Nutrition Tips for Managing Cancer Treatment Side Effects

Starting cancer treatment often brings a wave of unknowns. It’s completely natural to feel uneasy - especially around how it might affect your daily life, including your eating habits and nutrition.

But here's some reassuring news - there is so much that can be done to manage side effects and support your wellbeing during this time.

This isn’t just about enduring treatment. It’s about living as well as possible while going through it. Having a practical nutrition plan can offer a sense of control, ease day-to-day challenges, and help support your strength and resilience.

In this blog, we’ll explore practical ways to nourish yourself and manage some of the most common side effects of cancer treatment. These ideas are designed to reduce stress, support your body’s healing, and help you feel more like yourself - one small, manageable step at a time.

The Importance of Nutrition and Physical Activity

Before we explore nutrition tips, it is helpful to remember that both good nutrition and physical activity play important roles in nurturing your resilience during and after cancer treatment.

Gone are the days when the standard advice for cancer patients was simply to rest. Research shows that regular physical activity can help with managing side effects and supporting recovery. Some benefits include:

• Reducing fatigue and bolstering energy levels

• Improving mood and reducing anxiety

• Maintaining muscle strength and bone health

• Strengthening the immune system

• Managing weight changes

• Reducing risk of cancer recurrence for some cancer types

Some days will feel easier than others, and that's completely normal. On more difficult days, be gentle with yourself. What helps is what’s doable - and that might change from day to day. Even small steps can make a meaningful difference.

If you’re unsure where to begin with exercise and movement, my brilliant physiotherapy colleagues have shared practical tips here.

How Good Nutrition Can Help During Treatment

Eating well during treatment can ease side effects, keep your strength up, and support recovery. Even small adjustments can offer a sense of control and help you feel more supported.

The ideas below are based on what I’ve seen help many of my clients. Some might feel helpful for you too. Others might not be right - and that’s okay. If you’re not sure where to start or need something more personalised, I’d be happy to support you.

Practical Nutrition Tips For Common Side Effects

Tips to help with nausea

• Eat little and often: opt for five or six small meals or snacks throughout the day rather than three larger meals.

• Cold or room-temperature foods: may be more appealing as they have much less smell. Consider options like:

  • A bowl of cereal with your preferred milk

  • Hummus with oatcakes, bread sticks, or pitta strips

  • Yoghurt topped with berries and a sprinkle of nuts and seeds

  • A smoothie, sipped slowly

  • Chia seed pudding

• Listen to your body and trust your instincts. Focus on foods that feel manageable in the moment. Many people find that plain foods are easier to tolerate, such as:

  • Dry crackers, oatcakes, rice cakes, breadsticks or toast

  • Porridge

  • Yoghurt with sliced banana or stewed apple

For others, slightly salty or savoury foods can be more appealing, such as:

• Crackers or oatcakes with hummus, tahini, or nut butter

• Toast with Marmite or cream cheese

• Soup or broth with a slice of toast

• Stay hydrated by sipping on fluids between meals. You might find the following options helpful:

  • Herbal teas (hot or cold)

  • Coconut water

  • Vegetable juice

  • Clear soup, broth, miso soup, or stock

• Incorporate ginger, known for its anti-nausea properties:

  • Add freshly grated ginger to porridge, smoothies, jelly or soup

  • Nibble on ginger oatcakes

  • Sip on warm ginger tea

If nausea persists, or you are unable to keep food or fluids down, please speak to your treatment team.

Bolstering your appetite

Loss of appetite is common during cancer treatment. There are lots of ways to help support your nutritional needs:

• Stick to a routine. Your body appreciates consistency. Try to eat something small at regular times.

• Embrace the 'little and often' approach to eating. Use a side plate instead of a dinner plate to avoid feeling overwhelmed. If you're able to have seconds, celebrate it as a win.

• Have nourishing snacks on hand:

  • Overnight oats

  • Egg muffins

  • Wholegrain crackers with nut butter, cheese, or hummus

  • Greek yoghurt with berries

• Identify your best eating time. If morning is best, consider front-loading your day with more substantial meals. Remember, there are no rules - porridge can make a great supper time snack!

• Sip on nourishing fluids throughout the day:

  • Homemade smoothies made with fruits, vegetables, and a dollop of yoghurt

  • Turmeric latte made with your preferred milk

  • Broth or soup

  • Vegetable juice

  • Milky drinks can be enjoyed warm or cold, using your preferred type of milk

Small wins matter - even a few spoonfuls are progress. If appetite loss is affecting your weight or wellbeing, your treatment team may suggest supplement drinks or products, or additional support. I am also here to help.

Navigating taste changes

Taste changes are common during treatment and can affect how enjoyable (or not) food feels. They can also make it hard to get the nourishment you need. If this sounds familiar, here are a few ideas that may help:

• Keep your mouth clean and moist: this can help improve how things taste and feel. Your treatment team might recommend using a soft toothbrush or a specialist mouth rinse, depending on your care plan. Try to avoid mouthwashes containing alcohol, as these can dry out your mouth and make things more uncomfortable. If you notice soreness, dryness, or unusual changes in your mouth, let your treatment team know.

