Lung Cancer

Lung Radiotherapy and Diet: What to Eat and What to Avoid

Embarking on lung radiotherapy can be a challenging journey, but with the right dietary approach, you can support your body through the process. In this article, written by award-winning dietitian, Jo Cunningham, of Green Light Nutrition: Cancer & Gut Dietitian Clinic we’ll discuss what to eat before treatment, offer advice for managing radiation-induced oesophagitis, and provide general tips for maintaining your health during follow-up.

What to Eat Before Treatment:

Before starting radiotherapy, focus on nourishing your body with a balanced diet rich in nutrients. This Mediterranean style diet, which is well evidenced to be the best type of diet for those living both with and without cancer. Here are some key tips to consider:

High-Protein Foods: 

Incorporate lean proteins such as chicken, fish, tofu, and beans into your meals to support muscle strength and repair. Red meat can be included in moderation. 

Whole Grains: 

Opt for whole grains like brown rice, quinoa, and whole wheat bread to provide sustained energy throughout the day. These also nourish the gut microbiota to support reducing inflammation in the body.

Fruits and Vegetables: 

Load up on colourful fruits and vegetables, which are packed with vitamins, minerals, and antioxidants to support your immune system. Variety is what we’re aiming for to provide a balance of nutrients and fibre. It’s better to have a mouthful of 5 different veggies at meal compared to 5 mouthfuls of one vegetable!


Stay well-hydrated by drinking plenty of water and herbal teas. Proper hydration is essential for supporting your body’s natural detoxification processes. As a rough guide, aim for 2 litres of fluid per day. 

Managing Radiation-Induced Oesophagitis:

Radiation-induced oesophagitis is inflammation in the oesophagus (food pipe) which can occur after radiation therapy, and often for lung, breast and other thoracic cancers. It can cause discomfort and difficulty swallowing, and reduced oral intake as a result. 

Here are some dietary strategies to help alleviate symptoms:

Soft and Moist Foods: 

Choose soft, moist foods that are easier to swallow and less likely to irritate your oesophagus. Examples include mashed potatoes, yoghurt, smoothies, and soups. Don’t forget make these nutrient dense by adding extra plant foods. For example, mash in broccoli and carrot to mashed potatoes, add ground nuts or nut butters to yoghurts, and blend in beans, lentils, and other vegetables into soups and casseroles. Soft and moist doesn’t have to be totally bland!

Avoid Trigger Foods: 

Some foods may irritate the lining of the food pipe, so notice whether alcohol, spicy foods, acidic fruits and juices (e.g. citrus fruits), and carbonated beverages trigger for you, and temporarily look to avoid these. Melons, apples, pears and bananas are less acidic and less likely to trigger symptoms. Note that not all of these trigger for everyone, so only exclude what you need to. 

Avoid Temperature Extremes:

Very hot or very cold foods may aggravate symptoms, so aim to have foods at room temperature whilst your symptoms are settling. 

Small, Frequent Meals: 

Divide your meals into smaller, more frequent portions to reduce the strain on your oesophagus. This eating pattern can help you maintain adequate nutrition without discomfort. If you’re struggling to maintain your weight then speaking with a dietitian will provide you with personalised advice. 

Nutritional Supplements: 

Oral nutritional supplement drinks can be prescribed to help you meet your nutritional requirements if you’re struggling. A dietitian can provide you with samples to help you work out which products are right for you, and then liaise with your GP to arrange a prescription. The dietitian will explain how these products can be used within your day – they aren’t usually to replace your existing meals, but to supplement the diet to support you during this acute phase. In some cases hospital admission for nutrition support may be needed and your dietitian will discuss this with you and your oncologist if appropriate. 

Other Supplements:

Caution when it comes to taking supplements (herbal, nutritional & other) whilst on cancer treatment as herb-drug interactions are common. One supplement which has been associated with reduced rates of oesophagitis and mucositis is glutamine, which is an amino acid (building block of protein) found within high protein foods such as meats, fish, eggs, nuts, beans and milk. As the supplement market is saturated and often confusing, we recommend talking to your oncology dietitian before commencing any supplement. 

What to Eat After Treatment:

As you progress through your treatment and beyond, that Mediterranean style diet is what we want to be aiming for to support our gut health and overall health. 

Here’s some general principle of the Mediterranean diet to keep in mind:

Include oily fish & other omega-3 sources

Rich in anti-inflammatory omega-3 fats, include fish like salmon, mackerel, anchovies and trout. Plant sources of omega-3s include flaxseed, chia seeds and walnuts. 

Include plenty of plants

Wholegrains, vegetables, fruits, nuts, seeds and legumes are all plant foods which are known to have a range of health benefits. As a guide, aim for 30 different types of plants in our diet each week to support gut health and the immune system. 

Include extra virgin olive oil

This oil is a wonderful source of polyphenols (plant chemicals) which have gut-loving and anti-inflammatory properties. Aim for 1-4 tablespoons per day. 

Avoid processed meats

There’s strong evidence that foods such as ham, bacon and sausages are a cause of cancer and the World Cancer Research Fund and American Institute for Cancer Research recommends we avoid these where possible. 

Avoid alcohol

Alcohol is a known cause of many types of cancer and so we recommend avoiding it or keeping intake to a minimum. 


Navigating lung radiotherapy involves more than just medical treatments; it requires a holistic approach that includes dietary considerations. By understanding what to eat before, during, and after treatment, you can actively support your body’s healing process and overall health.

Before, during and after treatment, focus on a Mediterranean-style diet rich in lean proteins, whole grains, colourful fruits and vegetables, nuts, seeds and legumes. These foods support gut health and overall well-being. 

If you’re experiencing radiation-induced oesophagitis, soft and moist foods can help alleviate discomfort, while avoiding trigger foods and extremes in temperature can further ease symptoms. If swallowing becomes difficult, nutritional supplements prescribed by your healthcare team can provide additional support.

Remember, your oncology dietitian is here to guide you every step of the way. Together, we can create a personalised nutrition plan that empowers you to nourish your body and thrive throughout your lung radiotherapy journey. With the right dietary approach and ongoing support, you can face this challenge with strength and resilience.

By combining state-of-the-art radiotherapy techniques with first-class supportive care, we aim to optimise the chance of success of your treatment by reducing side effects and maintaining your quality of life before during and after treatment for lung cancer.