Eating problems and cancer

Cancer and cancer treatments can sometimes cause eating problems. Below are tips to help you manage your diet if you have eating problems. We also have more information mouth problems that can be caused by cancer treatment.

If you are too tired to cook or eat

Feeling very tired (fatigued) is a common side effect of cancer treatment. It can also be caused by the cancer itself. You may find you are struggling to cook your meals and you are too tired to eat.

Tips to help you cope with tiredness

There are different ways you can make things easier if you are feeling too tired to cook or eat:

  • Use convenience foods such as frozen meals, tinned foods and ready meals. Remember to defrost frozen foods thoroughly and cook all foods properly to avoid any risk of food poisoning. Read and follow cooking instructions carefully.
  • Try to plan ahead. If you have a freezer, prepare food when you are feeling less tired. You can freeze it to use when you are feeling tired. You could stock up on convenience foods, or use a local meal-delivery company.
  • Family, friends or neighbours may want to help in some way. You could ask if they could get some shopping or cook for you.
  • If you really do not want to eat, try having a nourishing drink. You can make a smoothie with bananas, peaches, strawberries or other soft fruit (fresh or frozen). Add these to a blender or liquidiser with fortified milk, plant-based milk, fruit juice, ice cream or yoghurt.
  • Ask your doctor, nurse or dietitian to prescribe or recommend supplement drinks for you.
  • You might feel you need more help at home with 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, 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.

If you have constipation

Constipation means that you are not able to empty your bowels (poo) as regularly as you usually do. It can become difficult or painful for you to empty your bowels. Cancer treatments and medicines such as painkillers and anti-sickness drugs can cause constipation.

Here are some tips that can help with constipation:

  • Eat plenty of fibre each day. Good sources of fibre include: wholewheat breakfast cereals (Weetabix®, Shredded Wheat® or muesli), wholemeal bread, flour and pasta, brown rice and fresh fruit and vegetables.
  • Drink plenty of fluids – both hot and cold drinks will help. Aim to drink at least 2 litres (3½ pints) a day. This is very important if you increase the amount of fibre in your diet. Eating fibre without drinking enough fluids can make constipation worse.
  • You could try a natural remedy for constipation. This includes prune juice, prunes, fig syrup and dried apricots.
  • Gentle exercise, such as walking, will help keep your bowels moving.
  • If you are constipated because of the medicines you are taking, it may be possible to change the dose you take. Talk to your doctor about this.
  • You may need to take laxatives (medicines that help you empty your bowels). Your doctor can give you more advice.
  • If you have cancer of the bowel, or you think your cancer treatment is causing constipation, ask your doctor or specialist nurse for advice.

If you have diarrhoea

Diarrhoea means that you need to empty your bowels (poo) more often than you usually do. It also means your stools are looser than usual.

Some cancer treatments can cause diarrhoea. Sometimes an infection or other medications, such as antibiotics, can also cause diarrhoea.

Diarrhoea can be a temporary, mild side effect. But for some people, it can be severe, and they need to see a doctor to help manage it. Tell your doctor if you have diarrhoea. They can find out the cause and may prescribe anti-diarrhoea medicines.

If your diarrhoea is caused by cancer treatment, you must take the anti-diarrhoea medicines prescribed by your doctor. It is not enough to change your diet. If you have diarrhoea after surgery for bowel cancer, talk to your doctor or specialist nurse before changing your diet.

Here are some tips that can help with diarrhoea:

  • Drink at least 2 litres (3½ pints) of fluids each day. This will replace the fluid lost from diarrhoea.
  • Avoid drinking alcohol and coffee.
  • Eat small, frequent meals made from light foods. This could be white fish, poultry, well-cooked eggs, white bread, pasta or rice.
  • Eat your meals slowly.
  • Eat less fibre, such as cereals, raw fruits and vegetables, until the diarrhoea improves.
  • Avoid greasy, fatty foods such as chips and beef burgers, and spicy foods like chilli peppers.

Sometimes diarrhoea can be severe. Contact the hospital straight away if:

  • you have diarrhoea at night
  • you have diarrhoea more than 4 times in a day
  • you have a moderate or severe increase in stoma activity
  • the anti-diarrhoea drugs do not work within 24 hours.

