This blog is taken from a webinar hosted by NCIM Cancer Specialist Nutritional Therapist Kirsten Chick, who has spent around two decades providing nutritional support to people with a cancer diagnosis or recovering from cancer.

Kirsten is a cancer survivor herself. She never set out to specialise in this area, but it became the focus of her work. Her aim is for people to feel calmly nourished by their nutritional approach, and in the webinar she set out the fundamentals and answered the questions she is asked most often.

There is no one-size-fits-all cancer diet

Kirsten’s first key message is that no single cancer diet suits everyone. There are many types of cancer, but more importantly there are many different individuals, and nutritional therapy is personalised and focuses on each person’s needs and preferences.

At a first appointment, she asks dozens of questions to build a medical history and to understand who the person is, what their lifestyle is like and what matters to them. She will not tell someone to eat cabbage all day if they do not like it. Food is to be enjoyed, and she wants to keep that joyful element in place!

The diagnosis is part of the picture, but not the whole of it. Kirsten also asks what has happened before, how the body is coping, and even how it is managing the change in the weather.

Most importantly, nutrition sits alongside conventional care, not instead of it. It is not trying to step on the toes of the medical team, but to work with them for a smoother ride for everyone involved. Even when conventional options have come to an end, there are still things that can be done.

Nutrition is a broad path, not a narrow tightrope

One of Kirsten’s favourite messages is that nutrition is a broad path. Too often she sees people arrive at her clinic terrified to eat anything in case it feeds the cancer, ending up on a very restricted, fearful diet.

That fear is itself a stress message to the body, and she explained that we need to feel nourished, supported and grounded for the immune system to work well. There is plenty of wiggle room in a diet. This is not a licence to ignore nutrition altogether, but a way of gently steering towards the middle of the path.

When people feel confident, relaxed and supported, the nervous system settles enough for the rest of the body to function well. There is little point in a perfect plate of food if the nervous system is so dysregulated that digestion and absorption are affected.

Sometimes the diet needs to be restricted temporarily, for example because of digestive issues. Even then, Kirsten sees her job as creating some sense of breadth and wiggle room within it. Kirsten’s number one priority is to help people feel nourished and calm. Certain nutrients and approaches to diet support the nervous system, the adrenals and the wider endocrine system, which helps that sense of feeling grounded and centred.

Nutrition can also help to address symptoms of the disease and side effects of treatment, which is wonderful when it happens. It also offers broader support for:

• the immune system and digestion
• cardiovascular and metabolic health
• detoxification processes in the liver, kidneys and lymph

Every process in the body needs nutrients, and that includes water. All of these systems play a part in overall health and in managing a specific disease, so Kirsten believes it is important that the groundwork is in place.

When to start focusing on nutrition

As soon as possible, Kirsten says, although she accepts that this is not always possible. She recalled a woman waiting for breast test results who put a nutritional plan in place beforehand. When the result came back as cancer, her first thought was whether she had a plan, which helped keep her calm and focused. It is a very different message from the more common “I wish I’d seen you sooner”.

Kirsten is also clear that she never wants to add to someone’s overwhelm. At certain points it may all feel too much, but there are benefits at every stage.

Before treatment

Surgery, chemotherapy and radiotherapy can take a toll, so Kirsten encourages people to think of them like a marathon they are training for. Good nutrition builds strength, vitality and mental resilience.

It is also a crucial time for gut health. Several studies across different cancers suggest outcomes can vary depending on the gut microbiome before treatment, so even a week or two of support is worthwhile. She also pointed to data from the PREHAB trial, in which the prehabilitation group had better body composition, greater muscle strength and more often met protein targets.

During treatment

Nutrition can help manage side effects and support physical and emotional resilience. Kirsten stressed this should be done with someone who knows what they are doing, as many things can interact with chemotherapy, radiotherapy and immunotherapy. The aim is to support treatment, not get in its way.

Weight can go either way. Some people lose weight to a level where muscle wasting, or cachexia, sets in, which is an inflammatory condition. The traditional advice was to eat cakes and sweet drinks to keep weight up, but guidance from sources such as Macmillan and the Royal Surrey Hospital has moved towards protein, other nutrients and appropriate exercise. Kirsten noted that the older advice is still widely heard. Others gain weight, and this too should be managed in a supportive, nutrient-dense way.

Most supplements are not appropriate during most treatments, which is why individual guidance matters. Kirsten tends to keep vitamin D going through treatment, and described a recent study in breast cancer patients that reported a better response to chemotherapy in some groups. It used a high dose, so this is not something to try without professional advice.

