Scientists have found children who eat a diet rich in fruit, vegetables and fish have a lower risk of asthma and wheezing.
However, eating three or more burgers a week can increase the risk.
Researchers examined data from 50,000 children aged eight to 12, from 20 different countries, collected between 1995 and 2005. And parents were asked if their children had ever been diagnosed with asthma or suffered wheezing.
The experts found that although diet did not increase the risk of allergies to grass and tree pollen but did have an effect on asthma and wheeze. Also, kids on a Mediterranean diet - of fish, veggies and fruits - faced a lower risk of developing asthma.
According to The Independent, the authors wrote, "Fruit and vegetables contain antioxidants and other biologically active factors which may contribute to the favourable effect of fruit consumption in asthma.
"In particular, foods rich in vitamin C have been reported to relate to better lung function and fewer asthma symptoms."
The carotenoids and vitamins C and E in fruit and vegetables was good for lung function.
The study is published in the journal Thorax.