulu700 in reply to gyancey

I agree from my own experience .

cesces profile image
cesces in reply to gyancey

"I fasted during radiation treatment with no problems."

How would you know?

It may have helped. It may have hurt. But it would not be possible to verify one way or the other.

gyancey profile image
gyancey in reply to cesces

Hi CescesI could have phrased that better. What I meant to say was that I did not experience anything while fasting during radiation that was problematic. I played close attention to blood pressure, sleep quality, bowel movements, blood sugar ect.

As to whether the fasting helped the radiation be more effective who knows? I just know that fasting was not problematic during treatment. Trust me I am under no allusions that fasting cures cancer. I can state unequivocally that fasting has been of huge benefit in managing the horrible side effects of ADT.

I measure the following pre and post fast:

Complete blood count and chemistry pane

Cholesterol (Total, HDL, LDL)


Fasting blood glucose




Baseline measurements:

Total body weight

Abdominal Circumference

Body composition and/or body fat %

Blood pressure

All of these improved with fasting. Admittedly this is a N-1 so it needs to be taken with a healthy grain of salt.


cesanon profile image
cesanon in reply to gyancey

Sometimes n-1 is all you have.

Lulu700 profile image
Lulu700 in reply to cesces

I did it !

The studies by Dr. Longo are where I refer to. If I may ask , how many days did you fast before and after....Thanks

Spyder54 profile image
Spyder54 in reply to myamic

Myamic,I just read the study, it appears that the study is more about chemo, than radiation. But also appears as a possible source for tumor reduction. Appreciate you keeping the knowledge flowing.

gyancey profile image
gyancey in reply to myamic

I did the ProLon Fasting Mimicking Diet for five days during the first and last weeks of treatment. In addition to Dr. Longo's work you can look up the Buchinger Wilhelmi clinics in Germany and Spain, they have over 70 years of experience in therapeutic fasting and their results are impressive. On their website, you will find a lot of their studies.

Lulu700 profile image
Lulu700 in reply to gyancey


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