If you are taking antibiotics

Antibiotics can kill the healthy bacteria normally found in the bowel. But the bacteria found in live yoghurt or yoghurt drinks may replace them. This may help ease diarrhoea caused by antibiotics. You should avoid live yoghurt while you are having chemotherapy or if your immunity is low.

If you have wind

The amount of wind we produce depends on how healthy bacteria and digestive enzymes in our bowel combine with the foods we eat.

Some cancer treatment and some types of medicine can cause wind. It can also be caused by constipation. We have more information about the causes of wind and tips for managing it.

If passing wind becomes painful, tell your doctor.

If you are feeling sick

Some cancer treatments can make you feel sick (nausea). You may also get nausea from some painkillers or antibiotics, or if you have physical problems like constipation or liver damage.

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.

If feeling sick is putting you off your food, these tips may help:

  • Try eating dry food, such as toast or crackers, before you get up in the morning.
  • If the smell of cooking makes you feel sick, eat cold meals or food from the freezer that only needs heating up. Remember to follow the cooking instructions to make sure it is properly cooked.
  • If possible, let someone else do the cooking for you.
  • Avoid fried, fatty foods with a strong smell.
  • Try sitting by an open window while you eat. This will let plenty of fresh air into the room.
  • Sit in an upright position at a table when eating. Stay sitting for a short time after the meal.
  • When you feel sick, start by eating light foods, such as thin soups. Gradually introduce small portions of foods you feel like eating. You can slowly build up to a more varied diet.
  • Food or drinks containing ginger can help reduce nausea. You could try crystallised ginger, ginger tea or ginger biscuits.
  • Some people find peppermint tea reduces nausea. You could add a teaspoon of honey if you prefer a sweeter taste.
  • Sipping a fizzy drink may help. Try mineral water, ginger ale, lemonade or soda water. Sip it slowly through a straw.
  • Try having drinks between meals rather than with your food.
  • Some complementary therapies such as acupuncture may help. But check with your doctor first. Some people find wearing acupressure wristbands helpful. You can buy these from a chemist.
  • Try to make sure you empty your bowels (poo) regularly. Constipation can make you feel sick.

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

If you have lost your appetite

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

If you have problems with your diet or appetite, ask your doctor at the hospital to refer you to a dietitian. If you are at home, your GP or district nurse can refer you to a community dietitian.

They can review your diet and your dietary requirements. They can advise you on which foods are best for you, and whether any food supplements would be helpful.

These tips might help:

  • Instead of having three big meals a day, try eating small, frequent meals or snacks. If you find certain times of the day are better for you to eat, try to eat then.
  • Keep snacks handy to eat whenever you can. Nuts, crisps, dried fruit or cheese and crackers are quite light and tasty. If these are hard for you to chew or swallow, try yoghurt, peanut butter or fromage frais instead.
  • Try to make your food look as attractive as possible. Put small portions on your plate and add slices of lemon or tomato, or parsley. You could use a small plate to serve food on.
  • Drinking a small amount of alcohol just before, or with food, may help to stimulate your appetite. Check with your doctor that you can have alcohol.v
  • 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.
  • Have sweet or savoury nourishing drinks as well as small meals. Sip these slowly through the day. The sugar in these drinks can damage your teeth. It is important to wash your mouth out with water after having any sugary drinks and to brush your teeth regularly.
  • Eat your meals slowly, chew the food well and relax for a little while after each meal.
  • Sometimes the smell of cooking can be enjoyable, but sometimes it can put you off eating. If you have family or friends who would like to help, ask them if they could cook for you. Or try to eat cold foods that do not need cooking, or ready-made foods that can go straight in the oven or the microwave.
  • Everyone’s appetite changes and you may have good and bad days. Make the most of the good days by eating well and treating yourself to your favourite foods.
  • Try to eat your meals in a room where you feel relaxed and where there are no distractions.
  • It may be possible to stimulate your appetite using medicines, such as a low dose of steroids or the hormone medroxyprogesterone. Your doctor may prescribe these for you.

