Eating well during and after cancer

Expert reviewer, Cecilia Jaarsma, Dietitian, Cromwell Hospital
Next review due February 2023

Eating well is important for everyone – and especially so if you have cancer. Having cancer and treatments like chemotherapy can make eating more difficult. Cancer also affects the way your body uses nutrients, which can cause you to lose weight more easily. Eating and drinking well will help you to maintain a healthy weight, allowing you to cope with your cancer treatments better and recover faster.

An image showing a family having lunch

Why is your diet important if you have cancer?

Many people find that they unintentionally lose weight when they have cancer. This can make it harder for your body to cope with the cancer and any treatments you’re having. Eating well helps to keep your strength and energy up, allowing you to manage your cancer and treatments better. It also reduces your risk of infections and other complications, and helps you to recover more quickly.

Cancer affects how your body uses and processes food. So even if you are eating, you may still lose weight or not get the nutrients you need. This is why many people have already lost weight before being diagnosed with cancer.

Difficulties eating during cancer

Having cancer, and treatments like chemotherapy and radiotherapy can make eating difficult for a number of reasons.

  • You might lose your appetite and not feel like eating.
  • If you’re feeling anxious or low, this can put you off eating.
  • You might find food shopping and cooking difficult if you’re not feeling well, are very tired or have lots of hospital appointments to attend.
  • Treatment side-effects, such as feeling sick, mouth ulcers and a dry or sore mouth can make it hard to eat and drink as much as you need to.
  • Chemotherapy can change your sense of taste and smell, which might put you off eating.
  • Radiotherapy and chemotherapy can cause digestive problems like diarrhoea or constipation, and you may need to change your diet to help control this.

What to eat during cancer treatment

Eating well means having a range of foods to get all the nutrients and fibre your body needs. The five main food groups are:

  • fruit and vegetables
  • starchy foods including bread, pasta, rice and potatoes
  • dairy and alternatives
  • meat, fish, eggs, beans and other sources of protein
  • oils and spreads

If you have cancer, it’s common not to get enough energy (calories) and protein in your diet. Protein is important for healing and for your immune system (the system that protects your body and fights off harmful invaders). You need more protein if you have cancer. Protein-rich foods include meat, fish, eggs and beans. You should also make sure you’re drinking enough fluids so you don’t get dehydrated. This is particularly important if you have vomiting or diarrhoea due to cancer treatment.

To get the extra calories and protein you need, you might need to eat a diet that wouldn’t normally be recommended when you’re in good health. This might mean choosing high-calorie and high-fat options when you can, such as full-fat milk or cream, cheese, yoghurts and plenty of butter. Try topping your vegetables with butter or cheese, adding mayonnaise to sandwiches, making milky drinks and adding sugar to breakfast cereals and puddings.

If you’re struggling to put weight on or with any aspect of your diet, you should ask for help from a dietitian. For more information, see the section: Getting help with your diet below.

What foods to avoid during cancer treatment

If you’re losing too much weight, try to avoid foods that provide little energy or nutrients – such as low-calorie drinks, salads and clear soups. These will fill you up without giving your body the calories and protein it needs.

You might find you need to avoid certain foods because of side-effects you’re having during treatment. For example, if you have a sore mouth, you might want to avoid spicy foods. Sometimes, if your immunity is low (for instance, if you’ve had high-dose chemotherapy), you may need to avoid certain foods that could cause infection. These include mould-ripened cheese and cheese made from unpasteurised milk, raw meat and seafood, runny eggs and fresh salad. Your nurse will go through this with you.

Check with your doctor or nurse before drinking alcohol if you’re having treatment for cancer. A few chemotherapy drugs are affected by alcohol – their side-effects might be worse if you drink. Alcohol also irritates the lining of your mouth, so it’s best avoided if you have sores caused by cancer treatment. If you do drink alcohol, don’t drink to excess.

You can read more about particular foods to avoid in our section: Tips for eating with cancer, below.

