According to Gram Research analysis, a 2026 cohort study of 1,754 families found that eating a Western diet—high in processed foods and sugar—during pregnancy and early childhood increases childhood asthma risk, with the strongest effect in lower-income families. Children whose mothers followed this dietary pattern had significantly higher rates of asthma and wheezing by age 10, suggesting that diet quality during pregnancy and infancy may be a preventable risk factor for childhood asthma.
A new study of nearly 600 families found that eating a Western diet—full of processed foods, sugar, and unhealthy fats—during pregnancy and a child’s early years increases the risk of asthma and wheezing. Interestingly, this risk was strongest in families with lower income and education levels. Researchers used blood tests to track what mothers ate and followed children until age 10 to see who developed asthma. The findings suggest that diet quality during pregnancy and infancy matters for children’s lung health, especially for families with fewer resources.
Key Statistics
A 2026 cohort study of 1,754 mother-child pairs found that Western dietary patterns during pregnancy and early childhood were associated with increased childhood asthma and wheezing risk, with effects strongest in families with lower socioeconomic status.
Research reviewed by Gram found that socioeconomic status inversely correlated with Western diet consumption (correlation coefficient -0.40 to -0.14), meaning lower-income families ate more processed foods, and their children had higher asthma risk from this dietary pattern.
In the COPSAC2010 cohort of 594 families, the association between Western diet and childhood asthma was significantly stronger in low-socioeconomic-status children compared to higher-income children, suggesting diet quality disparities contribute to asthma health inequalities.
The Quick Take
- What they studied: Whether eating a Western-style diet (lots of processed foods, fast food, and sugary items) during pregnancy and early childhood increases the chances a child will develop asthma, and whether family income affects this risk.
- Who participated: Nearly 1,750 pregnant women and their children from three different research groups in Europe and the United States. Researchers tracked what mothers ate during pregnancy and measured children’s health until age 10.
- Key finding: Children whose mothers ate a Western diet during pregnancy and early childhood had a higher risk of developing asthma or wheezing. This risk was especially strong in families with lower household income and less parental education.
- What it means for you: Eating healthier during pregnancy and a child’s first few years—with more fruits, vegetables, and whole foods instead of processed items—may help prevent asthma. This appears especially important for families with limited resources who may rely more on affordable processed foods.
The Research Details
Researchers followed 594 mother-child pairs from one study group (COPSAC2010) and verified their findings in two additional groups with 772 and 388 families. Mothers filled out detailed food questionnaires during pregnancy, and children were checked for asthma and wheezing until age 10. Scientists also analyzed blood samples taken during pregnancy and when children were 6 and 18 months old to identify chemical markers linked to Western diet eating patterns.
The researchers used a special statistical method to connect what mothers ate to specific chemicals found in their blood. They then looked at whether these dietary patterns predicted asthma risk. They also measured family socioeconomic status—a combination of household income, mother’s education level, and mother’s age—to see if this affected the diet-asthma connection.
This approach is powerful because it combines actual food intake records with biological markers (blood chemicals) and real health outcomes (asthma diagnosis). By studying multiple groups, the researchers could confirm their findings weren’t just a fluke in one population.
Understanding how diet affects asthma risk is important because asthma is one of the most common chronic diseases in children. If diet during pregnancy and early childhood influences asthma development, it suggests a preventable cause. The focus on socioeconomic status matters because lower-income families may have less access to healthy foods, meaning dietary interventions could help reduce health inequalities.
This study is relatively strong because it followed real families over time (rather than just comparing groups at one point), used multiple study populations to confirm findings, and measured both diet and biological markers. However, the study is observational, meaning researchers watched what happened rather than randomly assigning people to eat different diets. This means we can’t be completely certain that diet alone caused the asthma risk—other factors could be involved. The findings are from European and North American populations, so results may differ in other parts of the world.
What the Results Show
In the main study group, families with lower socioeconomic status ate more Western-style foods (processed items, fast food, sugary drinks) compared to higher-income families. Children whose mothers followed a Western diet during pregnancy and early childhood had significantly higher rates of asthma and wheezing by age 10. The risk was strongest in children from lower-income families.
When researchers looked at blood chemicals, they found specific metabolites (breakdown products of food) that were linked to Western diet eating patterns. These same metabolites were associated with higher asthma risk. Importantly, the connection between diet and asthma was stronger in lower-socioeconomic-status families than in higher-income families.
The findings held up when tested in two additional study groups with different populations, suggesting the pattern is real and not just a coincidence in one group. The researchers found that socioeconomic status didn’t just modify the effect—it appeared to be a key factor in how diet influenced asthma development.
The study found that the timing of diet exposure mattered. Both pregnancy diet and diet during the child’s first 18 months showed connections to asthma risk. Blood metabolite patterns at different time points (pregnancy, 6 months, and 18 months) all reflected the Western diet pattern and predicted asthma outcomes. This suggests that early life nutrition—from before birth through infancy—is a critical window for asthma development.
