Eating well when you have cancer

Eating good food is important when you are well, and it is also very important when you are receiving treatment for cancer.

When you have cancer, it is vital that you eat well so you will:

  • feel better and have more energy
  • get the most benefit from your treatment with fewer side effects
  • improve your body’s ability to heal, and to fight infection
  • maintain a healthy weight.

You may be wondering if you are eating the right foods, or if you need to change your diet. This topic looks at healthy eating, food safety, and food tips to maintain weight.

Are there any foods that should be avoided?


There are no foods you must eat or avoid when you have cancer, but there are probably some changes you can make in your diet to keep you healthy. Once a cancer has developed, it cannot be cured through diet alone. There is no evidence to support claims that special diets or single nutrients, such as a particular vitamin, can cure cancer.

Some diets or nutrients do no harm, but there are some that are harmful and can interfere with the success of your treatment. If you are thinking about making a dramatic change to your diet, look at your choices closely and discuss them with your doctor or dietitian.

Aim for variety

If you are already eating a healthy diet, you probably do not need to change. Choosing a wide variety of healthy foods is something very positive that you can do to help you feel stronger and maintain a healthy weight.

You can check how you are doing by following these guidelines, which will provide all the nutrients you need. If your traditional diet includes food different from those listed, talk to your treatment team. 

Energy and fuel for the body

Every day you need calories to provide fuel for your body to do daily activities and maintain body weight. Calories are provided by the different food groups below.


Protein maintains and renews your body tissues and helps your body defend itself against infection. Sources of protein include milk and milk products, and lean meats, poultry, fish, eggs, nuts and pulses.

Milk and milk products

Have at least two servings of milk or milk products a day. One serving is a glass of milk, or two slices of cheese, or a pottle of yoghurt, or dairy food. You can also choose cottage cheese, soft cheeses, ice cream, or milk puddings. Choose trim milk and low fat products unless you need high energy foods to maintain your weight.

Milk and milk products are a valuable source of calcium for bone health. If you choose not to have cows’ milk products, calcium fortified soy or rice products should be included as substitutes.

Lean meats, poultry, fish, eggs, nuts, and pulses

Have at least one serving a day. Choose lean meat, chicken, fish (a serving size is equivalent to the size of your palm), cooked eggs, nuts, and pulses (dried beans, peas, and lentils), eg. baked beans, tofu, lentil burgers, bean salad, and lentil soup. Meat, chicken, and fish also provide iron and zinc.

Use low fat cooking methods, such as stewing, baking, microwaving, grilling, or poaching. Remove visible fat from meat and chicken.


Carbohydrates provide fibre, vitamins, and minerals, and are an important calorie source. Carbohydrates include breads and cereals and fruits and vegetables.

Breads and cereals

  • Have six servings of breads and cereals a day.
  • These foods should form the basis of most meals and snacks.
  • You can choose from breakfast cereal, rice, couscous, polenta, pasta, semolina, sago, pikelets, muffins, scones, crackers, roti, chapatti, naan, plain biscuits, and other products made from grains.
  • Ideally, they should be wholemeal or wholegrain, if tolerated, for additional fibre.

Vegetables and fruits

  • Have at least five servings of vegetables and fruit each day.
  • Choose from potato, kumara, pumpkin, taro, or yams.
  • Also include some dark green, orange, and yellow vegetables, eg. broccoli, peas, silverbeet, spinach, corn, carrot, cauliflower, cabbage, Brussels sprouts, puha, or watercress.

Fruit can be fresh, stewed, or canned, eg. apples, bananas, peaches, apricots, or pears. Vegetables and fruit provide a wide range of vitamins and minerals, as well as carbohydrates and fibre.


Eat less of these foods, or use sparingly unless you are having difficulty maintaining your weight. You can choose from butter, margarine, oils, cream, peanut butter, and coconut cream. Fats provide energy and vitamins A, D, E, and K.


You also need plenty of fluid every day. Have at least eight glasses of water (1500ml) or other drinks a day (more if your doctor recommends it). Limit alcohol, coffee, tea, and caffeinated drinks, as they act as a diuretic (which means you will pass more urine and, therefore, require more fluids).

Vitamins and minerals – food is the best source

Vitamins and minerals help your body use the food you eat. The best source of vitamins and minerals is food. If you follow the guidelines outlined here, it is unlikely that you will need vitamin and mineral pills. Some people believe that if a little bit of a nutrient is good for you, then a lot must be better. There is no scientific evidence to support this idea.

High doses of some nutrients can have harmful effects and some vitamins, herbal supplements, and minerals should not be taken during treatment. Discuss with your oncologist or dietitian any vitamin and mineral supplements you are taking or think you should be taking.

