How cancer can affect eating

People with cancer have different dietary needs. Some people feel well and able to eat normally. For others, weight loss or a poor appetite were symptoms that led to their diagnosis. If you had eating problems before you were diagnosed, you may need some support from your doctor or dietitian to improve your diet before you start treatment.

Some eating problems may be related to the cancer itself. Depending on where the cancer is in your body, it can cause you to feel sick (nausea), be sick (vomit), or it can cause pain or poor digestion. The cancer may also change the way your body uses the food you eat, so that you don’t get all the nutrients you need.

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Being referred to a dietitian

Qualified dietitians are experts in assessing the food needs of people who are ill. They can review your diet and they will take into account any specialist dietary requirements you have. They can advise you on which foods are best for you, and whether any food supplements would be helpful.

If you have problems with your diet, you can ask your doctor at the hospital to refer you to a dietitian. In some hospitals, you can refer yourself. Contact the hospital’s dietetic department for more information. If you are not in hospital, your GP or district nurse can refer you to a community dietitian, who will visit you at home.

How treatment can affect eating

Some cancer treatments can cause eating problems. Some problems are temporary and improve when you finish treatment. Others may last longer. Your doctor, specialist nurse or dietitian will support you and advise you on what might help.


Some types of surgery can slow down your digestion. If you have surgery to your mouth, throat, stomach or bowel, you may need to adjust to changes in your eating patterns.


Radiotherapy to your head, neck or chest area can cause:

  • taste changes
  • swallowing difficulties
  • a dry mouth
  • a sore mouth and throat

Radiotherapy to the tummy (abdomen) or pelvic area (the area between the hips) can make you feel sick or be sick. It can also cause diarrhoea.


Common side effects of some chemotherapy treatments include:

  • loss of appetite
  • taste changes
  • constipation
  • diarrhoea
  • feeling sick or being sick
  • a sore mouth.

Targeted therapy

Targeted therapies can affect your appetite or your ability to eat. Problems might include:

  • taste changes
  • a dry or sore mouth
  • feeling sick.

Foods to avoid if your immunity is low

Cancer or treatments for cancer may increase your risk of infection. Some treatments can temporarily lower the number of white blood cells in your body that help fight infection. Having a lower number of white blood cells than normal is called neutropenia.

If your immunity is very low, you might need to avoid certain foods. Your doctor, nurse or dietitian will be able to tell you whether you need to avoid any of these foods:

  • cheeses made from unpasteurised milk (and other foods or drinks made from unpasteurised milk)
  • mould-ripened and blue-veined cheeses
  • liver pâté
  • yoghurt or other products that contain probiotics
  • fresh salads
  • raw meats and seafood
  • runny eggs.

We have more information about infection.

Following a special diet

Some people with cancer may have specific eating problems, for example:

  • people with diabetes
  • people who have a colostomy or ileostomy
  • people who have had all or part of their stomach or bowel removed
  • people who have had radiotherapy to their mouth or jaw.

If you have any of the above, you may need to follow a special diet. Your doctor, specialist nurse or dietitian can give you advice.

If you have a sore or dry mouth

Some cancer treatments can damage the cells that line your mouth or throat. Soreness and ulceration of the lining of the mouth or throat is called mucositis. It can be very painful. Mucositis can be caused by chemotherapy, targeted therapies, or radiotherapy to the head and neck.

We have tips if you have a sore or dry mouth.

If you are too tired

Feeling very tired (fatigued) is a common side effect of cancer treatment. It is often worse towards the end of a course of radiotherapy or chemotherapy and for some weeks after treatment has finished. You may find you are struggling to cook your meals and you are too tired to eat.

Here are some tips to help you cope with tiredness:

  • Family, friends or neighbours may want to help in some way. You could ask if they could get some shopping or cook for you.
  • Try using convenience foods such as frozen meals, tinned foods and ready meals. Defrost frozen foods thoroughly and cook all foods properly to avoid any risk of food poisoning.
  • Try to plan ahead. Prepare food when you are feeling more energetic and freeze it. You could stock up on convenience foods or use a local meal-delivery company.
  • If you really don’t want to eat, try a nourishing drink. You can make a smoothie by blending bananas, peaches, strawberries or other soft fruit (fresh or frozen) with fortified milk, fruit juice, ice-cream or yoghurt in a liquidiser or blender.
  • Your doctor, nurse or dietitian can prescribe or recommend supplement drinks for you.
  • If you feel you need more help at home with your cooking or eating, tell your GP or contact the dietitian at your hospital. They may be able to arrange for you to have meals delivered (meals on wheels) or for someone to help you prepare your food.
  • It may be easier to eat smaller meals more often throughout the day rather than a few bigger meals.

We have more tips on coping with fatigue that you may find helpful.

If you have constipation or diarrhoea

Some chemotherapy drugs, anti-sickness drugs and painkillers can cause constipation.

If you have bowel cancer, or you think your cancer treatment is causing constipation, ask your doctor or specialist nurse for advice.

Chemotherapy, radiotherapy, targeted therapies and surgery can all cause diarrhoea. The treatments can affect the healthy cells that line the digestive tract, which causes diarrhoea. Sometimes an infection or other medications, such as antibiotics, can also cause diarrhoea.

Sometimes diarrhoea can be severe. It is important to contact the hospital if this happens. If you have more than 4 to 6 episodes of diarrhoea a day, contact the hospital on the telephone numbers you have been given and speak to a doctor or nurse.

We have more information about managing bowel and bladder problems and what may cause it.

