Eating well during cancer treatment

Practical tips for eating well during cancer treatment: getting enough protein and energy, coping with poor appetite, nausea and taste changes, food safety, and what to know about supplements.

6 min read · last reviewed September 30, 2026

Food can feel complicated during cancer treatment. You may have heard all kinds of advice from friends, family and the internet. Some days you may not feel like eating at all. That's okay.

Here's the simple truth: during treatment, the main goal is to get enough energy (calories) and protein to keep your strength up. Eating well can help you cope with side effects, heal after surgery, fight infection and feel better day to day. It doesn't need to be perfect.

Why eating well matters now

Cancer and its treatment can change your appetite, your sense of taste and how your body uses food. Many people lose weight and muscle without trying. Keeping your weight steady and your muscles strong can help you get through treatment.

This may be different from healthy eating advice you've heard before. If your appetite is poor, foods that are higher in calories and protein can be a good thing for now. After treatment, you can return to a focus on long-term healthy eating.

Tell your team if you are losing weight without trying, or finding it hard to eat or drink. Ask to see a registered dietitian. They can make a plan that fits your treatment, your tastes and your culture.

Get enough protein

Protein helps your body repair and keeps your muscles strong. Try to include some protein at every meal and snack:

• Eggs, fish, chicken or meat
• Beans, lentils, chickpeas, tofu
• Milk, yogurt, cheese or soy drinks
• Nuts, seeds and nut butters

When you don't feel like eating

• Eat small amounts often, every 2 to 3 hours, instead of three big meals.
• Eat most when you feel best. For many people, that's in the morning.
• Keep easy snacks nearby: yogurt, cheese and crackers, nut butter on toast, a smoothie.
• Drink between meals, not with them, so you don't fill up on liquid.
• Try nourishing drinks like milkshakes, smoothies or nutrition drinks if eating feels hard. Ask your dietitian which ones are right for you.
• Make meals pleasant. Eat with others, or with music or a favourite show.

Coping with common eating problems

Nausea

• Take anti-nausea medicine as prescribed.
• Try plain, dry foods like toast or crackers, and cool foods with little smell.
• Ask someone else to cook, or open a window, if cooking smells bother you.

Taste changes

• If food tastes like metal, try plastic cutlery and cold foods.
• Add flavour with herbs, spices, lemon or marinades (unless your mouth is sore).
• Rinse your mouth before eating.

Sore mouth or throat

• Choose soft, moist foods: soups, eggs, porridge, mashed vegetables, yogurt.
• Avoid spicy, salty, acidic or crunchy foods.

Diarrhea

• Drink plenty of fluids to replace what you lose.
• Eat small meals and try foods that are gentle on your stomach.
• Call your team if it is severe or doesn't settle. With some treatments, such as immunotherapy, diarrhea needs to be reported right away.

Constipation

• Drink plenty of fluids, and move your body if you can.
• Ask your team before adding lots of fibre, and ask about a laxative. Some pain and anti-nausea medicines cause constipation.

Drink enough fluids

Many side effects, such as vomiting and diarrhea, make you lose fluids. Sip water, milk, soups, juice or other drinks through the day. Call your team if you feel dizzy, have a dry mouth, or are peeing much less than usual.

Food safety matters more now

Treatment can weaken your immune system. That makes food poisoning more likely and more serious. Safe food handling helps:

• Wash your hands before preparing and eating food.
• Wash fruits and vegetables well.
• Cook meat, poultry, fish and eggs thoroughly.
• Avoid raw or undercooked meat, fish and eggs, unpasteurized milk, cheese and juice, and raw sprouts.
• Keep cold foods cold, and put leftovers in the fridge quickly.

Some hospitals used to give people a strict "neutropenic diet." Many cancer centres now focus on safe food handling instead. If your team gives you special food rules, such as after a stem cell transplant, follow their advice.

Vitamins, herbs and supplements

It's natural to want to do everything you can. But some supplements can affect how cancer treatment works or cause side effects. For example, high doses of some antioxidant vitamins may interfere with some chemotherapy or radiation. Some herbal products, and even grapefruit, can change how certain medicines work.

• Tell your team about everything you take, including vitamins, herbal teas and "natural" products.
• Ask before starting anything new.
• Food first. It's usually better to get nutrients from food than pills, unless your team tells you that you need a supplement.

Be wary of "cancer diets"

No single food or diet cures cancer. Be careful with diets that cut out whole food groups, promise to "starve" cancer, or ask you to stop treatment. They can make it harder to keep up your strength. If you're curious about a diet, talk it over with your dietitian.

Something you can do this week: Stock your freezer and cupboard with easy, nourishing foods you like, so there's always something ready on hard days. Let friends help with meals.

Questions to ask your care team

• Can I see a dietitian?
• Are there foods or drinks I should avoid during my treatment?
• Is it safe for me to take my vitamins, herbs or supplements?
• What should I do if I lose weight or can't eat?
• Do I need special food safety rules?
• Which eating problems should I call about right away?

This article is general information, not medical advice. Talk with your health care team about your own situation. In an emergency, call 9-1-1 or your local emergency number.

In an emergency, call 9-1-1 or your local emergency number.

General information, not medical advice. It does not replace your own care team. If you think you or someone else is having a medical emergency, call 9-1-1 or your local emergency number. If you are in crisis or thinking about suicide, call or text 9-8-8 (Canada and the US).

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