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). It usually happens after meals. It can happen when stomach acid irritates the lining of the stomach or small bowel. Some drugs (such as steroids or anti-inflammatory painkillers) and some cancer treatments (such as chemotherapy) can also irritate the stomach lining. You may get indigestion if you do not eat or drink much, have a small stomach capacity, or do not move around very much.

Tips to help relieve heartburn and indigestion:

  • There are medicines that can help. Your GP or cancer doctor can suggest what might be best for you.
  • 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.
  • Wear loose clothing around your waist.
  • Try not to move around too much for at least 45 to 60 minutes after eating.
  • Try not to lie flat on your back, especially after meals. Use extra pillows in bed or raise the head of the bed by a few inches.
  • If you get indigestion at night, avoid eating a meal or drinking tea or coffee, for 3 to 4 hours before bed.
  • Try to keep to a healthy weight.
  • If you smoke, try to stop or cut down. The chemicals in cigarette smoke may make indigestion worse. The NHS has a lot of information and support to help you give up smoking.

If you are a carer

Preparing food

  • Ask the person you are caring for what they would like to eat.
  • Try to talk openly about their eating problems or weight loss. Talk about the different ways you could both manage it. This can help you both feel more in control of the situation.
  • Try to give them small meals and snacks, whenever they feel like eating. This might be better than eating at set times of the day.
  • Offer their favourite foods at the times when you know their appetite is at its best.
  • The person you are caring for may find that the smell of cooking makes them feel sick. Prepare food in a different room if possible.
  • Keep a range of different foods in the house so that you can offer them something at any time of the day. Tinned foods and pre-prepared frozen meals can be as good for them as a meal that takes a long time to prepare.
  • If they cannot manage solid food, try soft foods. This might include porridge, bananas, soup, shepherd’s pie, yoghurt or milk-based foods like custard or rice pudding.
  • Make batches of their favourite meal and freeze some for a quick meal at another time.
  • Moist food is often easier to eat and will help to prevent a dry mouth, so try adding sauces or gravies.
  • You may need to use a liquidiser or blender for some dishes. You may find it helpful to use meal-delivery companies. Supermarket home-delivery services may make shopping easier for you.
  • Try using supplements to add energy to everyday meals and drinks. For example, you could try adding fortified milk or cream to tea or coffee. You can also add cream, butter or cheese to meals.
  • Take care preparing food if the person you are caring for may be at risk of infections and food poisoning. The doctors or dietitian will be able to advise you about this. We have information about food hygiene and lowered immunity.
  • The person you are caring for may have side effects of treatment. These might be nausea, vomiting, taste changes, a sore mouth or changes to bowel habits. A member of their medical team can either prescribe something to help or refer them to a dietitian.

Serving food

  • Try to serve food in a well-ventilated room to help if the person you are caring for has nausea.
  • Keep servings small. Offer extra helpings rather than putting too much food on the plate to begin with. Too much food can be overwhelming and off-putting.
  • Try not to worry if they cannot always eat what you have cooked. Gently encourage the person you are caring for to eat. But try not to push them too much. It helps to create a relaxed atmosphere at mealtimes.
  • If someone’s sense of taste or smell has changed, it can sometimes help to serve food cold or at room temperature.
  • Use plastic cutlery if the person affected by cancer notices a metallic taste in their mouth.
  • Try to create a comfortable eating environment.
  • Serve meals so they look appetising.

About our information

  • References

    Below is a sample of the sources used in our eating problems information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk

    European Oral Care in Cancer Group – Oral Care Guidance and Support. 1st Edition. Available at: www.eocc.co.uk [Accessed 10.02.2020] 

    National Cancer Institute. Nutrition in Cancer Care. (PDQ) Updated 2019. www.cancer.gov [accessed March 2020] 

    The Royal College of Surgeons of England/The British Society for Disability and Oral Health. The oral management of oncology patients requiring radiotherapy, chemotherapy and/or bone marrow transplantation. Clinical Guidelines. 2018. 

    UK Oral Management in Cancer Care Group (UKOMiC), Oral Care guidance and support in cancer and palliative care (3rd edition), 2019. 


  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Chief Medical Editor, Professor Tim Iveson, Consultant Medical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.