When preparing for a marathon, diet is often seen primarily as a source of energy or a way to improve recovery. Its connection with respiratory health is less commonly considered.
Yet the overall quality of our diet can influence various mechanisms involved in how the body functions and in lung health. With just a few weeks to go before the Marathon des Alpes-Maritimes Nice-Cannes, Dr Raphaëlle Varraso, an epidemiologist at IHU RespirERA, sheds light on this still relatively overlooked connection.
When we think about respiratory health, smoking and pollution usually come to mind. Why should we also consider diet?
Smoking and air pollution are major determinants of respiratory health, but they are not the only ones. Throughout our lives, the health of our lungs is influenced by numerous environmental, behavioural, social and biological factors.
Diet is part of this environment. It is still too often overlooked when we talk about lung health, even though it affects several mechanisms involved in respiratory diseases, including inflammation, oxidative stress, immune response, the gut microbiome and metabolism.
Our research therefore suggests that what we eat may also contribute to the health of our lungs. The aim is clearly not to replace the essential messages about smoking and pollution, but to gain a better understanding of all the factors that may support or preserve respiratory health.
Key takeaway: diet complements other preventive measures; it does not replace them.
Can what we eat really affect the health of our lungs?
Diet is, of course, not the only factor, and it cannot replace treatment, physical activity or smoking prevention. Nevertheless, numerous epidemiological studies show that a higher-quality diet is associated with better respiratory health.
Associations have notably been observed with asthma symptoms and with the risk of developing chronic obstructive pulmonary disease, or COPD.
This does not mean that a single food directly protects or damages the lungs. What matters more is our overall diet and the eating habits we develop over time, which may help create a biological environment that is more or less favourable to respiratory health.
Key takeaway: the effect does not depend on a single meal or food. It develops over time through the habits we build in our daily lives.
Is there a diet that is particularly beneficial for respiratory health?
There is no miracle food that can help us breathe better. What appears to matter most is the overall quality of our diet and the role played by plant-based foods.
Studies suggest that a diet rich in minimally processed plant-based foods is associated with better respiratory health outcomes. The Mediterranean diet provides a useful reference point: it prioritises fruit and vegetables of all colours, pulses, wholegrains, nuts, olive oil and fish, while limiting foods high in sugar, processed meats and ultra-processed foods.
However, simply “eating plant-based” is not enough. A diet may be predominantly plant-based while still being high in refined, sugary or ultra-processed products. Both the proportion and the quality of plant-based foods therefore matter.
This type of diet offers another potential benefit: it may also be better for the planet. Giving a greater place to plant-based foods and limiting certain foods, such as red and processed meats and ultra-processed products whose production has a significant environmental impact, may help reduce the environmental footprint of our diet. This connection between human health and the health of the planet lies at the heart of the concept of a “planetary health diet”.
In practice: aim for a varied daily diet rich in minimally processed plant-based foods — fruit and vegetables of all colours, pulses, wholegrains and nuts — while limiting highly refined products, processed meats and ultra-processed foods.
Can ultra-processed foods really affect respiratory health?
Under the NOVA classification, ultra-processed foods are products that have undergone several stages of industrial processing and often contain ingredients or additives that are rarely used in home cooking. Examples include certain sugary drinks, industrially prepared meals, biscuits and snack foods, some highly sweetened breakfast cereals and industrially produced desserts.
Recent epidemiological studies suggest that a high consumption of ultra-processed foods may be associated with a greater risk of chronic respiratory diseases, particularly COPD. The evidence is currently more consistent for COPD than for asthma, for which the available data remain limited.
Key takeaway: ultra-processed foods are not solely responsible for these diseases, but they are one aspect of diet that deserves further investigation. The aim is not to pursue a perfect diet or make people feel guilty, but to choose fresh or minimally processed foods as often as possible and limit the consumption of ultra-processed products.
Why are charcuterie and other processed meats receiving particular research attention?
Processed meats are meats that have undergone processes such as salting, curing, fermentation or smoking, particularly to improve their preservation or flavour. Charcuterie represents a major category of these products and may contain nitrites or nitrates. These compounds may promote nitrosative stress, a mechanism which, together with oxidative stress and inflammation, could contribute to damage to lung tissue.
Several epidemiological studies have examined the relationship between the consumption of charcuterie and other processed meats and respiratory health. For COPD, a meta-analysis of five prospective studies involving nearly 290,000 people suggests that higher consumption is associated with a greater risk of developing COPD: every additional 50 g consumed per week was associated with an approximately 8% higher risk.
In our own research, we also found an association with COPD in the Nurses’ Health Study II. Women who regularly consumed processed meats had a higher risk of COPD. When several unfavourable factors were present — smoking, processed meat consumption and a lower-quality diet — the risk was more than six times higher than among women who had none of these factors.
We have also studied asthma. In the French EGEA study, adults who consumed at least four portions of processed meat per week had an approximately 76% higher risk of experiencing worsening asthma symptoms during follow-up. This finding was subsequently replicated in the NutriNet-Santé study, where high processed meat consumption was associated with more asthma symptoms.
Key takeaway: these results do not mean that charcuterie or other processed meats alone cause asthma or COPD. They suggest that their consumption may be one dietary factor among others to consider when seeking to preserve respiratory health.
higher risk of COPD associated with each additional 50 g of processed meat consumed per week in a meta-analysis.
higher risk of worsening asthma symptoms associated with consuming at least four portions per week in the EGEA study.
For runners, what is the practical link between diet, breathing and marathon preparation?
Diet will not instantly improve a runner’s respiratory capacity. However, it contributes to the proper functioning of the body as a whole, including energy availability, muscle function, recovery, immune defences and metabolic health.
During exercise, the respiratory and cardiovascular systems must deliver the oxygen the muscles need to produce energy. Endurance performance therefore depends on all these systems working together effectively.
A balanced diet will not, by itself, enable someone to run faster or farther overnight. It can, however, help create the right conditions for regular training, recovery between sessions and long-term health.
Key takeaway: diet complements other preventive measures; it does not replace them.
Advice before race day
Do not make sudden, major changes to your habits: race day is not the time to experiment.
4 key principles to remember before race day
- Do not look for a miracle food.
- Prioritise variety and minimally processed foods.
- Limit the place of ultra-processed foods in your diet.
- Test foods and drinks during training.
Marathon preparation also starts on your plate
When preparing for a marathon, diet should not be considered solely from the perspective of immediate performance. It contributes to energy availability, muscle function, recovery and, more broadly, overall and respiratory health.
Epidemiological research suggests that a varied, high-quality diet rich in minimally processed plant-based foods is associated with better respiratory health outcomes. Conversely, high and repeated consumption of certain products, particularly processed meats such as charcuterie and ultra-processed foods, may be associated with a greater risk of respiratory disease.
The aim is not to pursue a perfect diet or to feel guilty about eating a particular food occasionally. What matters is building habits over time that support long-term health.
Because preparing for a marathon involves your legs, your breathing and your recovery — but also what you put on your plate every day.
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