Fasting and Chemo

Hey all!

Hope you all had a great Halloween!

I have been doing a lot of reading in preparation for Chemo and came across some interesting research that indicates that a short period of fasting can increase the effectiveness of the chemo and decrease the impact of potential side effect! The science behind it looks sound to me and focuses on putting your healthy cells into slow mode, a mode that cancer cells do not have therefore making them (the cancer cells) more susceptible to the chemo! Has anyone heard of anyone giving this a go?


11 Replies

  • HI D I have read something about this somewhere that if you fast, the chemo is more effective but I dont know how true it actually is. Some of us wouldnt eat a whole lot the days after chemo when you think about it anyhow. I would say the Jury is out on that one

  • Do you have any reputable sources?

  • Have to agree with Suzuki. Not many of us feel like eating much when we have had Chemo.

  • Hello. Yes this seems to be the latest talk. A friend who is a dietician mentioned this to me and said that the 5/2 diet could be good. I discussed it with my oncologist who seemed quite concerned the fact i have lost a stone and a half anyway after 4 chemos and op. He was more concerned about weight loss caused by chemo and i have to agree. If you have a few extra pounds that you can lose then i would say go for it. Unfortunately i don't and therefore planned fasting is not for me. I am now trying to put weight on which is involving lots of dairy and not so healthy food which does concern me but not feeling the health food and juicing at the moment.

  • Hello All!

    Thanks for the responses! I have just witnessed my sister going through Chemo so I know where you are all coming from regarding the difficulty eating!! Hawk86 the main research centres on a large study published in Scientific America but there are other peer reviewed studies aswell. The large studies seem to focus on animals but there are smaller studies looking at humans. I am from a scientific background and studied Nutrition for a short time in college so I tend to come at these things with a very critical mind, this research seems to make sense to me and that's why I was curious! Leeds2015 at this point in time I have had one surgery with another due on the 19th I can definitely afford to lose some lbs so I am thinking I might have a chat with my oncologist about it and see what he says. I am seeing him tomorrow for a questions and answers session and I have just added this to the list! I will let you know what he says just for your own curiosity!


  • Just want to add my little bit on this topic. I recall that when I was getting Chemo 4 years ago my team wanted me to maintain my weight as your chemo dose is based on your weight. If you are too thin they can only give you a smaller dose. It may be totally behind the times when it comes to present day science but it made sense to me at the time. However I took them at their word beyond the end of my treatment so now I have trouble getting rid if it ! In any case I would be interested to know what your oncologist thinks. Good luck with everything . I have my last check up for 6 months the day before


  • I have read that the thinner you are before and after chemo the better for you. I'm sure that is within a healthy limit though. I personally gained 10 pounds during chemo because of the steroids, I would guess. Plus I was so ill, I thought I needed to eat as well as I could to keep up my strength. I lost 20 pounds after chemo on purpose because I heard it was good to be thin. I have since gained 7 of those back and although I try, can't seem to get rid of it. I am still trying.

  • Thanks for asking the question as you've prompted me to start planning.

    I'm starting chemo again in a couple of weeks and will approach it with some sort of fasting regime (not quite worked out what yet, three days before and one after crops up, low carb and low sugar, but may do 4:3 or something).

    I first came across this idea a couple of years ago, when on chemo, when my sister-in-law mentioned that it was mentioned in the 5:2 diet book. The middle of chemo wasn't the point to look into it!

    But I did the read the book afterwards and became an enthusiastic 5:2 dieter. I've lost 11 kg since I started (between second and soon to be third line) and am now no longer (according to the NHS calculator) technically overweight and feel good about being back in the zone I was in when younger.

    There seems to be quite a lot of research going on into this area in the States. With some quite interesting results. Not just in relation to the effectiveness of the chemo but in relation to reported side effects.

    Here's a link with more references:

    I don't think it would be a good idea to start doing this just for chemo or immediately before. You need to feel confident you can cope with intermittent fasting and/or calorie restriction (some will be helped in this by their religious practices). And it certainly wouldn't be a good idea if you have a good diet but have difficulty staying at a healthy weight. Or, without a lot of thought, if you tend to lose weight on chemo. I've tended to put it on during chemo.

    Food for thought ( ho ho ho ) as they say!

  • I have heard that those who reduce their calories fair better when doing chemo. Also reducing calories are helpful to keep the cancer away afterwards. You have to keep up your strength though so you must eat healthy.

  • Hi D.Dont know if this helps or not.My last chemo session I had been fasting as I was having a Pet scan in the afternoon,after chemo.Since I restarted chemo in August,I kept having pain on my right side,a suspicious lymph node! After the last chemo,no pain anywhere! So don't know if it's the chemo that's working or that it was the fasting pre chemo that made the drug work better,

  • Thanks for all the comments ladies! I have decided that I am going to give it a try, I am not going to be stupid about it but I am going to give it a try! Waiting on a date now for my Chemo! Second surgery Thursday week so Chemo about 3 weeks later! The next few months are going to be fun........NOT....... but dya know what as Buzz Lightyear so aptly put it Onwards and infinity and beyond!!!!!

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