Oncology nutrition focuses on helping people meet their nutritional needs during and after cancer treatment. Proper nutrition supports the body’s ability to heal, maintain strength, and tolerate therapy. It also plays a role in reducing fatigue, preventing unintentional weight loss, and supporting overall recovery1.
Why Nutrition Is So Important in Cancer Care
Cancer and its treatments can alter metabolism, appetite, and digestion. Chemotherapy, radiation, and surgery all increase energy and protein needs while sometimes making it harder to eat enough. Malnutrition occurs in up to 80% of patients with advanced cancer and is linked with poorer treatment tolerance and outcomes2.
Nutrition care during treatment aims to maintain energy balance, muscle mass, and hydration, while easing symptoms such as nausea, mouth sores, taste changes, or diarrhea3.
Core Principles of Oncology Nutrition
- Prioritize calories and protein: Even small, frequent meals can help meet needs. Protein supports immune function and repair1.
- Focus on food tolerance: The “best” diet is the one the patient can eat. Adjust texture, flavor, and temperature to reduce nausea or metallic taste3.
- Manage side effects: Tailored meal plans and hydration strategies help reduce fatigue, constipation, or mouth discomfort4.
- Protect immune health: Safe food handling and avoiding high-risk raw foods reduces infection risk during immunosuppression5.
Sample Small, Frequent Eating Pattern
| Time | Meal Example | Nutrition Focus |
|---|---|---|
| Breakfast | Oatmeal with milk, honey, and nut butter | High-calorie, gentle texture, easy to swallow |
| Mid-morning | Greek yogurt with fruit puree | Protein, probiotics, cool temperature for mouth comfort |
| Lunch | Chicken noodle soup with crackers | Fluids, sodium for hydration, soft texture |
| Afternoon | Smoothie with banana, whey protein, and peanut butter | Protein and calories in liquid form |
| Dinner | Baked salmon, mashed sweet potato, and green beans | Balanced macronutrients; omega-3s for inflammation support |
During Treatment
When appetite or digestion is affected, patients may rely on nutrient-dense smoothies, soups, and fortified foods. The priority is nourishment over “perfect” dietary patterns. Weight maintenance during active treatment is generally more important than pursuing restrictive or alternative diets6.
After Treatment: Recovery and Prevention
Post-treatment nutrition shifts toward rebuilding muscle, restoring stamina, and supporting long-term wellness. Survivors are encouraged to follow the American Institute for Cancer Research (AICR) recommendations: a mostly plant-forward diet, maintaining a healthy body weight, limiting processed foods and red meat, and being physically active7.
Addressing Myths and Misinformation
Many patients encounter confusing nutrition claims online, from “anti-cancer superfoods” to complete dietary restrictions. Evidence does not support extreme elimination diets or high-dose supplements as a cure8. Oncology dietitians help separate evidence from marketing and guide safe, balanced approaches.
Working With an Oncology Dietitian
Oncology dietitians collaborate with oncologists, nurses, and speech or physical therapists to deliver whole-person care. They help patients track weight and symptoms, adjust meals weekly, and support caregivers in preparing food safely3.
Frequently Asked Questions
Should I avoid sugar during cancer?
No, sugar itself doesn’t “feed” cancer directly. The body regulates blood glucose tightly whether from fruit, grains, or other carbohydrates. Restrictive, low-carb diets are rarely appropriate during active treatment because they can worsen malnutrition8.
Are plant-based diets helpful?
Yes. Diets emphasizing fruits, vegetables, beans, whole grains, and healthy fats are associated with better survivorship outcomes, though individual tolerance guides specific choices7.
What about supplements?
Use supplements only when indicated—such as vitamin D deficiency or poor intake—since some high-dose antioxidants may interfere with therapy5.
References
- National Cancer Institute. Nutrition and Cancer overview. cancer.gov
- Arends J, et al. ESPEN Guidelines on nutrition in cancer patients. Clin Nutr. 2017. espen.org
- Oncology Nutrition Dietetic Practice Group, Academy of Nutrition and Dietetics. oncologynutrition.org
- American Cancer Society. Managing side effects of treatment. cancer.org/treatment
- National Comprehensive Cancer Network (NCCN). Food safety during chemotherapy. nccn.org/patients
- National Institute of Health. Managing loss of appetite and taste changes in cancer. cancer.gov/about-cancer/treatment/side-effects/appetite-loss
- American Institute for Cancer Research. Recommendations for cancer prevention and survivorship. aicr.org
- World Cancer Research Fund / AICR. Diet, Nutrition, Physical Activity, and Cancer: A Global Perspective. 2018. wcrf.org