Beating bowel cancer together

Diet after treatment

After your cancer treatment you may find you can’t eat the same foods as you did before. This page has information about eating a balanced diet, eating when you have a stoma and how diet can help with problems like weight change, diarrhoea and constipation.

If you have recently been diagnosed with cancer or if you’re having treatment for cancer, speak to your healthcare team or dietitian for diet advice.

A balanced diet

It’s important to follow a healthy, balanced diet to help you feel physically and emotionally well. Our information on healthy eating for reducing the risk of bowel cancer may be helpful.

Try to eat plenty of vegetables and fruits each day, with some lower fat dairy products and lean protein like skinless chicken, fish or pulses. Limit your intake of saturated fats and sugars. Carbohydrates, such as bread, pasta and rice, are important for energy but choose wholegrains unless your healthcare team has advised you to follow a low fibre diet.

The NHS Choices website has an Eatwell Guide, which shows how much of each food type to include in your diet. Remember, this is general information so you may need to change it to meet your needs during and after cancer treatment.

The foods you can eat may vary during and after your cancer treatment and you may find you can’t eat the same foods as you did before bowel cancer. Remember that your balanced diet will be individual to you. It will depend on your age, body weight, gender and how active you are.


A diet rich in fibre (wholegrains, pulses, vegetables and fruit) is important for bowel health, as it helps move food more quickly through the bowel. Fibre also keeps you feeling full for longer, and so can help you control your weight and appetite. Increase fibre gradually and drink plenty of fluids like water, low fat milk or herbal teas, to avoid wind, bloating and stomach cramps.

Your healthcare team will explain how much fibre you need. Talk to them if you have any problems with your diet. 

How much fibre?
Healthy adults should eat at least 30g of fibre a day. Your healthcare team will explain how much fibre you need to include in your diet, depending on which treatment you’ve had. If you have any problems and find that you can’t cope with high-fibre foods, speak to your dietitian or healthcare team.

Low fibre diets
After treatment, you may be advised to follow a low fibre diet. This means you may find you can no longer eat high fibre foods such as bran, nuts or seeds. If this is the case, you could try foods containing gentler soluble fibre like oats and pulses. Cooking fruit and vegetables and removing the skins can also make fibre easier to digest. Over time, you should be able to gradually increase the amount of fibre you eat.

You may need to follow a low fibre diet, for example, before and after treatment but make sure you ask your healthcare team how long you should follow this diet for. You may be able to gradually start eating more fibre after a few weeks. Your healthcare team should also explain how much fibre you need, but if you have any problems or questions about your diet, talk to them.

Adding fibre to your diet
It is important to increase fibre gradually to avoid wind, bloating and stomach cramps. For example, you could add an extra portion of vegetables to your diet every few days. Fibre attracts water so it’s important to drink plenty of fluids like water, low fat milk or herbal teas. Try to avoid sugary, fizzy and caffeinated drinks wherever possible.

Should I take supplements?

You should be able to get all the vitamins and minerals you need from a healthy, balanced diet. But you may need supplements if there are some foods you can’t eat, if you follow a vegan or other restricted diet, or if you have a poor appetite.

Ask your healthcare team about seeing a dietitian, who can make sure you’re getting all the vitamins and minerals you need. Don’t take high doses of supplements as they can be harmful. It is especially important not to take any vitamins or food supplements during your cancer treatment unless they’ve been recommended by your doctor, dietitian or other qualified healthcare professional.

Eating with a colostomy

Many people with a colostomy are able to eat a healthy, balanced diet. But if you had constipation or diarrhoea before having a colostomy, you may find that you continue to have these symptoms.

Whether you have constipation or diarrhoea it is important to stay hydrated and drink six to eight glasses of liquid a day. Water is best but you can also have tea, coffee or sugar-free squash. Try to limit fruit juice to no more than one glass a day.

If you have constipation, make sure you’re eating enough fibre and have at least five portions of vegetables and fruit each day. Eating meals at regular times, spicy foods and high fibre foods can help to relieve constipation.

For the first few days after surgery, make sure vegetables are well cooked. You may cope better with cooked, rather than raw, fruit.

Get medical advice straight away if you haven’t had a poo for more than a few days and you have pain, feel sick or have been sick (vomited).

If you have diarrhoea, see your GP or stoma nurse. They may give you medicine to slow the movement of food through your bowel and thicken the output. Foods that may thicken output include very ripe bananas, boiled rice, porridge, smooth peanut butter, white bread or pasta. As well as losing water with diarrhoea, you will be losing salts and other important nutrients. To replace these, try eating fresh or tinned soups and broths. You could also have Marmite on toast or plain crackers.

