📋 General principles of cancer nutrition

During treatment, your body needs to get enough energy: unless it is measured individually, the ESPEN guideline (2021) estimates the requirement as for a healthy person, generally 25–30 kcal per kilogram of body weight per day. Protein is essential for rebuilding tissue, recovering after surgery and maintaining the immune system. For cancer patients, ESPEN recommends a protein intake above 1 g per kilogram of body weight per day and, if possible, up to 1.5 g/kg per day. Good-quality sources include eggs, dairy products, poultry, fish and pulses.

Unlike nutritional advice for the general population, in cancer care strict food restrictions can do more harm than good. The Canadian Cancer Society emphasises that there is no evidence that sugar "feeds" cancer any more than it feeds any other cell. It is more important to eat — even if it is not perfect — than to go without because of unnecessary restrictions.

The basic principle is flexibility. If you have nausea, choose cold, bland foods. If you have mucositis, avoid acidic and hard foods. If fatigue dominates, keep it simple: smoothies, yogurt, hard-boiled eggs. Cancer nutrition adapts day by day to the reality of your body.

• ✓Prioritise calories and protein over food restrictions
• ✓There is no evidence that sugar preferentially feeds cancer
• ✓Flexibility and adaptation are more valuable than perfection
• ✓More than 1 g of protein per kg of body weight per day (up to 1.5 g if possible) is the ESPEN recommendation