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Weight loss and malnutrition

Nutrition is the food and drink you need for your health and wellbeing. Food is your body’s fuel and what you eat and drink gives you energy, protein, vitamins and minerals. These are all needed to make sure your body works well.

Good nutrition is important for people who have cancer. If you do not give your body enough fuel (food and drink) this can cause weight loss. If this happens, you are at risk of malnutrition.

How common is malnutrition for people with cancer?

Malnutrition is common in people with cancer, but it is not always a side effect of cancer. One in every four people with cancer are malnourished. 

It is important to understand that malnutrition can happen to anyone. It does not matter what size or shape you are or if you are overweight or underweight. 

Get support

Risk factors

Many factors can increase the risk of malnutrition, including:

  • cancer and treatment for cancer, which can cause your body to use more energy and protein, and/or make it more difficult to eat
  • feeling unwell
  • stress and worry
  • feeling tired.

Peter MacCallum Cancer Centre's malnutrition screening tool can help identify and reduce your risk of malnutrition. It is also available in languages other than English.

Side effects

Sometimes it is hard to tell if you have malnutrition. Some signs include:

  • losing weight without trying
  • needing to tighten your belt
  • your clothes feeling loose
  • eating less than usual.

Malnutrition information in other languages

Learn more about preventing weight loss for people with cancer in your own language by downloading our free PDF resource.

It's available in 10 languages including Arabic, Croatian, Greek, Italian, Macedonian, Simplified Chinese (Mandarin), Spanish, Traditional Chinese (Cantonese), Turkish and Vietnamese.

Download the resource

Prevention and management

Malnutrition should be prevented at all stages of the cancer journey as it can:

  • increase your chance of infection
  • reduce how well your treatment works
  • reduce how well your immune system works
  • increase the time you spend in hospital
  • worsen side effects from treatment
  • make you lose muscle and feel weak
  • stop you from doing everyday tasks
  • increase the time it takes for wounds to heal.

Protein foods are important to prevent and manage malnutrition. Protein foods help your body to build and repair muscle during treatment and recovery. Eat the protein part of your meal first, and try to snack on protein foods between meals. High protein foods include:

  • meat (beef, lamb, pork, goat, kangaroo, veal)
  • poultry (chicken, turkey, duck)
  • fish and seafood (fish, prawns, crab)
  • eggs
  • dairy (full cream milk, cheese, yoghurt, custard, ice cream, milkshakes, smoothies, and soy-based products) – nut, oat and rice milks are generally lower in protein
  • nuts and seeds (whole nuts and seeds, peanut butter)
  • beans (lentils, kidney beans, baked beans, chickpeas)
  • tofu.

If your weight has reduced, you might need more energy to fuel your body. Add high energy foods to your meals and snacks, such as

  • full cream dairy products including butter and cream
  • fats and oils including vegetable oil, margarine, mayonnaise, avocado, peanut butter.  

Other tips to prevent or manage malnutrition

  • Eat small meals and snacks every few hours.
  • Eat more when you feel most hungry.
  • Take note of how much you eat and drink, and of any change to your weight.
  • Stay active to help build and repair your muscles.
  • If you are taking any nutrition, vitamin or herbal supplements, tell your doctor or nurse. This is important because they can affect how your medications and treatments work. 


Get support

A dietitian is a specialist in food and nutrition. Every person has different nutrition needs, and a dietitian can help you meet your own nutrition needs to prevent and manage malnutrition. If you think you might have malnutrition, you should see a dietitian.

  • If you are currently having treatment for cancer, you can ask your doctor or nurse to refer you to a dietitian in your hospital or health service.
  • If you are not currently having treatment, you can find a dietitian at your local health service or in your community. You could also ask your doctor to refer you.
  • You can call our trusted and compassionate cancer nurses on 13 11 20 for information and connections to local support services.

More about nutrition and cancer

Preventing Weight Loss

Download our Preventing Weight Loss fact sheet to learn more and find support

Download now  



The review of this information was a collaboration between the Victorian Cancer Malnutrition Collaborative (VCMC) and Cancer Council Victoria, and funded by Western and Central Melbourne Integrated Cancer Service. This information has been developed with help from a range of health professionals and people affected by cancer.

Page last updated:

The information on this webpage has been adapted from Preventing weight loss - Why is it important for people with cancer? (2021 edition), which is based on a Cancer Council Victoria resource entitled Understanding Malnutrition and Cancer. This webpage was last updated in July 2022.

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