Food safety

Food safety is of special concern to cancer patients, especially during treatment, which may suppress immune function. To make food as safe as possible it is recommended patients follow the guidelines below:

  • Wash hands thoroughly before eating.
  • Keep all aspects of food preparation clean, including washing hands before preparing food, and washing fruit and vegetables.
  • Handle raw meat, fish, poultry, and eggs with care, and clean thoroughly any surfaces that have been in contact with these foods. Keep raw meats separate from cooked food.
  • Cook meat, poultry, and fish thoroughly, and use pasteurised milk and juices.
  • Cover and refrigerate food promptly to minimize bacterial growth.
  • When ‘eating out’, avoid foods that may have bacterial contamination, such as salad bars, sushi and raw or undercooked meats, fish, poultry, and eggs.
  • If there is any concern about the purity of your water, eg, if you have well or tank water, have it checked for bacterial content.

Weight maintenance

Ideally you should stay at the same weight you were before you had cancer, but you may find it difficult to maintain your weight during treatment. If you were a little overweight before you had cancer, you might think that it will not hurt to lose a few kilos. However, losing weight during treatment can be harmful. The effects of your cancer and of reduced activity may be that this weight is lost from muscles rather than from fat stores. If you maintain your weight it can help you recover better from the effects of cancer and its treatment.

If you are losing weight, include frequent meals and snacks in your diet. Also include some of the high energy foods listed in this topic (below). You should talk to your nurse, doctor, or radiation therapist if you are concerned about your weight: they can arrange an appointment with a dietitian. 

Foods high in energy (calories) and protein

Use these foods when you are not eating well or you are losing weight.

  • Butter, margarine, oil, mayonnaise, dressings, avocado, coconut cream: Use with bread, rice, pasta, vegetables, when frying, in salads, dips, and in curries, or casseroles.
  • Milk, skim milk powder, cream, ice cream, evaporated or condensed milk, cheese, sour cream, cream cheese: Use in puddings, fruit, cereals, sauces, soups, in casseroles, on vegetables, in salads, on biscuits, and in drinks.
  • Double strength milk: sprinkle three tablespoons of skim milk powder into 600ml (one pint) of milk and whisk until the powder is dissolved.
  • Blending – one or more of the following may be blended into a glass of milk: Yoghurt, ice cream, skim milk powder, mashed/pureed fruit, powder/liquid flavourings, essence, cordial.
  • Nuts and dried fruit: snack on these between meals.
  • Tofu: add to soups, vegetables, and dried bean dishes.
  • Peanut butter, honey, jam, marmalade, golden syrup: spread on bread, crackers, and baked products. Add to porridge or puddings.
  • Sugar: add to drinks, desserts, and cereals. Use ordinary cordials and fizzy drinks rather than ‘diet’ or low calorie versions. Eat cakes, biscuits, baked products, chocolate, and sweets between or after meals.
  • Pickles, chutneys, pate, hummus, and other dips: add to crackers, bread, and in cooking.

Fluids that provide energy

Choose fluids that provide energy, eg, milk, cordials, non-diet drinks, soups and juices.

Nutritional supplement drinks

Nutritional supplement drinks are not a meal replacement. They should be used in addition to meals and snacks when you need to gain weight, or if you are not eating normally. These provide all the major nutrients found in food plus vitamins and minerals.

Some brand name supplements are listed below. They are available from supermarkets and pharmacies. Those marked with an * can be obtained on prescription, but you will need to have a ‘special authority number’, which your specialist can arrange. If you think you would benefit from these products, talk to your doctor or nurse.

Powders that are mixed with milk or water
These can be purchased from a supermarket. They do not meet all your nutritional needs.
Powders that are mixed with milk or water
These provide all your nutritional needs if consumed in the right quantity.
Ready made drinks
These provide all your nutritional needs if consumed in the right quantity.
Complan Fortisip powder** (note: previously called Nutridrink) Ensure Plus*
Vitaplan Ensure powder*

Resource Plus**
Sustagen classic Sustagen hospital formula* Fortisip** and 
Fortisip Multi-fibre**

 *Low lactose  **Lactose-free

Fortified fruit juice

These juices do not meet all your nutritional needs, but do supply additional calories, protein, and carbohydrate. These juices are not available on prescription.

  • Enlive
  • Resource fuit beverage
  • Fortijuce.


Emotions & cancer Cancer Society of NZ, 2010
How we can help Cancer Society of NZ
NZ cancer services - find a hospital/service near you Healthpoint
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Learn more

Physical activity and nutrition Cancer society (NZ), 2015
Nutrition and childhood cancer Kids health (NZ), 2013
Cancer and food Better health channel (AU), 2014
Nutrition for People With Cancer American Cancer Society (US)

Credits: Original material provided by the Cancer Society of New Zealand, 2007, and edited by everybody, August 2008. Reviewed by everybody, July 2013. Reviewed By: Health Navigator Team Last reviewed: 05 Mar 2015