1. Will breast cancer treatment affect what I eat?
2. How soon can I eat after breast surgery?
3. Will chemotherapy affect my diet?
4. Will radiotherapy affect my diet?
5. Will hormone therapy affect my diet?
6. Shopping and cooking during treatment
7. Diets for other medical conditions

1. Will breast cancer treatment affect what I eat?

Many people wonder what foods they should eat and avoid while having breast cancer treatment, and how their diet may change.

Breast cancer treatments such as chemotherapy and hormone therapy can have a range of side effects, some of which may affect what you want to eat and drink. Your usual routine may be disrupted, which can affect your eating pattern. You may also find that going through a stressful and anxious time affects your appetite, causing you to eat more or less than normal.

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2. How soon can I eat after breast surgery?

Most people feel ready to eat again the day after surgery and find their appetite returns to normal as the days go on. Eating well will help your body recover and heal.

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3. Will chemotherapy affect my diet?

It’s hard to tell how your body will react to chemotherapy. You may be able to eat normally throughout your treatment or the side effects may cause your eating habits to change.

Find out more about chemotherapy and its side effects.

Healthy eating during chemotherapy if your appetite is small

If your appetite is small, eating little and often can be better than facing a large meal. You could try:

  • eating five to six small meals or snacks each day instead of three big meals
  • drinking milkshakes, smoothies, juice or soup if you don’t feel like eating solid food
  • doing something active, if you feel able to, as exercise can help increase your appetite for instance, you might have more of an appetite if you take a short walk before lunch

Be careful not to reduce your appetite by drinking too much liquid before or during meals.

Foods to eat during chemotherapy if your appetite is increased

Some of the drugs given alongside chemotherapy, such as steroids, can stimulate your appetite. If you’re worried about gaining weight:

  • choose low-fat foods and drinks
  • eat plenty of fresh fruit and vegetables
  • watch out for the sugar content of food including some ‘diet’ foods
  • avoid sugary drinks

Nausea and vomiting

Nausea (feeling sick) and vomiting (being sick) can be a problem for some people during and after their chemotherapy treatments. Anti-sickness drugs can help with nausea and vomiting. Your chemotherapy team can help you find one that works for you.

Drink plenty of fluids, such as water or herbal teas. Taking frequent sips is better than trying to drink large amounts in one go.

Eating little and often is a good way to combat nausea. Herbal teas such as mint or ginger can also help settle the stomach.

Sore mouth

Chemotherapy can make your mouth sore or dry, making it uncomfortable to eat.

You might find it helpful to:

  • clean your teeth or dentures with a soft brush after eating, and floss gently.
  • choose soft or liquid foods such as soups, stews, smoothies and desserts.
  • soothe your mouth and gums with ice cubes and sugar-free ice lollies.
  • drink sugar-free fizzy drinks to freshen your mouth.
  • use a straw to drink.
  • avoid crunchy, salty, very spicy, acidic or hot foods 

Taste changes

Your taste may change during chemotherapy, making foods taste bland or different. You may prefer to eat strongly flavoured foods, and using herbs and spices in cooking may help. Try a variety of foods to find the ones you like the best. As well as going off your usual foods, you may find that you like foods that you previously did not like.

Some types of chemotherapy can give you a metal taste in your mouth. Using plastic cutlery, instead of metal, can help reduce the metal taste. Using glass pots and pans to cook with can also help.


Eating and drinking less than usual, being less active and taking certain medications can all lead to constipation. Consuming high-fibre foods can help if you’re constipated. These include:

  • wholemeal bread
  • high-fibre breakfast cereal
  • beans and lentils
  • vegetables (fresh or frozen)
  • fresh and dried fruit

You should also drink plenty of fluids and do some regular, gentle exercise such as walking. If you’re still having problems with constipation, ask your specialist or GP (local doctor) for advice.


Occasionally, some chemotherapy drugs can cause diarrhoea. Your GP or specialist can prescribe medication for diarrhoea if necessary.

Contact your chemotherapy team if you have four or more episodes of diarrhoea within a 24-hour period.

Risk of infection

Chemotherapy can cause a drop in white blood cells, which can increase the risk of getting an infection. You’ll have regular blood tests throughout your treatment to check your blood count. If you’re at an increased risk of infection, you may be advised to follow a specific diet, avoiding foods that contain higher levels of harmful bacteria. Your chemotherapy team will explain more about this if necessary.

We should all follow food hygiene guidelines when storing, preparing and cooking food. This is particularly important if you’re at increased risk of infection.  You can find the NHS food hygiene guidelines on their website.

Short-term fasting around the time of chemotherapy

Some studies have suggested that short-term fasting around the time of chemotherapy treatment may help reduce side effects. However, more research is needed before any recommendations can be made.

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4. Will radiotherapy affect my diet?

Having radiotherapy should not cause any dietary problems but it’s still good to eat a balanced diet and drink plenty of fluids.

If you have to travel for your treatment, take a drink and snack with you and plan meals that are easy to prepare for when you get home. Read more about shopping and cooking during treatment.

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5. Will hormone therapy affect my diet?

Weight gain 

Some people who are having hormone therapy as part of their breast cancer treatment find their weight increases. More research is needed to understand why this is.

High cholesterol

Hormone therapy drugs such as anastrozole and letrozole can increase the level of non-high density lipoprotein (also known as ‘bad cholesterol’) in the blood.

If you have too much ‘bad cholesterol’ it can build up in the artery walls, leading to artery disease or other health conditions.

Following a healthy diet and maintaining a body weight in the normal range can help to reduce your levels of ‘bad cholesterol’. Your doctor will be able to tell you more about how cholesterol levels are measured and what dietary changes you may need to make.

Find out more about cholesterol on the British Heart Foundation website.

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6. Shopping and cooking during treatment

Simple tasks like shopping and cooking can seem exhausting during your treatment and as you recover. Try to accept any offers of help, even if you’re used to coping on your own. You can also take advantage of online shopping or ask local shops if they have a telephone ordering and delivery service.

It’s important to have fresh food in your diet, but if you can't shop regularly, frozen and tinned fruit and vegetables are full of nutrients and can be eaten every day. Choose tinned fruit in juice rather than syrup and tinned vegetables that have less salt.

Find out more about coping with fatigue during and after treatment.

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7. Diets for other medical conditions

If you’re already following a specific diet because you have a medical condition – such as diabetes, Crohn’s disease or irritable bowel syndrome (IBS) – having breast cancer doesn’t mean your diet has to change. However, if you’re concerned about how your breast cancer treatment may affect your diet or any existing condition, talk to your breast care nurse or cancer specialist team. They can talk to a dietitian or other medical staff to ensure any existing condition remains under control during your treatment.

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Last reviewed: 2017
Next planned review begins 2019

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