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Eating well during cancer treatment – a detailed guide

Read our guide below which covers advice on how to eat well during cancer treatment.

You can also download a PDF version of this patient information by following the link on the right.

The information is for you if you’re:

  • currently having cancer treatment
  • starting cancer treatment soon.

Why is it important to eat well during cancer treatment?

Cancer treatments disrupt the way cancer cells grow and divide but they can also affect normal cells. This can cause you to feel unwell. It’s important for you to have a healthy, balanced diet during your treatment to stay as well as possible.

Why is it important to keep a stable weight during cancer treatment?

Research has shown that people who maintain a stable weight through cancer treatment live longer and have a better quality of life. It’s important to try not to lose weight during
your cancer treatment.

You’re more likely to lose muscle than fat. This puts you at risk of poor mobility and may reduce your ability to do things that you enjoy.

You may be more at risk of side effects, and your treatment may have to be delayed if you are not well enough

Read more below about what you should eat if you’re losing weight or struggling to eat well.

If you’re on long term hormonal treatment and you’re gaining weight

It may be appropriate to try to lose some weight. See below for information about what you should I do if you
gain weight during your cancer treatment?

If you’re not sure if this is relevant to you, talk to your healthcare professional.

When should I follow a healthy eating diet?

You should do this if you:

  • don’t cope well with treatment
  • don’t have side effects or symptoms that affect your food intake
  • haven’t lost weight
  • have gained weight during treatment.

If you manage well with your cancer treatment, don’t have problems with eating and don’t have a poor appetite, you should aim to have a healthy, balanced diet and keep your
weight stable.

Your diet should include a selection of foods from each food group including:

  • fruit and vegetables
  • starchy foods (carbohydrates), for example, wholegrain bread, pasta, rice and cereals
  • protein – rich foods, for example, beans, pulses, fish, lean meat and eggs
  • dairy foods and alternatives, for example, calcium fortified soya products
  • good quality fats from vegetable sources, for example, olive and rapeseed oil, nuts and seeds.

You should limit ultra processed foods should as they’re generally:

  • higher in sugar or higher in saturated (animal) fats
  • low in other essential nutrients, for example, vitamins, minerals and fibre.

You should limit these if you have a good appetite. These foods can provide a large amount of energy (calories) which can cause weight gain.

Using the eatwell guide

The eatwell guide diagram produced by the Government shows the recommended proportions to include in your diet for each of the different food groups.

It shows how to eat over the course of a few days, not just one meal. By choosing a variety of foods from each group, you will be consuming a wide range of
nutrients to help you to stay healthy through your treatment.

Important tips for a healthy lifestyle

You should follow the tips below to help you lead a healthy lifestyle.

Eat at least 5 portions of different fruit and vegetables each day

1 portion is equivalent to approximately 80g fruit or vegetables. Fruit juices and smoothies only count as a maximum of 1 portion per day due to their high ‘free’ sugar content and
reduced fibre content.

Include starchy carbohydrates in each meal

For example, rice, bread, pasta, potatoes. Try to choose wholegrain options where possible as these are a good source of fibre.

Include protein in your diet, for example, pulses, fish, eggs, meat, poultry and vegetarian alternatives like tofu and Quorn®.

Try to increase the amount of pulses (beans, peas and lentils) in your diet

They’re high in fibre and protein, as well as vitamins and minerals. These provide a good alternative to meat as they’re low in fat.

Have 2 portions of fish per week, one of which should be oily

For example, salmon, mackerel, herring, tuna steak.

Include dairy or dairy alternatives

For example, soya products or other plant based dairy alternatives and fish with bones. They provide calcium and other important vitamins and minerals.

Choose unsaturated (vegetable) oils and spreads

These include olive or rapeseed oils, avocado, nuts and seeds. Consume these in small amounts as they’re high in calories.

Only consume foods high in fat, salt and sugar in small amounts and as a treat

No more than 5% of your total daily energy intake should come from added or ‘free’ sugars. This is equivalent to a maximum of 9 tsp sugar per day for men and 6 tsp
sugar per day for women.

