A low appetite is common during chemotherapy and radiotherapy. Eating small, frequent, nutrient-dense meals rather than three large ones, choosing bland or cool foods for nausea or taste changes, and softening meals for a sore mouth can all help you keep your strength up, even when eating feels like hard work.
If eating has started to feel like a chore rather than something you look forward to, you are far from alone. Somewhere between one in six and one in four people notice a change in appetite around the time of diagnosis, and treatment itself, whether chemotherapy, radiotherapy or both, can make it harder still.
Nausea, changes to taste and smell, a sore mouth, or simple tiredness can all get in the way of eating enough, even when you know you need to. This guide brings together practical, evidence-based ways to keep your strength up without needing to force down large meals, organised by what is actually getting in your way, so you can find what’s relevant to you quickly.
Why Appetite Changes During Cancer Treatment
Appetite loss can come from several directions at once, which is part of why it can feel so hard to manage. Chemotherapy and radiotherapy can directly affect the digestive system and the taste buds. On top of that, nausea, a sore mouth or throat, changes to how food tastes and smells, fatigue and low mood can all reduce how much you want to eat, and often more than one of these is happening at the same time.
None of this means you are doing anything wrong. It’s an expected, well recognised side effect of treatment, and the practical strategies below are built around the specific things that tend to get in the way.
Start With the Basics: Small, Frequent and Nutrient-Dense
- Eat small, frequent meals and snacks rather than trying to manage three large ones. A timer or a regular reminder can help if you tend to forget.
- Eat protein and calories first, while your appetite is at its best, which is often earlier in the day.
- Keep easy, ready-to-eat snacks close by, so eating something doesn’t depend on having the energy to prepare it.
- A short, gentle walk can sometimes help stimulate appetite before a meal.
- Very fried or greasy food can fill you up quickly without giving much nutrition in return, so lighter, nutrient-dense options are usually more useful.
Food Ideas for Taste and Smell Changes
- If food tastes metallic, try plastic cutlery instead of metal, and marinate meat, chicken or fish in something sweet or citrus-based.
- Serving food cold or at room temperature can reduce strong smells that put you off eating.
- Adjust seasoning to how things taste to you right now, a little more if food seems bland, milder if flavours feel too strong.
- If your mouth feels dry, sipping water often and choosing something tart, like a little lemonade, can help.
- Keep up gentle mouth care. A clean mouth genuinely affects how food tastes, so brushing and rinsing regularly is worth the effort.
Food Ideas for a Sore Mouth or Throat (Mucositis)
- Soft, moist foods are easier and more comfortable: think scrambled eggs, mashed potato, milkshakes, smooth soups and custards.
- Cook food until it’s tender and cut it into small pieces.
- Add sauces, gravy or stock to soften and moisten meals further.
- A straw can help you bypass a sore area of the mouth when drinking.
- Cold or room-temperature food tends to be more comfortable than hot food on sore skin.
- Steer clear of citrus, tomato, spicy, crunchy or alcoholic foods and drinks while your mouth is sore.
- Rinsing with a mild, mouth-safe saltwater solution a few times a day can support comfort and hygiene. Ask your care team for their specific recommendation, since practice can vary.
Fortifying Food Without Adding Volume
When you can only manage small amounts, making each mouthful count matters more than eating more of it.
- Stir olive oil, grated cheese or milk powder into soups, porridge or mashed potato.
- Choose full-fat dairy where you can tolerate it, rather than lower-fat versions.
- Add a spoonful of nut butter to porridge or a smoothie for extra calories and protein in a small volume.
- A smoothie or milky drink can carry a surprising amount of nutrition without needing much appetite for solid food.
When to Speak to Your Care Team
Most appetite changes during treatment can be managed with the strategies above, but some signs are worth raising with your care team promptly.
- Losing more than around 1.5kg (3lb) in a week, or more than five percent of your body weight without trying.
- Being unable to eat or drink much of anything for more than two days.
- Nausea or vomiting that is stopping you from keeping fluids down.
- A sore mouth or throat so painful that you can’t eat or drink enough.
- Feeling increasingly weak, dizzy or unusually tired alongside eating problems.
This is also a good time to ask about a referral to a registered dietitian, who can tailor a plan specifically to you, and to ask whether medication to help with appetite or nausea might be appropriate for your situation.
How CanScience Can Help
When whole food is genuinely hard to manage, a nutritional drink can help close the gap rather than replace the foods you enjoy and can already manage.
The CanScience Nutritional Energy Shake is formulated to deliver concentrated nutrition, including protein, in a small volume, which can be useful on days when eating very much feels out of reach. GlutaCan is built around glutamine, an amino acid some people find supportive for digestive comfort during treatment.
Neither is a substitute for professional dietetic advice, and both are best used alongside guidance from your care team or a registered dietitian, but they’re worth knowing about for the harder days.
Key Takeaways
Appetite changes are a very common, expected part of chemotherapy and radiotherapy, not a sign you’re doing something wrong. Small, frequent, nutrient-dense meals usually work better than trying to manage three large ones. Matching your food choices to what’s actually getting in the way, nausea, taste changes or a sore mouth, makes the biggest practical difference. Fortifying small amounts of food with olive oil, cheese or milk powder can add meaningful nutrition without needing to eat more volume. Losing more than about 1.5kg in a week, or being unable to eat or drink for more than two days, are clear reasons to contact your care team.
Frequently Asked Questions
What should I eat when I have no appetite during chemotherapy?
Small, frequent, nutrient-dense meals tend to work better than three large ones. Cool or room-temperature foods, easy options like yoghurt, eggs or soup, and fortifying small portions with olive oil, cheese or milk powder can all help you get enough nutrition without needing to eat large amounts.
Why does cancer treatment affect appetite?
Chemotherapy and radiotherapy can directly affect the digestive system and taste buds, and appetite loss is often made worse by nausea, changes to taste and smell, a sore mouth, fatigue or low mood, all of which are common and expected side effects of treatment.
What foods help with taste changes during cancer treatment?
If food tastes metallic, plastic cutlery and marinating meat in something sweet or citrus-based can help. Serving food cold or at room temperature reduces strong smells, and adjusting seasoning to taste, a little more if food seems bland, milder if flavours feel too strong, can make meals more appealing.
When should I be concerned about weight loss during cancer treatment?
Contact your care team if you lose more than about 1.5kg (3lb) in a week, or more than five percent of your body weight without trying, or if you’re unable to eat or drink much for more than two days. These are good reasons to ask about a referral to a dietitian.
Medical Disclaimer: The information in this article is for educational purposes only and does not constitute medical or dietetic advice. It is not a substitute for professional guidance and is not intended to diagnose, treat, cure or prevent any condition. Always consult your oncologist, care team or a registered dietitian before making significant changes to your diet during cancer treatment.
This article draws on guidance from the National Cancer Institute’s Nutrition in Cancer Care (PDQ) and Eating Hints publications, UT MD Anderson Cancer Center patient guidance on appetite changes, and the American Cancer Society’s guidance on weight changes during treatment. Full citations available on request.