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Tips for eating with cancer

If you find that your cancer has affected your appetite or ability to eat, there are many things you can try to help.

If you’re tired:

  • eat what you want, when you feel like it – you don’t have to stick to set mealtimes
  • try to plan ahead – if you can, batch cook when you have more energy and fill up your freezer with home-cooked meals to use when you’re tired
  • ask for help from friends and relatives with shopping or preparing food
  • stock up on convenience foods that are quick to prepare or buy nutritious ready meals, or home-delivered food

If you don’t have an appetite:

  • eat little and often – instead of eating three large meals, try eating smaller, calorie- and protein-rich meals or snacks every two or three hours
  • keep small, high-calorie snacks handy for when you feel like eating – good choices include yoghurt, cereal, cheese and crackers
  • when you do eat, try to go for high-calorie and high-protein foods to build up your nutrient stores– try adding cream, cheese, butter or honey to meals
  • if you find your appetite changes throughout the day, eat your biggest meal when you feel most hungry – even if that means eating a big meal in the morning when you’d usually have a small breakfast, for instance
  • blend nutritious smoothies with fresh fruit, yoghurt and ice cream to sip when you can’t face a meal
  • getting some gentle exercise and/or some fresh air before you eat may increase your appetite
  • try to eat well during your ‘good’ periods, even if you find you can’t eat so well immediately after your treatment

If you feel sick:

  • avoid fried and fatty foods and those with a strong smell – try bland food like crackers or plain toast
  • try eating foods or drinks that contain ginger, such as a ginger biscuit or ginger tea
  • sipping on cold, sweet or fizzy drinks may help
  • don’t lie down after eating – stay sitting upright for a short time after your meal
  • try eating meals at room temperature and keeping foods and drinks covered – this might help to tone down any smells that might be putting you off your food
  • have drinks in between meals – but try not to drink a lot just before you eat

If your tastes have changed:

  • eat more of the foods that do still taste good and keep trying those that don’t – your tastes may change again
  • you might find you prefer stronger flavours – try adding herbs, spices, garlic or lemon juice to your food, or go for stronger versions of foods you normally enjoy
  • you might find you prefer foods at room temperature rather than hot
  • if you’ve gone off tea or coffee, try lemon tea or cold fizzy drinks
  • if you have a metallic taste in your mouth, try using plastic cutlery

If your mouth is sore or dry, or you have trouble swallowing:

  • drink plenty of fluids, even if it’s just a few sips at a time
  • try sucking ice cubes or lollies made out of fresh fruit juice
  • blend foods so that they are easier to swallow (or finely chop if you prefer to still have some texture)
  • for savoury meals, try soups, stews, dahls and mince-based meat dishes with a lot of sauce or gravy
  • choose soft desserts, including rice pudding, ice cream, mousses and jellies – add cream or ice-cream if you need extra calories
  • avoid foods with a rough texture or that need a lot of chewing, like toast, raw vegetables and tough meat
  • you may find that spicy, salty and sharp-tasting foods make it worse and are best avoided

If you notice any difficulties with eating and drinking, discuss it with your doctor, dietitian or nurse to make sure you’re getting the right support. They’ll be able to give you lots of support and advice to help.

Can vitamin and mineral supplements help during cancer?

There’s no reliable evidence that taking vitamin and mineral supplements can cure, prevent or control cancer. But they may be helpful for some people with cancer to take alongside treatment. For example, osteoporosis can be a side-effect of treatment for prostate cancer and breast cancer. So if you have one of these types of cancer, you may need to take calcium and vitamin D supplements to help prevent osteoporosis. Your doctor may also prescribe a multivitamin if you’re finding it hard to get all the nutrients you need from your food.

If you’re thinking of taking a supplement, it’s important to speak to one of your healthcare team first. This is because advice on supplements can differ depending on which treatment you’re having. It’s possible that certain vitamins and minerals might affect how some cancer treatments work. Your doctor, nurse or dietitian can give you advice on your diet and exactly what supplements (if any) might be suitable for you.

