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Eating and drinking

You should try to eat a healthy and balanced diet during radiotherapy.

What to eat and drink

Your radiographer (sometimes called a radiotherapist), doctor or nurse can advise you on how to eat well. They can also arrange for you to see a dietitian if you are having problems with eating. You usually see a dietician weekly if you're having head and neck radiotherapy.

It is important not to diet during radiotherapy so that you don't lose weight. Your radiotherapy plan is specific to your size and shape. If your weight changes a lot your radiotherapy plan may need to be planned again. 

If you're struggling to eat normal foods you can try high energy and high protein foods. These include:

  • meat
  • fish
  • eggs
  • cheese
  • full fat milk
  • pulses (peas and beans)

If you don't have much appetite you can add extra energy and protein to your diet, without actually having to eat more food. You can have high energy drinks as milkshakes or soups. And you can add high protein powders to your normal food. Your doctor or nurse can prescribe these for you.

It is important to drink plenty of fluids, at least 2 litres a day if possible.

External beam radiotherapy doesn't make you radioactive. You can cook and prepare food as normal for yourself and other people. If you have a type of radiotherapy that makes you radioactive your doctor or radiographer tells you in advance and they explain if you have to avoid doing anything. 

Tips for eating well

You could try some of the following tips if you are having trouble eating:

  • Have small snacks through the day rather than large meals – eat little and often.
  • Have a soft or liquid diet if swallowing is difficult.
  • Avoid alcohol – it can aggravate a sore mouth or a sensitive digestion.
  • Avoid spicy foods if your mouth or throat are sore.
  • Ask staff about potential problems and how to try to prevent them before you start your treatment if possible.
  • Tell the radiotherapy staff about any problems you have with eating or drinking – they can arrange for you to talk to a dietician.
  • Ask the staff if you need any food supplements.
  • Avoid foods that make you gassy or constipated if you're having pelvic radiotherapy.

What to do if you have problems

Focus on eating high fat foods if you are having difficulty eating enough. There are more calories in fat than in protein or carbohydrate. 

Remember that you might lose a little weight during radiotherapy. But if you are having any problems with eating tell the staff involved in your treatment.

Alcohol during radiotherapy

Usually it is fine to have small or moderate amounts of alcohol during your treatment. But alcohol can inflame a sore mouth or throat if you are having radiotherapy to your head or neck area. 

Radiotherapy can make you feel tired and alcohol can make this worse. It is important not to drive or operate machinery if you feel tired or dizzy.

Ask your doctor or radiographer if you are not sure whether you can drink alcohol.

Last reviewed: 
24 Jan 2019
  • External Beam Therapy (2nd edition)
    Peter Hoskin
    OUP Oxford, 2012

  • Devita, Hellman and Rosenberg's Cancer Principles and Practice of Oncology (10th edition)
    VT Devita, TS Lawrence and SA Rosenberg
    Wolters Kluwer Health, 2015

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