Drink approx 8 cups or glasses of fluid per day

This can include water, low calorie squash, tea and coffee. You should limit fruit juices to 150ml maximum per day due to the high ‘free’ sugar content. Avoid drinks containing added sugar such as high juice and non diet versions of fizzy drinks.

Try to eat at regular mealtimes

This can help you to avoid feeling very hungry and overindulging or reaching for high fat / sugar items.

Try to save alcohol for celebrations rather than regular consumption

Alcohol is high in calories and can lead to weight gain. It’s also linked to an increased risk of some cancers. If you choose to drink, don’t exceed 14 units of alcohol per week (for
men and women). Try to have at least 2 alcohol free days per week.

Try to stay as active as possible during treatment

Research has shown that moderate exercise during cancer treatment is safe and can have many benefits. Aim to be active for at least 150 minutes each week and sit less. Physical activity is anything that gets you moving – it doesn’t have to mean going to the gym!

There are some recommended Macmillan resources below which you may find helpful.

What should I do if I’m gaining weight during my cancer treatment?

If you start to gain weight once your treatment starts, aim to follow a healthy, balanced diet. You might find the following tips useful.

Plan ahead

Avoid buying high calorie foods. If they’re not in the house, you won’t be so tempted!

Watch portion sizes at mealtimes

Using a smaller plate may help.

Fill half your plate with vegetables or salad at your main meal.

Choose wholegrain varieties of starchy foods

This includes pasta, rice, and bread. These high fibre options contain more nutrients and will keep you full for longer, helping with weight management and blood sugar control.

Try to avoid snacks between meals

If you’re hungry, choose healthy options such as a piece of fruit or small handful of plain, unsalted nuts.

Stay active, move more and sit less

Aim to be active for at least 150 minutes per week. Physical activity is anything that gets you moving – it doesn’t have to mean going to
the gym!

What should I do if I’m losing weight or struggling to eat well?

When you have cancer treatment you should aim to stay a stable weight. If you’re losing weight you may need to make some changes to your diet.

If your appetite is reduced during cancer treatment, read our information about eating well with a small appetite. It provides practical support and ideas to help you to
increase the energy (calorie) and protein content of your diet, aiming to prevent weight loss and maintain your energy levels.

If you’re still losing weight, ask your doctor or specialist nurse to refer you to the Macmillan Specialist Dietitians.

What can I do to manage symptoms that affect how I’m eating?

There are a number of side effects of cancer treatment which may lead to nutritional problems, including:

  • tiredness / fatigue
  • poor appetite
  • feeling sick (nausea) and vomiting
  • swallowing difficulties
  • dry mouth
  • sore mouth / ulcers in the mouth
  • taste changes
  • feeling full too quickly
  • diarrhoea
  • constipation.

If you’re struggling with any of the above side effects of cancer treatment, talk to your doctor or nurse specialist about the best way to manage your symptoms medically

Read our information about common nutritional problems and cancer.

For more detailed information, read our information about managing taste changes.

Read our information about mouthcare for patients undergoing cancer treatment.

If you have ongoing problems with poor appetite and unintentional weight loss after following this advice, ask your doctor or specialist nurse for a referral to the Macmillan Specialist

Stress and anxiety around eating

Cancer treatment can be very stressful and frightening. You may find this puts you off eating and affects your eating habits. Changes in your eating patterns may also cause you and those around you to feel anxious.

Try not to put too much pressure on mealtimes. Make sure you have a calm, relaxed space to eat in. Some people find being distracted with the television, music, book or crossword helps
them to eat more without realising.

It can be helpful to talk to a healthcare professional about how you’re feeling about your cancer and treatment. The Cancer Information and Wellbeing Services has support
facilitators who are happy to listen and discuss with you how cancer is affecting your life.

All cancer patients we treat have access to complementary therapies within the Cancer Care and Haematology Unit at Stoke Mandeville Hospital. For more information about
the services available, speak to one of the support facilitators.

Food safety and chemotherapy

Chemotherapy treatment reduces your ability to fight off infections and can make you more prone to illnesses such as food poisoning. It’s important to follow food safety precautions
when preparing, cooking and reheating foods.