Getting help with your diet

If side-effects from your treatment are making it difficult for you to eat and drink, speak to your doctor. They can give you advice and prescribe medicines to help you cope. These include anti-sickness medicines and artificial saliva, which can help to combat dry mouth. Your doctor can also refer you to a dietitian if you need some extra help.

A dietitian can provide advice that’s tailored to you, taking into account how you’ve responded to treatment, as well as your lifestyle and commitments. They’ll consider if there’s anything you can do to boost your calorie intake and get more nutrients into your diet. They may also suggest trying food supplements to add extra energy and protein to your diet. These products don’t replace food, but may be useful if you’re not getting enough calories and protein from food alone. They come as a powder that you make up as a drink or add to food. You can buy some types from a pharmacy, and for others, your doctor or dietitian may give you a prescription.

If your doctor, nurse or dietitian thinks you’re still not getting enough nutrients from your diet after trying these measures, they might suggest artificial nutrition. This means having a tube into your stomach or a vein, to supply you with all the nutrients you need. Your doctor, nurse or dietitian will discuss this with you if they feel it might be of benefit.

Diet myths

There’s a lot of information out there about different diets that claim to treat cancer or stop it from coming back. Diets such as Gerson therapy, the macrobiotic diet, the raw food diet and the paleo diet have all been mentioned in the media. But there’s no proof that any of these approaches can help to prevent, treat or cure cancer. Some can even do harm because you won’t get all the nutrients you need to keep healthy.

There’s also ongoing research around the possible link between sugar and cancer. Sugar is a type of carbohydrate that our body uses for energy. There’s been speculation that sugar may ‘feed’ cancer cells – and so cutting it out could help stop cancers growing. Unfortunately, it’s not as simple as this. There seem to be several different ways in which sugar affects cancer risk, but more research is needed before we know for sure.

It’s generally a good idea to limit how much sugar you have as part of a healthy, balanced diet. Eating lots of sugary foods can lead to weight gain, which is a known risk factor for cancer. But this doesn’t mean you should cut down on other types of carbohydrate such as starchy foods like bread, potatoes and pasta. This won’t help with keeping your strength up. Following any restrictive diet can also make you feel stressed and anxious, which won’t help with your recovery.

The best thing you can do to keep healthy is to follow a healthy, balanced diet, that’s been tailored to your needs.

Your diet after cancer

Getting back to normal

Many of the problems you may have had with eating during your cancer treatment will improve once you finish treatment. However, some effects last for much longer. You may, for example, find that things no longer taste the same. The types of problem and how long they last depend on the type of cancer and treatment you had. Speak to your doctor, nurse or dietitian if you’re having problems.

Stopping cancer coming back

Many people want to know what they should eat to help stop their cancer from coming back. There isn’t enough evidence to make specific recommendations about what people should eat to prevent a certain type of cancer coming back. In general, it’s best to eat a healthy, balanced diet, keep to a healthy weight and get regular physical activity. This combination of factors is likely to have the biggest impact.

Losing excess weight

You might find that you’ve put weight on during cancer treatment. This could be for a number of reasons – some cancer treatments, like chemotherapy and hormone therapy, can cause weight gain. You may have been less active than normal or overeaten if you’ve been feeling low. Don’t be too hard on yourself – you’ll probably want to take some time to recover before you think about losing weight.

If you notice your weight creeping up after you’ve finished treatment, it might be the ideal time to start thinking about your diet and lifestyle. If you need to lose weight, it’s important that you do so safely. This involves losing weight gradually and focusing on both diet and physical activity levels. If you’re having hormonal therapy and you think this may be contributing to weight gain, discuss this with your cancer doctor or nurse. It’s important not to stop taking the therapy.

For more information on staying healthy and well after cancer treatment, speak to your doctor, nurse or dietitian and always follow their advice.

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Related information

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  • Reviewed by Pippa Coulter, Freelance Health Editor, February 2020
    Expert reviewer, Cecilia Jaarsma, Dietitian, Cromwell Hospital
    Next review due February 2023