Nutrition
Cancer
Through treatment the priority is maintaining weight, muscle and strength — this is not the time for restrictive eating.
What you are aiming for
- Prevent unintentional weight and muscle loss
- Meet raised protein needs during and after treatment
- Manage symptoms that block eating: nausea, mouth sores, taste change, early fullness
- Eat safely when immunity is low
Build meals around
- Protein at every meal and snack: eggs, dairy, fish, chicken, beans, tofu, nuts
- Energy-dense additions when weight is falling: oil, butter, cream, milk powder, nut butters, honey
- Soft, moist foods when the mouth is sore: stews, soups, porridge, custard, smoothies
- Cold or room-temperature foods when smells trigger nausea
- Small frequent meals rather than three large ones
- Fluids between meals rather than with them, to avoid filling up
Limit or avoid
- Unpasteurised dairy, raw eggs, undercooked meat and unwashed produce when immunity is low
- Grapefruit and some herbal supplements, which interact with chemotherapy
- Alcohol during treatment, particularly with mouth or throat involvement
- Very spicy or acidic foods when the mouth is sore
- Unproven restrictive 'anti-cancer' diets that cause weight loss
Meal timing
- Eat by the clock rather than by appetite — every two to three hours.
- Eat the largest meal when your appetite is best, often the morning.
- Take anti-sickness medication before eating, not after nausea starts.
Portions
- Small portions, more often. A full plate can be enough to put you off entirely.
- Aim for a protein source at every eating occasion, however small.
- Fortify rather than increase volume — add calories to what you can manage.
A sample day
- BreakfastPorridge made with full-fat milk, honey and nut butter
- Mid-morningFortified milkshake or yoghurt
- LunchChicken and vegetable soup with added cream, soft bread
- AfternoonCheese and crackers, or custard
- DinnerFish pie with mashed potato and soft vegetables
- EveningMilky drink or ice cream
Common myths
“Sugar feeds cancer, so it must be eliminated.”
All cells use glucose. Cutting out carbohydrate does not starve tumours, but it does cause weight loss that worsens outcomes.
“You should fast or juice to cleanse during treatment.”
Weight and muscle loss during treatment is associated with worse tolerance and outcomes. Discuss any fasting protocol with your oncology team first.
Treatment-related challenges
- Chemotherapy: nausea, taste change, mouth ulcers, diarrhoea or constipation.
- Radiotherapy to head, neck or abdomen: pain on swallowing, dryness, bowel changes.
- Surgery: raised protein needs and altered digestion.
- Steroids: raised appetite and blood glucose, then a crash.
See a registered dietitian if
- · Any unintentional weight loss of 5% or more
- · Difficulty swallowing or persistent mouth pain
- · Head, neck, oesophageal, gastric or pancreatic cancer — refer early
- · Considering any restrictive diet or supplement
Afya Companion offers education and self-help support. It does not diagnose, treat or replace care from your doctor, nurse, psychologist or dietitian. If something in your health changes, speak to your care team.