When appetite is low

Appetite can drop for many reasons, including treatment, the disease itself, low mood, gut issues and stress. A cancer diagnosis is a trauma, and one of the first things the body does under threat is switch off appetite and digestion to save energy.

In those times, Kirsten recommends keeping things simple and easy to digest:

• have a variety of vegetables across the weeks, rather than in every meal
• try well-cooked or blended soups and smoothies, depending on whether the body is drawn to warm or cool foods
• sip soothing herbal teas, such as ginger tea, which can help with nausea
• keep blood sugar supported and stay hydrated

She also reassured listeners that if a wide range of fruit, vegetables and pulses causes pain or bloating, it is fine to listen to the body and return to them later. She is not anti-sugar or anti-carbohydrate, but suggests including them in ways that nourish and do not spike blood sugar.

After treatment

Recovery can take longer than people are led to expect, physically and emotionally. Surgery is a big event for the body, and chemotherapy, radiotherapy and antibiotics can be life-saving but may batter the gut bacteria, which is why Kirsten supports the gut before and after treatment, and gently during it.

Nutrition can also support:

• sudden early menopause caused by treatment, or menopause symptoms during treatment
• long-term effects of treatment and side effects of ongoing medication such as tamoxifen and letrozole
• the prevention of recurrence, an area where research is growing

Kirsten believes it is never too early or too late to think about nutrition. If you feel you have wobbled off the path, remember it is a broad one, and you can clamber back on at any time.

Listen to and trust your body

Kirsten acknowledged that this is hard when the body feels like it is working against you. Minds can be filled with panic, fear and everyone’s differing opinions, and there is a great deal of conflicting information online, because science keeps learning new things while the old science stays on the internet. This is another reason her main priority is helping people settle and feel grounded, because then it is easier to listen to and trust the body.

Connecting with food and cooking, if there is the energy and resource to do so, is another way of feeling nourished. Kirsten recommends organic food where possible, while recognising that it is not always accessible. Community gardens, food box schemes, vouchers and growers who use organic methods without the certification can all help. Some insecticides and other chemicals can be disruptive to the hormonal and immune systems, but she asks people to weigh up the stress of worrying against the chemical load. Do what you can, draw a line, and be comfortable with it.

Kirsten describes nutrition as anything that nourishes you. That includes food, but also movement, the environment you are in, the people around you and the thoughts you surround yourself with.

The key areas she usually covers are the rainbow diet, protein, beneficial fats and oils, whole grains, hydration and eating patterns. In this webinar she focused on three: the rainbow diet, protein and eating patterns.

The rainbow diet

The colours in plants come from families of nutrients called polyphenols and carotenoids. They play protective roles in the plants and, when we eat them, in us. Examples include anthocyanins in purple berries, curcumin in turmeric, hesperidin in citrus fruit and quercetin in apples and onions. These nutrients are anti-inflammatory and antioxidant, helping to protect tissues and DNA, and many may have anti-cancer benefits. They also feed the gut microbiome, which produces short-chain fatty acids such as butyrate and acetate. These in turn have anti-inflammatory and antioxidant effects, and some are liver-protective or help to regulate blood sugar. Eating a rainbow diet also brings in a variety of fibres that feed the microbiome.

Protein

Protein comes from animal and vegetable sources and is made of amino acids. Animal proteins contain all the amino acids the body needs, while vegetable proteins need to be combined to provide them. For the average person, a typical figure is about 30 grams of protein per meal, which would take around four eggs, so it helps to combine different foods.

Protein matters for the immune system, as antibodies and white blood cells are made from it. It is also important for muscle strength during treatment, when the aim is to build muscle, not lose it. Every cell in the body is partly made of protein. Kirsten and other cancer nutrition professionals often see people not eating enough of it.

A protein-rich breakfast, alongside fibre and polyphenols, helps to support blood sugar throughout the day. That supports the metabolic system, which she describes as key in cancer. Many people find that cravings for sugar and ultra-processed foods melt away, and this is one of her favourite tips.

Eating patterns

A circadian diet follows the natural day and night cycle, with more eating and movement in daylight hours and less in the dark. Kirsten explained that this has implications for digestion, sleep and immunity, and when combined with steady blood sugar it supports energy, memory and mental health. It also forms part of an anti-inflammatory approach to diet.

Common questions: it depends, and how you do it matters

Kirsten is often asked whether dairy, gluten, alcohol or sugar are allowed. The answer is usually “it depends”, or “yes, but think about how”.