• Experiment with flavours, texture and temperatures:

  Everyone’s preferences are different, and they can change day to day. You might try:

  • Adding different herbs, spices, marinades, or sauces to your meals. Explore distinctive flavours such as pesto, olives, capers, tamari, black olive paste (tapenade), Worcester sauce.

  • Cold or room temperature foods may taste better than hot ones.

  • Explore both crunchy and smooth textures to see what is most appealing.

• Adapt your protein choices: If meat doesn't taste right, try marinating it, or opt for alternative protein sources like fish, eggs, or plant-based proteins such as beans, lentils, or tofu.

• Manage metallic tastes:

  • Use plastic or bamboo cutlery instead of metal.

  • Try cooking in glass or ceramic dishes instead of metal pans.

• Suck on sugar-free mints, pastilles, or other flavoured options to refresh your palate and help eliminate any unpleasant tastes. 

Taste changes can feel frustrating - especially when your appetite’s already low. But with some gentle experimenting, you might find a few options that work better for you.

Supporting a dry mouth

Dry mouth is often misunderstood as a mere inconvenience, but for those experiencing it, especially during cancer treatment, it can severely impact daily life and wellbeing.

Adapt Your Diet:

• Opt for soft, moist foods.

• Add gravies or sauces to dry foods.

• Try foods with high water content, like cucumber, celery, and melon.

• Consider eating frozen fruit or ice lollies if temperature isn't an issue.

• Reduce or avoid caffeine and alcohol, as these can dry your mouth.

• Keep sipping fluids regularly throughout the day. A small stainless steel bottle can be a great companion when you're on the go. Its compact size makes it easy to carry in your bag without adding extra weight, ensuring you always have water or your drink of choice within reach.

Additional Tips:

• Maintain good oral hygiene. Avoid mouthwashes containing alcohol. Many clients have found applying coconut oil inside the mouth helpful; it provides a moist barrier and may have additional antimicrobial benefits.

• Sip water or herbal tea (warm or cold) frequently throughout the day to keep your mouth moist.

• Try sugar-free gum, mints, pastilles, or other flavoured options to help stimulate saliva production.

• Consider trailing dry mouth products available over the counter or on prescription. Some examples include Biotene gel, Oralieve gel, and bioXtra gel. Many clients experiencing dry mouth with have found XyliMelts helpful at night time. Your healthcare team can advise on suitable options.

Tips for easing constipation

Important Note: The following advice is for general constipation related to cancer treatment. If there’s any chance of a blockage - for example, if cancer is affecting your bowel or stomach - or if you’ve had bowel cancer in the past, please speak to your treatment team before making dietary changes. In these situations, you may need a different approach to stay safe and supported.

To promote regular bowel movements:

• Stay well hydrated by drinking plenty of fluids throughout the day. Many people report that starting their day with a warm drink can help stimulate bowel activity.

• Limit sedentary behaviour, such as prolonged sitting. Reducing time spent inactive can help stimulate bowel movements and improve overall digestive health. Even small movements throughout the day, like standing up regularly or doing gentle stretches, can make a difference.

• Gradually increase your fibre intake (to avoid discomfort and bloating) by adding more fruits, vegetables, nuts, seeds, pulses, and whole grains to your diet. It’s also very important to drink plenty of fluids as you increase your fibre intake, as adequate hydration is essential for helping fibre work effectively in your digestive system.

• Research suggests that eating kiwi fruit may help alleviate constipation. You can easily add kiwi to your diet by adding it to yoghurt, cereals smoothies, or enjoying it in salads.

During cancer treatment, there may be times when you need to use stool softeners or laxatives, especially when taking certain medications like painkillers. This is completely normal. Your healthcare team is there to support you - don't hesitate to discuss any concerns about constipation with them.

Managing diarrhoea

Diarrhoea can be a side effect of cancer treatment, but it might also be related to other factors like infection or antibiotics. Understanding what’s causing it can help you find the best way to manage it.

If you’ve been prescribed anti-diarrhoeal medication, it’s important to take it as directed - these are often a key part of managing treatment-related diarrhoea.

Some cancers - such as pancreatic, colorectal, or neuroendocrine tumours (NETs) - can affect digestion more directly, so nutrition advice for these situations may need to be more specific. If you’re unsure whether this applies to you, check with your healthcare team.

Tips to help manage diarrhoea:

• Stay hydrated: Replacing fluid losses is essential.

  • Try sipping water, herbal teas, or lightly flavoured drinks throughout the day.

  • Salty fluids like clear broths, miso soup, or stock can also help, as they provide both fluid and electrolytes.

