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Diet during breast cancer treatment

Learn about how different breast cancer treatments might affect your diet and how you can manage these changes.

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.

Find out more about diet and breast cancer.

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.

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 side effects.

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. 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 tips on storing food, and preparing and cooking food safely on the NHS website.

Healthy eating during chemotherapy if your appetite is small

If your appetite is small, or taste changes are affecting your diet, eating little and often can be better than facing a large meal. It may help to:

  • Eat five to six small meals or snacks each day instead of three bigger meals
  • Drink milkshakes, smoothies, juice or soup if you don’t feel like eating solid food
  • Do 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

Find out more about managing weight loss.

Foods to eat during chemotherapy if your appetite is increased

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

  • Eat plenty of fresh fruit and vegetables
  • Choose low-fat foods and drinks
  • Watch out for the sugar content of food including some ‘diet’ foods
  • Avoid sugary drinks

Find out more about managing weight gain.

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 can help if you’re feeling sick. Herbal teas such as mint or ginger can also help settle the stomach.

Some people find that eating cold food makes them feel less sick because hot food can produce more of a smell.

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
  • Use an alcohol-free mouthwash (your chemotherapy team may recommend one)
  • 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
  • Avoid citrus drinks like lemon, lime, orange and grapefruit juice

If you have dentures, clean them regularly and try not to wear them all the time.

Smoking and drinking alcohol can make a sore mouth worse.

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 reusable plastic or wooden 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.

Eating high-fibre foods can help if you’re constipated. These include:

  • Wholemeal bread
  • Wholewheat pasta
  • Brown rice
  • High-fibre breakfast cereal, such as bran flakes or shredded wheat
  • Beans and lentils
  • Vegetables (fresh or frozen)
  • Fresh, frozen, canned and dried fruit

Drink plenty of fluids (six to eight glasses a day) and do some regular, gentle exercise such as walking.

If you’re still having problems with constipation, ask your treatment team or GP 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.

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.

If you’re thinking about fasting, always talk to your treatment team or GP first.

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.

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 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 healthy body weight can help to reduce your levels of bad cholesterol. Your doctor can 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.

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.

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 treatment 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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Quality assurance

Last reviewed in January 2020. The next planned review begins in April 2023.

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