• Sugar: not a massive no-no or something to fear. It is about how and when, with small amounts best taken alongside fibre, protein or fat to slow its entry into the bloodstream.
• Alcohol: a known carcinogen, but a glass at Christmas is not going to push anyone over the edge. The question is what it brings to your life, and whether it has become something you depend on, in which case it needs addressing.
• Caffeine: some people do better with less, and not on an empty stomach. Choose good quality coffee to avoid mould.
• Dairy and gluten: very individual.
• Soya: Kirsten said concerns about soya foods and hormone-positive breast cancers have been largely debunked. She is a yes for organic or non-GM soya in food forms such as tofu, tempeh and unsweetened soya milk, but more cautious about concentrated soya isoflavones in supplements.
• Green tea: fine in most situations, at one or two cups a day, as long as it is good quality and does not make you feel nauseous. Some treatments and medications may interact with it, so check if in doubt.
• Desserts and sweet treats: most of the time these stress the metabolic pathways too much, which is a concern when you are recovering from or trying to prevent a metabolic disease such as cancer. Kirsten suggests stepping stones, such as lower-sugar recipes, and says cravings usually fade as blood sugar improves with a protein-rich breakfast. Enjoyment matters, but if food has become an emotional crutch, it is worth asking what else could bring more pleasure and joy into life.
• Probiotics: a controversial topic. Kirsten prefers to support the gut microbiome in other ways, such as medicinal mushrooms, which she says have encouraging evidence for reducing symptoms during chemotherapy and radiotherapy. If neutrophils are low, advice should be individual.
• Breakfast cereals: many granolas look healthy but are high in sugar, and “protein-rich” on a box often is not. Kirsten makes her own muesli with oats, seeds, fruit and a little protein powder, or has eggs, avocado and mushrooms. Savoury soup for breakfast is also common around the world.
• Turmeric: culinary amounts are completely fine during treatment, but concentrated turmeric supplements are worth being wary of.

Which diet should you choose?

People often ask about the Mediterranean, ketogenic, plant-based, raw and paleo diets. Kirsten explained that the choice cannot be made from research alone, because research does not take account of the individual or the climate they live in. She knows people who thrived on a raw vegan diet in Mexico, only to find it a nightmare back in the UK.

If you are unsure, she suggests the Mediterranean diet, which is largely plant-based with some fish and eggs and the occasional piece of organic, grass-fed meat. For specialist diets, she recommends working with someone who can advise properly.

Fasting

There are many types of fasting, and the research is changing all the time. Kirsten is a big fan of intermittent fasting, but the pattern is crucial. She does not recommend doing it by skipping breakfast. Instead, have an early protein-rich breakfast, then lunch and an early supper, and fast overnight from there. A fast of 12 to 14 hours is fine, and there is no need to go longer.

She has had good experiences with people fasting around treatment, including the fasting mimicking diet and cycling a ketogenic diet, but only with proper support. Fasting is completely unsuitable for anyone with an eating disorder or severe weight loss. For those who want to try, she suggests starting with 12 hours overnight.

Dietary priorities

Kirsten summed up the priorities as:

• keeping blood sugar stable
• eating nutrient-rich foods, including a broad range of polyphenols and fibres
• staying hydrated
• steering clear for a while of any foods that flare up digestion or skin problems

As broad as possible, but not necessarily in every meal, as variety across the weeks counts too. The test, she says, is simple: you should feel nourished by your diet, and then you know you are on the right track.

Learn more

Kirsten is available for online nutrition appointments through NCIM. Learn more and book a discovery call here: NCIM Clinical Services

NCIM offers two bite-sized courses by Kirsten on its education website: Breast Cancer Nutrition Foundations, and a focus on nutrition for hormonal breast cancer. Use the code Kirsten25 for 25% discount until 4 November 2026. Each course takes around an hour. Learn more here: NCIM Short Courses Her book, Nutrition Brought to Life, is a general nutrition guide with 50 recipes at the back.

NCIM also runs three in-person metabolic health workshops with Dr Thompson and nutrition expert Claire Cohen throughout the year, covering how to reduce blood sugar spikes and cook delicious alternatives. Places are limited to 15. A free, grant-funded homeopathy service for cancer patients is also available later iin 2026, and you can find out more by emailing [email protected].

The NCIM membership includes access to recordings of all of our webinars. Learn more here: NCIM MEMBERSHIP

This blog offers general information and is not a substitute for personal medical advice. Please speak to your oncology team or a trained healthcare professional who specialises in cancer nutrition, before making changes to your diet or taking supplements.