Eating problems

Many people experience eating problems during or after cancer treatment.

Some eating problems, such as a poor appetite or weight loss, may have been symptoms which led to your diagnosis. Some eating problems may be due to the location of the cancer in your body, causing you to feel sick or have poor digestion. Your doctor may try to improve your food intake before treatment starts.

Eating problems can be caused by some cancer treatments. These can be temporary, but sometimes last longer. If you have treatment to your mouth, throat, stomach or intestine, it will take time to return to a regular eating pattern. Treatment such as radiotherapy to the head and neck area may cause a dry mouth and difficulty swallowing. Chemotherapy and targeted therapies can cause sickness, diarrhoea or constipation, taste changes and soreness to your mouth. You could also be at risk of an infection after cancer treatment and your doctor may suggest avoiding foods with harmful bacteria.

Your doctor can refer you to a dietician who will assess your food needs and advise you on which foods are best for you.

Being diagnosed with cancer

Everyone’s nutritional needs will be different when diagnosed with cancer. Some people will feel well and be able to eat normally. For others, weight loss or a poor appetite may have been 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. They will try to improve your food intake before you start treatment.

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

Cancer treatments and eating problems

Some cancer treatments can cause eating problems. Some problems are temporary and improve when you finish treatment. Others may last longer.


In the short-term, surgery can slow down your digestion. If you have surgery to your mouth, throat, stomach or intestine, it can take some time for you to return to a more regular eating pattern.


Radiotherapy to your head, neck or chest area can cause taste changes, swallowing difficulties, a dry mouth and a very sore mouth and throat. Radiotherapy to the tummy (abdomen) or pelvic areas can make you feel sick (nauseous), or be sick (vomit), or it can cause diarrhoea.


Common side effects of some chemotherapy treatments can include loss of appetite, taste changes, constipation, diarrhoea, feeling sick or being sick and a sore mouth.

Targeted (biological) therapy

This can affect your appetite or your ability to eat. Problems might include taste changes, a dry or sore mouth and feeling sick.

‘I found that during and after chemo my taste buds were all messed up, it took a couple of months for things to drift back to as they were.’ - John


Risk of infection

A possible side effect of cancer treatment is an increased risk of infection. This is mainly a side effect of chemotherapy. It happens because the treatment can temporarily lower the number of white blood cells in your body, which help to fight infection. When the number of white blood cells is low, it’s called neutropenia.

Most people having chemotherapy will not need to change their diet. If you are on high-dose chemotherapy, you may be advised to avoid foods that contain harmful bacteria and be careful with food hygiene. This is called a ‘clean diet’ and it can help to reduce your risk of getting an infection. Your specialist nurse will discuss this with you.


If you have any 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’re not in hospital, your GP can refer you to a community dietitian.

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

‘The dietitian I saw twice a week made sure that I was getting enough nutrients to get me back on the road to recovery.’ - John


Other eating problems

Some people with cancer may have particular eating problems that are not covered here. 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 radiotherapy to their mouth or jaw.

If this includes you, you may need to follow a specially designed diet. You can get advice about these diets from your doctor, specialist nurse or dietitian. There are also organisations that can help.