High-Fat Meals and Asthma: What a Fast-Food Study Found

A single high-fat, fast-food style meal increased airway inflammation and blunted the effect of a rescue inhaler in people with asthma, according to a small 2011 trial from the University of Newcastle in Australia. A much larger global survey of children and teens also linked frequent fast food to more severe asthma symptoms. Neither proves that fat causes asthma, but together they suggest diet is worth paying attention to.

This guide explains what both studies found, their limits, and practical eating tips for people with asthma. For more, see our asthma guides.

Jump to: Quick answer · The high-fat meal trial · The global fast food study · Limits · Practical tips · FAQ

Quick answer

• More airway inflammation: 4 hours after a high-fat meal, people with asthma had more inflammatory cells (neutrophils) in their sputum than after a low-fat meal.
• Weaker inhaler response: lung function improved less after the bronchodilator (albuterol-type rescue medicine) following the high-fat meal.
• Type of fat mattered: a meal high in trans fat raised airway neutrophils more than one without trans fat.
• Fast food and severe asthma: in a worldwide survey, eating fast food 3 or more times a week was linked to higher odds of severe asthma; eating fruit 3 or more times a week was linked to lower odds.
• Keep your medicines and action plan; diet is an add-on, not a replacement.

The high-fat meal trial

In the 2011 study in the Journal of Allergy and Clinical Immunology, researchers at the University of Newcastle randomly assigned non-obese adults with asthma to a high-fat meal (19 people; 48% of calories from fat) or a low-fat meal (18 people; 15% fat). They measured lung function before and 2, 3 and 4 hours after a bronchodilator, and checked airway inflammation in sputum.

The authors concluded that a high-fat meal increased neutrophilic airway inflammation, depending on the type of fat, and suppressed bronchodilator recovery, and that changing dietary fat intake may be useful in asthma.

The global fast food study

Phase Three of the International Study of Asthma and Allergies in Childhood (ISAAC), published in Thorax in 2013, surveyed 13- to 14-year-olds and parents of 6- to 7-year-olds around the world about diet and symptoms.

• Fast food 3 or more times a week was linked to higher odds of severe asthma: 39% higher in teens and 27% higher in younger children. It was also linked to severe hay fever-type symptoms and severe eczema.
• Fruit 3 or more times a week was linked to lower odds of severe asthma: about 11% lower in teens and 14% lower in children.

The authors noted that if the link is causal, it would matter a lot for public health, given rising fast food consumption worldwide.

Limits of the research

• The meal trial was small and measured effects over only 4 hours after a single meal.
• The survey was observational, based on questionnaires, so it shows associations, not cause and effect.
• Diet is one of many factors; allergens, infections, pollution and medicine use all affect asthma control.

Practical tips for people with asthma

1. Don’t skip or change asthma medicines because of diet; follow your action plan. See our asthma FAQ.
2. Limit fast food and fried, high-fat meals, especially before exercise or when your asthma is flaring.
3. Avoid trans fats, which raised airway inflammation more in the trial.
4. Eat fruit regularly; it was linked to lower odds of severe asthma.
5. Talk to your doctor or a dietitian about an eating pattern that fits your health needs.

For more on food and allergies, see diet for allergy sufferers. Other everyday asthma triggers: spray cleaners and ozone.

This guide is general information, not medical advice. Read our medical disclaimer.

Frequently asked questions

Can a high-fat meal make asthma worse?

In a small trial, a high-fat meal increased airway inflammation and reduced the response to a rescue inhaler over the next 4 hours, compared with a low-fat meal.

Does fast food cause asthma?

Not proven. A global survey linked eating fast food 3 or more times a week to higher odds of severe asthma in children and teens, but it can’t show cause and effect.

Are some fats worse than others for asthma?

In the Newcastle trial, a meal high in trans fat raised airway inflammation more than a meal without trans fat.

What foods may help asthma?

The global survey linked eating fruit 3 or more times a week to lower odds of severe asthma. Diet should complement, not replace, asthma treatment.

Should I stop eating fat if I have asthma?

No need to cut all fat. Limiting fast food, fried foods and trans fats is a reasonable step. Ask your doctor or a dietitian for advice.

Sources

• Wood LG, Garg ML, Gibson PG. A high-fat challenge increases airway inflammation and impairs bronchodilator recovery in asthma. J Allergy Clin Immunol. 2011;127(5):1133-1140.
• Ellwood P, Asher MI, García-Marcos L, et al. Do fast foods cause asthma, rhinoconjunctivitis and eczema? Global findings from the International Study of Asthma and Allergies in Childhood (ISAAC) phase three. Thorax. 2013;68(4):351-360.

Last reviewed: October 21, 2026.