If you have wind

Constipation and some types of medicines can also cause wind. Pelvic radiotherapy (to the lower tummy area) can cause wind. This is because the pelvic floor muscles can become weaker. Some types of bowel surgery may cause problems with wind. If you find wind difficult to cope with, talk to your doctor or specialist nurse. If passing wind becomes painful, tell your doctor.

We have tips for coping with wind.

If you are feeling sick

Some cancer treatments can make you feel sick (nausea). These include some chemotherapy, hormonal therapy and targeted therapy drugs, and radiotherapy to the brain, stomach, bowel or close to the liver. Some painkillers and antibiotics, and physical problems like constipation or liver damage, can also cause nausea.

There are very effective treatments to help prevent and control sickness. Your cancer specialist or GP can prescribe anti-sickness (anti-emetic) drugs for you. Tell them if your anti-sickness drugs are not helping, as there are different types you can take.

We have more detailed information about coping with nausea and vomiting.

If you have problems chewing and swallowing

Chemotherapy and radiotherapy treatments for head or neck cancer can affect the cells in the lining of the throat. This can make it painful to chew or swallow. An infection in your mouth or throat, such as thrush, can also make chewing and swallowing uncomfortable.

Let your doctor or dietitian know if you are having any difficulties. If you find that drinks make you cough, you should tell your doctor or specialist nurse as soon as possible. A speech and language therapist (SLT) can advise you about swallowing problems.

Tips for coping with difficulties chewing or swallowing

You may find that taking painkillers before meals can help you chew and swallow more easily. Your doctor or nurse can suggest what might be best for you to take.

  • Keep eating your favourite foods when possible. You could try cooking them in sauces and gravies.
  • Finely chop meat and vegetables, then casserole or stew them.
  • Cut the crusts off bread for softer sandwiches.
  • If you have a blender, you could liquidise cooked foods.
  • Some frozen-meal home-delivery companies have a soft-food range on their menu.
  • There are several food supplements that you may find helpful, for example Complan®drinks. You can buy these from your chemist or supermarket. Your doctor may give you a prescription for some of them. Your GP or dietitian can explain which food supplements might be best for you.

If you have changes in appetite

During cancer treatment, you may lose your appetite. This may be because you feel sick or tired, or because food and drink taste different.

Tips to help with your appetite

  • Try eating smaller meals more often, and garnish them so they look more appealing.
  • Keep snacks handy, like nuts, crisps, dried fruit or cheese and crackers. If these are hard for you to chew or swallow, try yoghurt, peanut butter or fromage frais instead.
  • Try stimulating your appetite with a small sherry or brandy half an hour before you eat. A glass of wine with meals may also help digestion. Check with your doctor that you can have alcohol.
  • If you have recently had surgery or radiotherapy for bowel cancer, you may need advice about the best foods for you. Talk to your dietitian, specialist nurse or doctor.
  • Sweet or savoury nourishing drinks can be used alongside small meals. You can sip these slowly through the day.
  • If the smell of cooking puts you off eating, ask family or friends if they could cook for you. Or eat cold foods that do not need cooking or ready-made oven meals.
  • Your appetite may go up and down. Make the most of the good days by eating well and treating yourself to your favourite foods.
  • Your doctor may prescribe medicines to help your appetite. These may include a low dose of steroids or the hormone medroxyprogesterone.

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Big appetite due to medicines

Some medicines, such as steroids, may increase your appetite. If this happens, try to eat healthy foods such as fruit and vegetables instead of sweets and crisps.

We have more information about making healthy food choices.

If you have heartburn or indigestion

Heartburn is a burning sensation behind the breastbone. It can be very painful. It is caused when acid from the stomach irritates the lining of the gullet (oesophagus).

Indigestion is discomfort in the upper part of the tummy (abdomen), happening especially after meals. It can happen when stomach acid irritates the lining of the stomach or small bowel. Some drugs can irritate the stomach lining. These may include:

  • steroids
  • anti-inflammatory painkillers
  • some cancer treatments (such as chemotherapy).

You may get indigestion if you have a small stomach capacity, do not eat or drink much, or if you do not move around very much.

Tips to help relieve heartburn and indigestion

  • Talk to your doctor. They can try to find out the cause and prescribe medicines to help.
  • Make a note of any foods that cause discomfort so you can avoid them.
  • It may help to avoid large meals, chocolate, alcohol, fatty and spicy foods, fizzy drinks, chewing gum, hard-boiled sweets, mint, aniseed and dill.
  • Limit activity for at least 45 to 60 minutes after eating.
  • Try not to lie flat on your back, especially after meals.
  • If you get indigestion at night, avoid eating, or drinking tea or coffee, for 3 to 4 hours before bed. If you need a drink, have water. Sleep in a semi-upright position, propped up on pillows.
  • If you smoke, try to stop. Smoking may make indigestion worse. We have more information about giving up smoking.

Your feelings about eating problems

You may feel self-conscious about eating at home or out with family or friends. You may worry that changes in your eating will affect your relationships with your partner, family or friends. Or you may be anxious about what people think of your eating problems.

Many people find that it helps to talk to someone close to them. If you find it difficult to talk about your feelings with your family, you could speak to your doctor, specialist nurse or GP. There are ways they can support you.

We have an online tool that you can use to search for support groups in your area. We also have more information on coping with your emotions.

Getting help with meals

You may not always feel well enough to cook food for yourself or others. This may be frustrating. If you are the person who usually prepares the meals for your family, it may feel strange to let someone else take charge. Try not to feel guilty about letting someone else do the things you usually do. When you feel better, you can get back into your normal routine.

If you live on your own and need help with cooking or shopping, contact your GP, district nurse or social worker. They may be able to arrange for a home helper, meals on wheels or a local organisation to help.