Researchers from New Zealand and the UK studied data from more than 500,000 children in 50 countries.
They found kids in their early teens who ate fast food at least three times a week had a 39 percent increased risk of severe asthma and other allergy-related conditions.
Six and seven year olds had a 27 percent increased risk.
By the way, researchers also found that eating three or more servings of fruit a week cut the risk of severe asthma and eczema, by as much as 14 percent.
