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Diet advice during chemotherapy


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You do not need a special diet when you are having chemotherapy. It is more important to have a nutritious and well-balanced diet. This will help you cope with any side effects of chemotherapy, prevent weight loss or nutritional deficiencies, reduce the risk of infections and help you recover from treatment.

The information on this page will help you eat well during chemotherapy. There is information about weight changes during chemotherapy, and food safety during chemotherapy.

If you have any questions or concerns, please ask your oncology dietitian or nurse. 

Supplements or special diets

There are dietary supplements, herbal preparations and anti-cancer diets that claim to cure cancer or help slow its growth. However, there is no reliable scientific evidence to support this.

If you decide to take dietary supplements of any kind, please talk to your oncology dietitian or doctor first. They can make sure you have the correct information and make an informed decision.

Eating well with chemotherapy

Eating well means eating a varied and balanced diet. This will give your body all the nutrients it needs to function well. These nutrients include proteins, carbohydrates, fat, vitamins, and minerals.

The following information will give you ideas on how to have a balanced diet that gives you enough calories, and the nutrients your body needs.

Try to:

  • eat at least 3 meals every day, and include a variety of foods that you enjoy
  • have starchy carbohydrate foods (such as bread, potatoes, rice, pasta, yam, plantain, chapattis and cereals) with every meal, these foods will give you energy
  • have meat, poultry, fish, eggs, cheese, yoghurt, beans, Quorn, tofu or lentils at least 2 times a day, these foods will give you protein
  • have fruits and vegetables with your meals every day, these have the vitamins and minerals you need
  • drink at least 6 to 8 cups of fluids every day, as well as water try tea, coffee (in moderation), fruit juice, fruit squash, soups, milky drinks and smoothies

Making meals easy

Nutritious meals do not have to be hot meals. They can be quick to make. Sandwiches, flans and quiches, tinned fish and meats can all go towards making a nutritious meal.

If you are finding cooking difficult or tiring, try using convenience foods which can be as nutritious as home cooked meals. Many supermarkets have a wide range of frozen, chilled, packet and tinned foods and meals.

Weight changes with chemotherapy

Weight changes can occur during chemotherapy. You might lose weight, or gain weight. A slight change in your weight during chemotherapy is not a concern.

Weight loss

Significant weight loss can affect how you cope with chemotherapy.

Losing a lot of weight over a short amount of time can lead to loss of muscle. This can mean you have less strength, feel weak, feel very tired (fatigue) and are less able to do your day to day activities.

Weight loss during chemotherapy might be due to side effects, such as:

  • loss of appetite
  • taste and smell changes
  • a dry or sore mouth
  • feeling sick and being sick (nausea and vomiting)
  • finding it hard to poo (constipation) or having diarrhoea
  • feeling very tired (fatigue)

Your oncology doctor can give you medicines to help with some of these side effects. For example, mouthwashes, anti-sickness medicines, pain relief, laxatives for constipation, and medicines for diarrhoea.

Loss of appetite

If you have lost your appetite, or the amount of food you eat is affected by any side effects, there are some simple steps that can help. 

Try to:

  • eat little and often
  • enrich your foods with butter, cheese, cream, honey or syrup to get more energy (calories) into the foods you eat
  • choose high-energy snacks such as cheese and biscuits, cakes and full fat yoghurts
  • if you are finding it hard to eat solid foods, have more nutritious fluids such as milkshakes

An oncology dietitian can give you more practical advice on how to manage some of the chemotherapy side effects, and how to enrich your meals to help you maintain or gain weight.

Weight gain

Some people have unwanted weight gain during chemotherapy. This might be because they are doing less physical activity, and eating more due to boredom or stress, or it might be due to steroid-related increased appetite.

In the short term, a slight increase in weight is not a concern. In the longer term, it can affect your health. Your oncology dietitian can give you advice on how to manage your weight.

Food safety and chemotherapy

Chemotherapy can affect the body’s natural defence against infections. This means your immune system might be weakened. 

Food safety while having chemotherapy is very important to lower the risk of food poisoning.

The best way to make sure food is safe is to cook food properly. This reduces the numbers of germs to a safe level. You should also store food at correct temperatures, and avoid contaminating cooked food with other foods, kitchen utensils or people.

The following information has some practical ways to make sure your food is safe and there is less risk of food poisoning. 


  • Check expiry and ‘use by' dates on food labels.
  • Avoid mouldy, bruised or damaged fruits and vegetables.
  • Avoid foods with damaged or broken packaging.
  • Make sure you get chilled and frozen foods home from the shop as soon as possible.


