A study of more than 500,000 children across the world has found a link between eating fast food and conditions such as asthma and eczema.
Professor Innes Asher from the University of Auckland in New Zealand and Professor Hywel Williams from the University of Nottingham in Britain looked at the data on global disease and dietary patterns.
They say the data from children in 51 countries suggests poor diet may be to blame for rising levels of allergy-related conditions.
Those who ate more than three servings a week of fast food such as such as take-away burgers, fries and pizzas were more prone to wheezing, runny noses, watery eyes and itchy skin - symptoms of conditions such as asthma, conjunctivitis and eczema.
Professor Asher says the results don't prove cause and effect, but hopes the study will help convince people that fast food should only be eaten in moderation.
The study's authors say eating plenty of fruit appears to be protective. Their findings have been published in respiratory medicine journal Thorax, the official journal of the British Thoracic Society.
A New Zealand health expert says the research is a compelling argument for the negative effects of fast food.
Kyle Perrin, a respiratory physician and medical adviser for the Asthma and Respiratory Foundation, says further research is needed to prove the link.
"But if this association is true and the public health implications are quite major and it puts even more emphasis behind the fact that we really need to control the consumption of fast food - not just for obesity, but for allergic disease as well."
Dr Perrin says the study could have major implications for public health in New Zealand and worldwide.