If you feel too sick to eat, or if you become very dehydrated, your GP may suggest you use oral rehydration salts. These contain a balance of salts and sugars to help your body re-absorb them quickly. You can buy them from pharmacies and supermarkets.


Eating with an ileostomy

When you first have an ileostomy, you may find that some types of food are harder to digest. Chew your food well and introduce fibre gradually.

Avoid fruit straight after surgery, except for bananas which thicken the output from your stoma. Gradually introduce cooked fruit, like stewed apple.

After six to eight weeks, you should be able to start eating more types of food. You can eat vegetables and fruit as part of a healthy, balanced diet, but chew them well to reduce the risk of blockages. If you have problems eating these foods, you could try taking off the skin and removing the seeds or eating tinned vegetables and fruit in natural juice or water.

A blockage can cause pain in your stomach area (abdomen) and bloating. You may feel sick and your stoma may stop working. These symptoms should settle if you stop eating for 24 hours but carry on drinking liquids. You can also cut the opening of your stoma appliance slightly larger as they may swell and massage the area around your stoma. A warm bath can help to ease the pain.

Get medical help from your stoma care nurse or hospital emergency department if you start being sick (vomiting) or if the pain doesn’t get better.


Eating with a low appetite

The side effects of cancer and its treatment can affect your appetite and your ability to eat. You may not have enough help with food shopping or preparing meals or, if you live alone, you may not feel like going to the trouble of cooking for one person.

Speak to your GP, specialist nurse or dietitian if you're having problems with eating enough. They can give you emotional support and practical help to eat a balanced diet. If you're a family member or carer and you’re worried about someone who has lost their appetite, you can speak to a healthcare professional on their behalf.

Small amounts of exercise such as a gentle walk before meals can increase your appetite and eating at similar times each day will help to regulate your appetite. Adding herbs, spices and seasonings can make food taste better and increase your appetite to eat. It can help to make large meals that can be divided into smaller portions, for example soups, pies and bakes.


Losing weight safely

There are several possible reasons for putting on weight after treatment. You may have felt too tired to exercise during treatment, you may have taken comfort in eating or you may have felt low and found it hard to eat healthily.

Speak to your healthcare team before trying to lose weight. They can give you information on which types of food you should eat, depending on the treatment you’ve had and any side effects you’re having.

Following a healthy, balanced diet and doing regular physical activity can help you lose weight. Aim for at least 30 minutes, five days a week, and avoid sitting for long periods of time.


Gaining weight safely 

Speak to your GP or healthcare team if you’ve lost a lot of weight or if you’re losing weight quickly. It’s important to find out what’s causing your weight loss and you may need treatment.

If you’re finding it hard to put on weight, ask your GP or healthcare team to refer you to a dietitian.

There may be several possible reasons for your weight loss. The cancer itself can affect your appetite and treatment can cause bowel problems, like constipation and diarrhoea, which can affect your appetite.

Other side effects, like fatigue, a change in smell and taste, feeling and being sick and emotional stress can also lead to problems with eating. You may be eating normally but still losing weight. Getting medical advice and treatment for these symptoms may help you to eat more and put on weight.

Eating four to six small meals rather than three large ones a day can help you to eat more calories and digest your food more easily. Try to include energy-rich foods, such as nut butters, avocado, greek yoghurt or a little coconut cream with your meals or snacks. Regular gentle physical activity can help to build up your muscle strength.

Ask your GP or healthcare team to be referred to a physiotherapist, who can help you find activities that are safe to do during and after cancer treatment.

Can diet help to prevent bowel cancer coming back?

We don’t yet know how to stop bowel cancer coming back after treatment. There’s some suggestion that these things may help reduce your risk of cancer coming back but we need more evidence before we can say this for sure:

  • Staying a healthy weight
  • Being physically active for at least 30 minutes each day, and sitting less
  • Avoiding high calorie food and sugary drinks
  • Eating more wholegrains, vegetables, fruit and beans
  • Limiting red meat and avoiding processed meat
  • Avoiding alcohol if possible. If you do drink alcohol, drink no more than 14 units a week and spread it out over the week.

Making healthy lifestyle choices is good for your overall health and can prevent or reduce other health problems, like diabetes and heart disease.


More information

Find out more about eating and drinking with diarrhoea and constipation after treatment

 Download our Eating well booklet


Updated April 2019

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