Since Blog 7, when I posted three emerging principles of Fasting for Chemo, a few people have asked me to explain in a bit more detail the thinking behind the first principle: 350 calories-a-day for six days.

So, I thought today it would be useful to discuss this with you and provide links to the papers that informed the decisions I have taken over the past few months.

Please check out Further Reading for references.

Medical Advice:

From the outset I told my doctor at the Royal Marsden that I was fasting for chemotherapy, and their attitude was that, whilst there is some evidence to suggest fasting might help, it is not Royal Marsden policy to support fasting and so, as long as I was getting a well-balanced diet overall, I was to do whatever I needed to do to get through treatment.

I should also confess at this point, however, that I have had medical and scientific input from someone close to me who is not only a medical doctor, but who also has a PhD in molecular biology. My approach is therefore supported not only by emerging scientific research, but is also informed by a medical professional who knows and understands my personal situation.

Why 350 Calories-a-day?

Fasting has been shown to be an effective way of lengthening life span, reducing cell damage, enhancing stress resistance and delaying  aging and age-associated illnesses such as cancer in various species, including mice, rats, and non- human primates (McCay et al, 1935; Weindruch et al, 1986; Masoro, 1995; and Colman, 2009).

Moreover, a large cohort study with over 2000 participants investigated the safety of fasting in patients with chronic disease (Michalsen et al., 2005). In this study, the authors determined that eating 350 calories a day was safe and considered by many of the participating subjects to be beneficial to their illness.

Why Fast for Two days or 48 hours Prior to Chemotherapy?

Until recently these two aspects had not been brought together and tested in humans, but in 2009 a small study was carried out with 10 humans with a range of cancers who voluntarily fasted for a total of 48 to 140 hours prior to and/or 5 to 56 hours following chemotherapy. They reported a reduction in common chemotherapy-associated side-effects such as vomiting, diarrhoea and fatigue. Significantly, there was no evidence that fasting protected tumours or reduced the efficacy of chemotherapy. The authors note that their work is not meant to establish practice guidelines for patients undergoing chemotherapy but that only controlled-randomized clinical trials will determine the effect of fasting on clinical outcomes including quality of life and therapeutic index (Safdie et al.,2009).

Using previous studies and my personal medical advisor to guide me, I decided to fast for 48 hours prior to treatment, which not only seemed to be a realistic fast duration but also allowed the body sufficient time to enter a state of ketosis, which is the aim of fasting for chemotherapy.

Why Fast for Four days after Chemotherapy?

The treatment path I followed initially was four sessions of EC Chemotherapy, which comprises two medications: Epirubicin and Cyclophosphamide. The half life (or time it takes for half of the drug to leave your body) of Epirubicin is approximately 30-40 hours and the half-life of Cyclophosphamide is approximately 3-23 hours although results vary between individuals depending on their age and health.

Based on this information, fasting for four days or 96 hours after treatment seemed like a good way of ensuring my body had cleared as much of the drug as possible without restricting my diet for too long, which may have other unforeseen consequences.

A Flexible Approach

When I started this blog I was undergoing EC Chemotherapy and I had planned to eat 350 calories for two days prior and two days after chemotherapy, increasing to 500 calories for a final two days. But, after experiencing more extreme side effects when I increased my calorie intake, I decided to keep calorie consumption at 350 for six days for the duration of my EC Chemotherapy programme.

I have now finished my EC Chemotherapy regime and have started Taxol, which has a much quicker clearance rate, indeed, 50% of the drug Taxol is excreted between 3 and 51 hours after treatment, depending on the individual’s overall health.  After my last treatment on 1^st October, I was prepared to fast for the full four days as usual, but by day three I felt ready to eat again. So, I broke fast 24 hours early and, with the exception of a bout of nausea, I am eating normally which, compared to previous treatments, is very early in the cycle.

Based on this personal experience, if you are considering fasting for chemotherapy, you might consider checking the clearance rate of the chemotherapy medication(s) you are taking and adjust your fast time accordingly.

Randomised Trials Needed

Whilst there is emerging evidence in this interesting field, it is abundantly clear that large scale, controlled and randomised trials are required. There has been encouraging news in 2018 that fasting can improve quality of life and reduce fatigue but clinical trials are ongoing.

Della x

Disclaimer

The information contained in this post or any other post on this blog is based on personal experience and should not be viewed in any way as medical or other advice. If you are considering fasting for chemo, please consult your healthcare provider.

Copyright © 2015 Johnson