  • Keep your fridge between 0C and 5C.
  • Keep your freezer below -18C.
  • Chill foods properly. Especially foods with a ‘use by’ date, cooked dishes, and ready-to-eat foods such as prepared salads, cut fruits and desserts.
  • Cool cooked food within 2 hours, and cover food before storing it in the fridge or freezer.
  • Store raw and cooked foods in separate areas or shelves. Cooked and ready-to-eat foods should be at the top of the fridge, and raw meats at the bottom of the fridge in a covered container.
  • Throw mouldy food and any food past its ‘use by’ date away.
  • Do not re-freeze raw food once it has been defrosted, unless you have cooked it first.
  • Leftover food should not be kept in the fridge for more than 2 to 3 days.

Preparing food

  • Wash hands thoroughly before preparing food. 
  • Wash hands thoroughly after touching raw foods such as meat, poultry, fish, eggs and unwashed fruit and vegetables.
  • Make sure all the surfaces you are using are clean before you start preparing food.
  • Cooked food should not come into contact with raw meat, unwashed vegetables or salads, or with utensils, cloths or surfaces that have been in contact with raw food.
  • Use separate chopping boards for raw food and ready-to-eat food.
  • Wash salads, fruit and vegetables thoroughly before eating.


  • Thaw frozen foods in the fridge and cook as soon as it is thawed.
  • Make sure food is cooked properly and is piping hot throughout.
  • When cooking with a microwave, turn and stir food halfway through the cooking time so it cooks evenly.
  • Serve hot food as soon as possible after cooking.
  • Do not reheat cooked food more than once. If you do, make sure it is piping hot throughout.

Eating out

  • Always ask for your food to be freshly prepared.
  • Make sure hot foods are served piping hot and cooked all the way through.
  • Avoid buying food from salad bars, buffets, street vendors and ice cream vans.

Foods needing extra care 

Some foods have a higher risk of carrying germs. It is important to be careful when you prepare, cook and store these food to limit the risk of food poisoning.


  • Store eggs safely in a cool dry place, such as a fridge.
  • Follow ‘best before’ dates.
  • Eating lightly-cooked eggs is safe as long as they are produced under the British Lion Code of Practice (and have the British Lion symbol stamped on them). If you choose lightly-cooked eggs when eating out, check that these eggs are British Lion eggs. 
  • Avoid foods containing raw eggs, such as home-made Caesar salad dressing and hollandaise sauce.

Poultry, red meat and products

  • Cook thoroughly and do not serve pink or rare.


  • Serve as soon as rice is cooked.
  • If storing cooked rice, cool quickly within 1 hour of cooking and store in the fridge.
  • Do not store cooked rice in the fridge for more than 1 day.
  • When reheating cooked rice, make sure it is steaming hot all the way through.

Milk, cheese and yoghurts

  • Pasteurised milk and cheese products are safe to eat, but avoid unpasteurised products.
  • Avoid mould-ripened and blue veined cheeses such as Brie, Camembert, Gorgonzola and Roquefort.
  • Cheeses that are safe to eat include:
    • hard cheeses such as Cheddar, Cheshire, Derby, double Gloucester, Edam, Emmental, Gouda, Gruyère, Parmesan and red Leicester
    • soft cheeses such as cottage cheese, mozzarella, feta, cream cheese, paneer, ricotta, halloumi, goats’ cheese, Quark and processed cheeses including cheese segments
  • Avoid supplements, food and drinks containing probiotics (such as bio-yoghurts, Actimel, Yakult and supermarket own brands). These contain live bacteria and although they are considered safe, they need to be used with caution during chemotherapy.

Fish, oysters, and other seafood

  • Do not eat raw seafood, such as oysters or shellfish.
  • Sushi made from frozen raw fish and cooked shellfish are safer to eat, as freezing and cooking will reduce the risk of food poisoning.
  • Make sure smoked salmon is stored in the fridge and eaten before its ‘use by’ date.

Oncology dietitians

The oncology dietitians can give you information, advice and support during your treatment.

They can help if you:

  • are losing weight (more than 2kg since your last appointment)
  • are underweight
  • are struggling with eating and drinking due to:
    • poor appetite
    • taste changes
    • swallowing difficulties
    • feeling full
    • dry mouth
    • sore mouth
    • changes in bowel habits
  • have questions about alternative diets

You can request to be referred to an oncology dietitian for support with any of the above by your doctor or nurse. 



Ref number: 4008/VER3

Date published: February 2018 | Review date: February 2021

© 2018 Guy’s and St Thomas’ NHS Foundation Trust

A list of sources is available on request


Where next?

 Contact us

If you have any questions or concerns, contact the oncology dietitians at the Nutrition and Dietetics Department 

Phone 020 7188 4128 Monday to Friday, 9am to 5pm.

If we cannot take your call, leave a message and we will call you back.

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