Read our information about food safety advice for people having chemotherapy before you start treatment,

Alternative diets

There’s a lot of attention in the media surrounding diets that claim to cure or control cancer.

There’s currently little robust scientific evidence that any of these diets can improve cancer survival or quality of life.

Some of these diets restrict whole food groups when there’s very little evidence to support doing this. These diets are potentially harmful as they’re often low in energy (calories) and
protein, putting you at risk of nutritional deficiencies and weight loss, which may compromise your cancer treatment.

We don’t recommend alternative diets. If you’re still keen to follow a particular diet, talk to your doctor or nurse specialist and ask to see the Macmillan Dietitians who’ll support you and make sure your diet is nutritionally complete.

Vitamin and mineral supplements

They can be helpful if you’re struggling to maintain a balanced diet or have problems absorbing your food properly during cancer treatment. Your doctor may prescribe supplementation if they think you’re lacking a particular vitamin or mineral.

Alternatively, you can buy a multivitamin and mineral supplement over the counter at most pharmacies and supermarkets. Choose a product that has approximately 100% reference nutrient intake (RNI) for all nutrients.

If you struggle to take whole tablets, try a chewable option such as Centrum Fruity Chewables or Superdrug’s chewable A-Z.

Warning: high dose vitamin and mineral supplements aren’t recommended as they may interact with your cancer treatment. If you have any queries about other supplements or food additives, talk to your healthcare professional.

Vitamin D

Most people can get all the nutrients they need from a balanced diet. The exception is Vitamin D.

It’s difficult to get enough from diet alone. The main source of the vitamin is skin exposure to sunlight. All adults should consider taking 10 mcg each day during the winter months.

Some ‘at risk’ groups, for example, over 65’s and people who cover their skin when outside, should consider taking a daily supplement of 10 mcg /day all year round.


These ‘beneficial’ bacteria found in certain food products or supplements may benefit our health by improving the types of bacteria in our gut (bowels). If you’re healthy and well they have been found to be safe to take. But if your immune system isn’t working properly or you’re on chemotherapy, you shouldn’t take them until 14 days after completion of treatment.

There isn’t enough evidence yet to support taking probiotics during immunotherapy treatment.

What do I eat at the end of my cancer treatment?

If you have no problems with eating, we advise you to follow a healthy, balanced diet. This will help with your recovery and reduce your risk of a cancer recurrence. The World Cancer Research Fund (WCRF) has lots of helpful lifestyle advice and tips for living healthily after cancer treatment.

If you continue to have problems eating after you’ve completed treatment, follow the eating well with a small appetite information until you can return to a healthy, balanced diet.

If you’re concerned about ongoing poor appetite or symptoms, talk to your doctor or nurse specialist who may refer you to the Macmillan Dietitians for further assessment and nutritional support.

Useful resources

Food fact sheets from the Association of UK Dietitians

Eating a healthy balanced diet to reduce your risk of cancer

Alcohol and cancer

Be Healthy Bucks – a health and wellbeing service for residents of Buckinghamshire

Healthy eating and cancer

Move More: Your guide to becoming more active – Macmillan resource with DVD also available from the Cancer Care and Haematology Unit, Stoke Mandeville Hospital,

Free prescriptions

All cancer patients undergoing treatment for cancer, the effects of cancer or the affects of cancer treatment can apply for an exemption certificate for a free prescription from their GP.

How can I help reduce healthcare associated infections?

Infection prevention and control is important to the wellbeing of our patients so we have procedures in place. Keeping your hands clean is an effective way of preventing the spread of infections.

You, and anyone visiting you, must use the hand sanitiser available at the entrance to every ward before coming in and after you leave. You may need to wash your hands at the sink using soap and water. Hand sanitisers are not suitable for dealing with patients who have symptoms of diarrhoea.

More help or advice

Contact our patient advice and liaison service (PALS) on 01296 316042 or

About our patient information leaflets

This patient advice is intended as general information only. We aim to make the information as up to date and accurate as possible, but please note that it’s subject to change.

Always check specific advice on any concerns you may have with your doctor.