Previous research has linked Western diets to asthma risk in general, but this study adds important new information by showing that socioeconomic status plays a major role. Earlier studies suggested that diet quality matters for asthma, but didn’t clearly explain why lower-income families seemed to have higher asthma rates. This research suggests that limited access to healthy foods in lower-income communities may be a key mechanism. The use of blood metabolites to confirm dietary patterns is a newer, more objective approach than relying only on food questionnaires.
The study is observational, so we cannot prove that diet directly causes asthma—other factors like air pollution, infections, or genetics could be involved. Mothers reported their own food intake, which may not be perfectly accurate. The study focused mainly on European and North American families, so findings may not apply to other populations with different food systems and asthma rates. The researchers measured socioeconomic status using income, education, and age, but other factors like food access or stress weren’t directly measured. Finally, while the study found associations with asthma diagnosis, it didn’t explain exactly how Western diet chemicals affect the lungs.
The Bottom Line
Pregnant women and families with young children should aim to eat more whole foods like fruits, vegetables, whole grains, and lean proteins, and limit processed foods, fast food, and sugary drinks. This recommendation has moderate-to-strong evidence from this and other studies. The evidence is particularly important for lower-income families who may benefit most from dietary improvements. However, families should recognize that diet is just one factor affecting asthma risk; genetics, environment, and infections also play roles.
Pregnant women planning pregnancy, parents of young children, and families with a history of asthma or allergies should pay special attention to these findings. Lower-income families may benefit most from dietary improvements, though everyone can benefit from healthier eating. Healthcare providers working with pregnant women and young children should consider discussing diet quality as part of asthma prevention. Policymakers should note that improving food access in lower-income communities could reduce childhood asthma rates.
Changes in diet during pregnancy may influence asthma risk that appears in early childhood (by age 3-5 years). If a family improves their diet now during pregnancy or early childhood, benefits may take several years to become apparent, as asthma typically develops gradually. Long-term dietary habits matter more than short-term changes.
Frequently Asked Questions
Does eating junk food during pregnancy cause asthma in babies?
A 2026 study of 1,754 families found that mothers eating Western-style diets (processed foods, fast food, sugar) during pregnancy had children with higher asthma rates by age 10. While this suggests a connection, diet is one of many factors affecting asthma risk, including genetics and environment.
What is a Western diet and why does it increase asthma risk?
A Western diet means lots of processed foods, fast food, sugary drinks, and unhealthy fats—foods low in nutrients. Research shows these foods may trigger inflammation in the body and affect how the immune system develops in the womb and during infancy, potentially increasing asthma susceptibility.
Does socioeconomic status affect how diet influences asthma?
Yes. A 2026 study found that lower-income families ate more Western-style foods and their children had stronger connections between diet and asthma risk. This suggests limited food access in lower-income communities may increase asthma rates through poor diet quality.
What should pregnant women eat to prevent asthma in their children?
Focus on whole foods: fruits, vegetables, whole grains, lean proteins, and healthy fats. Limit processed foods, fast food, sugary drinks, and ultra-processed items. While no diet guarantees asthma prevention, research shows healthy eating during pregnancy and early childhood supports better respiratory health.
When does asthma develop if a mother eats unhealthy during pregnancy?
Asthma typically develops gradually during early childhood, often appearing by ages 3-5 years. The study followed children until age 10 and found higher asthma rates in those exposed to Western diets in pregnancy and infancy, suggesting early-life nutrition is critical.
Want to Apply This Research?
- Log daily food intake during pregnancy and early childhood, specifically tracking servings of processed foods, fast food, and sugary drinks versus whole foods (fruits, vegetables, whole grains). Set a goal to reduce Western diet items by 20% each month and increase whole foods by the same amount.
- Replace one processed food or fast food meal per day with a home-cooked meal using whole ingredients. Start with breakfast or lunch, whichever is easiest. Track which meals you swap and how you feel. Gradually increase to two meals per day over a month.
- Weekly food diary review to identify Western diet patterns. Monthly assessment of grocery shopping habits and meal planning. Track any respiratory symptoms in children (coughing, wheezing) alongside dietary changes. Share food logs with healthcare provider at prenatal and pediatric visits to discuss dietary improvements.
This research shows an association between Western dietary patterns and childhood asthma risk, but does not prove diet alone causes asthma. Asthma development involves multiple factors including genetics, environment, infections, and immune system development. This information is for educational purposes and should not replace professional medical advice. Pregnant women and parents concerned about asthma risk should consult with their healthcare provider about personalized dietary and health recommendations. If your child shows signs of asthma (persistent coughing, wheezing, shortness of breath), seek medical evaluation promptly.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.