AI generated image of doctor and female cancer patient discussing medical nutrition plan.

The Importance of Nutrition in Cancer Care: Guidance to Support Patients With Cancer

Alys Johns

Specialist Head and Neck Cancer Dietitian

Understanding the Role of Nutrition

A healthy and nutritious diet is very important during cancer. Good nutritional status can reduce the risk of some side effects and support recovery. However, cancer and its treatment can also affect your metabolism, increasing your need for certain nutrients.

Learn about the link between cancer and nutrition and how you can support your body with the foods on your plate.

AI generated image of male cancer patient opening fridge door.

How Cancer Changes the Body’s Nutritional Needs

Cancer and its treatments can increase your metabolism, causing higher protein and calorie requirements than usual (1). At the same time, treatments like chemotherapy or radiation may suppress your appetite or cause side effects that make it hard to eat enough calories and protein.

When your body can’t keep up with cancer’s nutritional demand you may develop malnutrition. You may also lose weight and significant amounts of muscle mass — a condition common in people with cancer, called sarcopenia, which affects strength, muscle function, and energy levels.

Good nutrition before, during and after cancer treatment helps address the specific and increased nutritional needs you may have. It can help you maintain muscle and body weight, so you can feel stronger.

How Cancer and Treatment Affect Eating and Nutrition

It’s estimated that 30-80% of people lose weight because of their cancer or treatment (1,2). Major reasons include:

Cancer and treatments cause inflammation in the body, which in turn speeds up your metabolism, causing weight loss and muscle wasting.
Some cancers and cancer treatments can cause pain or mouth sores, which may make it difficult for you to eat or drink enough to get the nutrients you need.
Some cancer treatments can cause side effects like nausea, vomiting, or diarrhoea, which can reduce appetite and reduce the amount of food available for your body to use as fuel.
It’s also normal to struggle with anxiety, depression, and exhaustion while undergoing cancer treatment. These further affect your appetite, your ability to prepare meals and how well you eat.

DID YOU KNOW?

A healthy diet provides the fuel your body needs during cancer treatment and for recovery.

What Nutrients Are Most Important in Cancer?

Certain nutrients, such as protein and omega-3 fats, are especially important to nutritionally address the risk of muscle loss.

You may not always be able to eat a healthy diet during cancer treatment and that’s OK. However, when you’re feeling well, it’s important to boost your nutrition as much as possible and focus on these nutrients.

Protein

Protein is a critical nutrient that your body needs in increased amounts during cancer, in order to maintain muscle, including such maintenance after surgery, to support your immune system, and other things. Ideally, you should have a source of protein with each meal. As a rough guide, you should aim for 1.5 grams per kilogram body weight per day (1). If you are unsure how much you should aim for, contact your healthcare provider.

Aim to finish all of the protein on your plate. Good sources of protein include:

Eggs
Milk, Greek yoghurt, and cheese
Fish or seafood
Chicken or turkey
Lean beef
Plant-based options: chickpeas, lentils and tofu

Fats

Foods high in fat are a good energy source for our body and are often an easy way to add extra calories. Foods high in healthy fat sources include:

Oily fish such as salmon, sardines, and anchovies
Nuts, seeds and nut butter
Olive oil, ghee, and butter
Full-fat dairy products such as yoghurts, cheese and cream

Consuming more omega-3-rich foods, such as oily fish, walnuts, seeds, and plant oils, can help meet the increased nutritional needs for fat during cancer.

Starchy Carbohydrates

Carbohydrates are your body’s main energy source. Carbohydrate-rich foods like potatoes, winter squash, cereal, chapati, bread, pasta, and rice are great sources of energy and should be included with each meal.

Vitamins and Minerals

Vitamins and minerals are essential for your body to function. Some vitamins such as C and D, and the minerals zinc and selenium, are essential for your immune system and your ability to fight infections, which is particularly important when you are having cancer treatment.

The best way to meet your vitamin and mineral needs is by choosing a fresh, colourful and varied diet focusing on whole foods.

If you are experiencing changes in appetite or side effects that limit your eating and drinking, tell your healthcare provider. They can assess whether you can still meet your nutritional needs with a normal diet, including food supplements, or whether medical nutrition should be recommended.

Fibre

Fibre plays an important role in regulating bowel movements, which is helpful if you’re experiencing changes to your bowels due to cancer treatments. Adults are recommended to eat 30 g of fibre daily (3). These foods are excellent sources of fibre:

Fresh fruits and vegetables
Beans, lentils, and chickpeas
Chia seeds and flaxseed meal

If increasing fibre doesn’t improve your bowel habits, contact your healthcare provider.

When Normal Diet Alone Isn’t Enough in Cancer Care

For some people, it can be difficult to get all the nutrients their body needs from the foods they are eating.

If you’re struggling with poor appetite or unintentional weight loss, it’s important to talk to your healthcare team. They can assess you and, if necessary, recommend additional nutrition support in the form of:

Oral nutrition supplements - These special medical supplement drinks provide lots of calories, protein and other key nutrients in small servings. They can help meet your body’s nutritional requirements and are convenient to sip on throughout the day.
Tube feeding (enteral nutrition) - This delivers nutrition through a tube placed in your stomach or small intestine. This may be recommended by your doctor or medical team if it is challenging to meet your body's nutrition needs orally.
IV (intravenous, or parenteral) nutrition - This delivers nutrition directly into your bloodstream. Your healthcare provider will recommend this only if your digestive system isn’t working effectively.

Adequate nutrition is an important part of your cancer treatment and recovery. It gives your body the fuel it needs to function efficiently, maintain strength, and keep you nourished.

References:

[1] Ravasco P. Nutrition in Cancer Patients. J Clin Med. 2019;8(8):1211.
[2] Nutricia. Cancer and Weight Loss. Available at: https://www.nutricia.com/specialize/oncology/weight-loss (accessed August 25, 2026)
[3] NHS. How to Get More Fibre Into Your Diet. Available at: https://www.nhs.uk/live-well/eat-well/digestive-health/how-to-get-more-fibre-into-your-diet/ (accessed August 25, 2026)
(additional source: https://pmc.ncbi.nlm.nih.gov/articles/PMC7769854/ )

Disclaimer

This information is provided for educational purposes only. It is general in nature and is not intended to replace professional medical advice, diagnosis, or treatment. Always consult your healthcare team regarding any questions or concerns about your health or care.