  • You might find it helpful to add electrolyte drops or powders to your drinks - this can be a simple way to top up minerals like sodium and potassium. Oral rehydration solutions (such as Dioralyte) are also available and may be recommended if you’re experiencing significant fluid loss. If you’re using electrolyte products or rehydration salts, it’s important to follow the instructions on the packaging. Sip slowly and frequently, rather than drinking large amounts all at once.

• Eat smaller, more frequent meals: This can be easier on your digestive system than large meals.

• Listen to your body: While food isn't usually the primary cause of diarrhoea during cancer treatment, pay attention to how different foods affect you. Try foods you fancy in small amounts. Many people find that spicy, fatty, greasy, or fried foods, alcohol, caffeine, and artificial sweeteners (like xylitol or sorbitol) can worsen symptoms.

• Consider fibre intake: While scientific evidence is limited, some people find symptomatic relief by modifying their diet for a day or two. This may include opting for easily digestible foods like stewed apple, banana, natural yoghurt, porridge, plain crackers, smoothies, soups, broths, eggs, fish, chicken, and sweet potato (without the skin). If you notice that high fibre foods seem to worsen symptoms, consider reducing them temporarily. Only do this if it helps and aim to return to a balanced diet that includes fibre as soon as you can.

If symptoms are new or don’t seem to be improving, speak with your treatment team so they can check what’s going on and recommend the right support.

Tips to manage fatigue

Fatigue is an incredibly common side effect of cancer treatment. It can be persistent, lasting not just during treatment but sometimes for a while afterwards.

This type of tiredness often feels very different from everyday fatigue. It doesn’t always improve with rest and can make everyday tasks - like planning meals, shopping, or cooking - feel like climbing a mountain. Many people describe it as feeling like “wading through treacle.”

• Physical activity: There is strong evidence that physical activity can help manage cancer-related fatigue. In fact, it’s one of the most effective strategies we have. Starting slowly with low-intensity exercise is usually safe for most people during treatment. If you’re unsure what’s right for you - especially if you’re dealing with bone disease, lymphoedema, cardiotoxicity, or other concerns - do check with your treatment team first. You can find practical guidance from trusted physiotherapy colleagues here.

• Avoiding the ‘boom and bust’ cycle: You might have days when you feel up to doing it all - socialising, exercising, cleaning, cooking - and then find yourself wiped out the next day. This ‘boom and bust’ cycle is very common. Instead, try to aim for a steady, manageable pace that supports your energy more consistently.

• The 3 P's: Prioritising, Planning, and Pacing. These can be really helpful when fatigue is getting in the way. A few ideas to start with:

  • Prioritising: Focus on what you must do over what you could do. It’s more than okay to say no to some things in order to preserve energy for what truly matters to you. Prioritise what sustains you and aim to limit the things that drain you.

  • Planning: Try planning your trickiest meal of the day - maybe dinner - ahead of time. Stock up on the necessary ingredients so you’re not using precious energy deciding what to eat when you're tired. Additionally, having a few ready-made dishes in the freezer that you can simply take out and warm up can be a big help.

  • Pacing: Think of your day as a series of gentle waves. Alternate activity with rest, and give yourself permission to pause and breathe between tasks.

  These are ideas to support you - not add pressure. Use what helps, and leave the rest.

• Stay hydrated: Even mild dehydration can increase fatigue. Sip water, herbal teas, or your favourite nourishing drinks throughout the day to help keep your energy steady.

• Accept offers of help: This isn’t always easy - but it can make a real difference. Whether it’s someone picking up groceries or walking your dog, small acts of support can ease your day. If you're not sure how to ask or accept help, I’ve written more about it here.

• Check your levels: If fatigue suddenly gets worse, or feels very different from usual, let your treatment team know. They may want to check your haemoglobin, iron, or other markers to see if something else is going on.

Supporting your immune system

A common question is, "What can I eat to boost my immune system?" While no single food can magically 'boost' immunity, a nourishing diet can make a significant difference and supports your body's natural defences. When possible, aim to include a variety of fruits, vegetables, lean proteins, whole grains, and beneficial fats in your meals. Additionally, many of the clients I support benefit from vitamin D supplementation. 

If side effects are making it hard to eat well, we can work together to gently support your immune system with a personalised approach.

You can also download my free ebook: 10 Tips to Bolster Your Immune System During and After Treatment.

You Don’t Have to Figure This Out Alone

Navigating nutrition during cancer treatment can feel complicated - but you are not alone in this. Many of my clients tell me they just want to know they’re doing the right thing. I’m here to help.

Together, we can:

• Ease food-related stress and side effects

• Find foods that work for your body and needs

• Tailor strategies to your energy, symptoms, and preferences

📩 info@thecancerdietitian.com

☎️ 020 8064 2865

💻 Book an appointment

The content provided in this blog is for informational purposes only and should not be considered personalised nutrition, dietetic, or medical advice. Please consult your healthcare team for personalised advice and guidance regarding your specific medical condition or dietary needs.