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Fasting for chemo

Posts: 92
Joined: Sep 2012

I am starting folfiri and avastin next week. I have come across some research in fasting before chemo which indicates that it can help in reducing side effects and increase the effectiveness of the chemo. Does anyone here do this? If you do, what is prior schedule? Do you take the steroids on an empty stomach?

Posts: 2215
Joined: Oct 2011

I have heard of that but i don't recommend it. I don't see how it will make a big difference in side effects. More importantly it is VERY hard to eat while on chemo and you will already have an empty stomach. I did the opposite and ate a really good meal before chemo knowing that I would hardly be able to eat for 2 days. I would force myself to eat whatever I could stomach while on chemo in an effort to keep from loosing too much weight. Drink lots of fluids especially if you get diarrhea or vomiting.

Good luck, and let us know how you did.

BusterBrown's picture
Posts: 221
Joined: Mar 2005

I think J.Anderson is right, you want to eat when you can. As the chemo starts to wear on your body, you'll need to eat lots of nutritious food to regain your strength.  Follfiri made me nauseous. However, I found that by eating my nauseua usually went away. As you go along in your treatment you will figure out what works best for you.  Bon appetit!

lp1964's picture
Posts: 1240
Joined: Jun 2013

...with my friends above. Chemo depletes your energy to the minimum and you need to replenish that. If you don't have any reserves you may feel aweful. Chemo gets broken down by the liver, so feeding the liver with nutrients and vitamins is essential. I learned this in a hard way recently. I fasted for an ultrasound for 16 hours and my stool turned pail immediately which is the sign of liver distress. That was followed by 2 days of diarrhea and staying in bad. 

As janderson said plenty of liquid is also essential, even if you don't have diarrhea and vomiting. If you do even more.

I rarely drank coffee before, but during chemo after a meal it did wonders to my energy. 

I say eat and drink as much as you can. Keep carbs down. Get your energy from proteins and good fats. For liquids it's not just water, also eletrolits like gatoraid.

Good luck and keep us posted.


serenity101's picture
Posts: 82
Joined: May 2013

I would love to hear how it goes for you if you decide to try it. I haven't tried it, but may (or may not) try it when I eventually switch from FOLFOX to FOLFIRI if I have side effect issues. I mentioned it as a possibility to my oncologist. After calling one of the researchers (at Mayo Clinic), he agreed that we could look into it when the time comes. Since human studies are just beginning, I wouldn't do it without his knowledge and consent and careful monitoring. The mouse studies looked good, but that doesn't necessarily translate into good results in people, although some very small, early, short-term studies look promising. All still very experimental, though.

The hypothesis is something like this (for those who haven't heard about it): normal cells go into protective mode when you fast, and cancer cells don't, so when you fast before chemo your normal cells are primed to protect themselves from the chemo and the cancer cells want to gobble it up. Which should mean less side effects and maybe more effectiveness.

Again, it is all still very experimental, but the research is coming from legitimate institutions, so it is a risk I might be willing to take under the right circumstances and in cooperation with my oncologist. Keep in mind that I am expecting to be on chemo for life, so I don't get to plan on side effects going away when I finish chemo. 



LivinginNH's picture
Posts: 1458
Joined: Apr 2010


Not a good idea.  As the others have stated, why would you want your body in such a weakened state before chemo hits it!!??   My Rick's doctor told him to ALWAYS eat a decent breakfast before treatment, and eggs worked out well for him.   He wouldn't have an appetite for days afterward, but coconut water did help to prevent dehydration.  Bottom line, don't believe everything you read on the internet. 

Take care.

saussureainvolucrata's picture
Posts: 54
Joined: May 2013

my mom was dx-d with colon cancer stage 3c in may, had a surgery, and 6 sessions of folfox+avastin. unfortunately, the midway ct scan revealed that there were growths in her liver. so we switched to folfiri+avastin. the idea is to have 3 sessions of the new mix and have a scan and see if the mets shrink enough to make her a resection candidate. she has had 2 sessions already. she started fasting for 2 days leading up to the chemo, but only for one session so far. overall, the side effects are worse than what she experienced in previous sessions (nausea seems to be lasting longer, she is also more tired, pain in the back, basically terrible). her oncologist knows that she will fast before chemo. he is worried that mom might lose weight, which is very undesirable. but we think that if she eats good fats and protein for the rest of the time, the intermittent fasting will not affect her weight too badly. 

i am very uncertain about the benefits of this idea, but as said above, the study results (albeit on mice) sound promising and the logic behind the idea seems plausible.

thxmiker's picture
Posts: 1282
Joined: Oct 2010

I have doe both Folfox and Folfiri w/Avastin.  Both were pretty rough on my body.   The side effects from Folfox are still with me 3 years later.   Folfiri made me violently nauseated. I would lose it every tiem after the third treatment hard.   I would eat about 2 hours before my treatment to lessen the nausea.  This helped but did not end the issue.    I can not even immagine not eating and not having the strength to fight off the other sife effects.  Whom ever wrote the fasting 48 hours before treatment is a MORON!  One would be so depeleted they would be at major health risks.


Best Always,  mike  

steveandnat's picture
Posts: 887
Joined: Sep 2011

I'm with everyone else and eat nowWhitley your appetite  is there. Hopefully the side effects won't be too bad.  Jeff

traci43's picture
Posts: 775
Joined: Jul 2007

Everyone says eat but there have been people (cannot remember who) have fasted before chemo.  I think they started with one day then went to two days.  It seemed to help them with side effects, but I cannot remember if the chemo was more effective.  If you know how to search on this board, you might be able to find it.  I'm sorry, but I don't know how to search.

I've thought about trying it if I go back on FOLFIRI.  I've been doing XELIRI so not sure it would help with the pills.  Good luck and let us know if you do it and how it works for you.  Traci

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Joined: Oct 2009
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