In focus: diet - intermittent fasting

[OvacomeSupport]

Hello All

This month in our ‘Health in Focus’ posts, we’re looking at diet. Often, people diagnosed with cancer make changes to their diet because they want to support their health. In these posts, we’re looking at some of the types of food that we are asked about on the support service, whether to eliminate or reduce consumption and the evidence around this.

In this post, we’ll be looking at intermittent fasting, which is another way of eating that many people explore when they want to support their health through their diet. There are a number of different intermittent fasting programmes, but they all involve drastically reducing (or stopping) intake of calories for a defined period of time.

If you're considering making any significant changes to your diet, it's important to get medical advice as to whether this is appropriate for you at this time.

Examples include consuming no calories for 12 or more hours per day and eating normally for the rest of the day or reducing intake of calories to a fraction of normal on alternate days or two days per week (as in the well-known ‘5:2’ diet) and eating normally on the other days. You can find more information about these plans at nhs.uk/news/obesity/alterna... and nhs.uk/live-well/healthy-we...

The theory behind these approaches is that our bodies evolved over thousands of years to survive periods when food was scarce. Our early ancestors evolved to go into ‘growth’ mode when food was available and ‘repair’ mode during times of scarcity. Our bodies haven’t yet ‘caught up’ to life in a world where food is always available.

The theory suggests that if we eat enough calories to stay in ‘growth’ mode all the time, it doesn’t give our bodies time to rest and repair, which isn’t the best way for us to stay healthy. So far, most of the evidence for this comes from research done in animals, for example nhs.uk/news/food-and-diet/n... and nhs.uk/news/diabetes/fastin...

With regard to cancer risk, one theory is that ‘repair’ mode involves both slowing the rate at which our cells multiply and finding and destroying damaged cells that could otherwise develop into a tumour. So far, most of the evidence for this approach has come from animal studies or looking at test results in humans rather than actual health outcomes and it hasn’t been conclusively demonstrated in humans that fasting reduces cancer risk.

For people undergoing cancer treatment, there is also a theory that fasting around the time of receiving chemotherapy can help to reduce some of the side effects. Again, this is based on the idea that our bodies go into ‘repair mode’ when calorie intake is restricted.

Chemotherapy works by damaging cells that are dividing, causing them to die. This includes cancer cells, which are multiplying out of control, but also other rapidly-dividing cells including those in the hair follicles and the lining of the digestive system, causing side effects including hair loss and diarrhoea. The theory suggests that if the healthy cells are in repair mode and not dividing quickly, they can escape some of the effects of chemotherapy, while the cancer cells can’t slow down and so are still damaged. For example, a study found that the white blood cells of mice injected with chemotherapy recovered more quickly when the mice were fasted beforehand (nhs.uk/news/food-and-diet/5...

Some people have found that the side effects of chemotherapy are less severe when they are fasting, but the research into this is at an early stage and the effects in humans haven’t been confirmed. The journalist Decca Aitkenhead wrote about her experiences of chemotherapy, including fasting, at theguardian.com/society/201...

Following some preliminary favourable evidence, a larger-scale research study is currently in progress in Germany looking into the effects of short-term fasting alongside chemotherapy for people with breast and ovarian cancer (clinicaltrials.gov/ct2/show.... The trial is expected to complete in 2022, and some interim results may be published in the meantime.

As we mentioned in our previous posts, the general advice for people diagnosed with cancer is to follow a healthy, balanced diet. The NHS has produced its ‘Eatwell’ guide to show what this includes and in what proportions. You can find the Eatwell guide at nhs.uk/live-well/eat-well/t...

Making large changes to the number of calories we consume can also affect our intake of the nutrients that we need to maintain our health. If you are going to reduce the amount that you eat, it’s important to make sure that you’re drinking enough water and getting the carbohydrates, proteins, fats and other nutrients that you need. In particular, when you’re having chemotherapy you may experience difficulty eating due to nausea, taste changes or mouth ulcers, for example, and it’s important to maintain your weight.

As we mentioned in our first post, research hasn’t established a conclusive link between any particular food or diet and the risk of ovarian cancer (wcrf.org/dietandcancer/ovar... ). Again, if you’re considering any significant dietary change, it’s important to seek medical advice as to whether it’s safe for you.

If you would like to share your experiences of diet following an ovarian cancer diagnosis or have any tips on it, please comment on this post. If you would like information or support, please contact our Support Line on 07503 682 311 or 0800 008 7054 or email [e-mail].

Best wishes

Julia & Anna

Ovacome Support

[Ruebacelle]

Thank you for this. Also theink to the ongiing german trial. I started taxol weekly in june and lractice light fasting 24 hrs before and acter chemo. This means no solids or sugars herb teas water vegetable consommé glass of soy milk and it definitely helped lessen side effects and the pet results were much better than we hoped.

[OvacomeSupport Partner My Ovacome Team in reply to Ruebacelle]

Hello Ruebacelle

Thank you for sharing your experience.

Best wishes

Anna

Ovacome Support

[lesleysage]

When I was on chemos 9 and 7 years ago, I just ate what I could manage and became aware that for the four days immediately after chemo I couldn't manage very much. A dietician did a calorie count of three different days during my 'dose-dense regime' cycle, one in the immediate post-chemo days, one on day 5or 6 and then one in my 'respite week'. What my body could cope with was, respectively, 800 calories per day, 1,200-1,400 calories per day and for the respite week (just one in four), I could happily enjoy 1,600-1,800 calories!

Without some special supplements prescribed by my GP, I would have lost a lot more weight.

Interesting research. Thank you.

[OvacomeSupport Partner My Ovacome Team in reply to lesleysage]

Hello Lesley

Thank you for explaining how you managed eating during chemo, it's very helpful.

Best wishes

Anna

Ovacome Support

[girakoch]

Professor Valter Longo has done a lot of research on intermittent fasting. Read his book

'The Longevity Diet' where he explains the science.

[OvacomeSupport Partner My Ovacome Team in reply to girakoch]

Hello girakoch

Thank you for sharing this information.

Best wishes

Anna

Ovacome Support

[Newbie_2020]

I am on a 18 hrs intermittent fasting daily regime. Last meal at 18:00 and I won't eat till the following day at lunch time. I have water and black coffee when I get up. During fast time, herbal teas (with no added milk, sugar, or even honey and/or sweeteners) are also permissible as they help with flushing toxins out of the body. I normally have chamomile, fennels, mint, aniseeds, licorice, and dandelion. They can be taken separately or can be mixed. I also do the occasional 24hrs fast by having only one meal. This has been helpful during chemo.

For anyone who'd want to start on intermittent fasting, it is best to take it gradually, starting with a 12hrs gap between meals. Gradually reducing the quantities of food intake also help and always be well hydrated.