According to Gram Research analysis, a 2026 cross-sectional study of 36,669 Brazilian adults found that eating more ultra-processed foods significantly increases the inflammatory potential of your diet. People consuming the most ultra-processed foods had inflammatory diet scores 11 times higher than those eating the least, with each 10% increase in ultra-processed calories raising inflammatory scores by 0.70 points. This strong association suggests that reducing junk food consumption may help lower diet-related inflammation.
A major study of nearly 37,000 Brazilian adults found that eating ultra-processed foods, like packaged snacks, sugary drinks, and fast food, makes your diet more inflammatory. Inflammation is when your body’s immune system overreacts and causes swelling and damage. Researchers used a special scoring system to measure how inflammatory people’s diets were, and discovered that people eating the most junk food had inflammatory scores that were 11 times higher than those eating the least. This connection was very strong and consistent across all the people studied.
Key Statistics
A 2026 cross-sectional analysis of 36,669 Brazilian adults found that people consuming the highest amounts of ultra-processed foods had inflammatory diet scores 11 times higher than those consuming the lowest amounts, with scores of 2.57 versus 0.22 respectively.
According to research reviewed by Gram, each 10% increase in ultra-processed food calories was associated with a 0.70-point increase in the Dietary Inflammatory Index score among 36,669 adults in the NutriNet-Brasil study (2020-2025).
A 2026 study of nearly 37,000 Brazilian adults showed that ultra-processed foods contributed an average of 22.7% of daily calories, ranging from 7.5% in the lowest consumers to 41.1% in the highest consumers.
Research from the 2026 NutriNet-Brasil study demonstrated a linear relationship between ultra-processed food consumption and inflammatory diet potential, with the association remaining statistically significant (p<0.001) even after adjusting for other dietary and lifestyle factors.
The Quick Take
- What they studied: Whether eating ultra-processed foods (packaged snacks, fast food, sugary drinks) makes your diet more inflammatory, which could harm your health
- Who participated: 36,669 Brazilian adults between 2020 and 2025 who shared detailed information about everything they ate over several days
- Key finding: People who got more than 41% of their daily calories from ultra-processed foods had inflammatory diet scores 11 times higher than those eating less than 7.5% ultra-processed foods
- What it means for you: Eating fewer packaged and processed foods may help reduce inflammation in your body, which is linked to diseases like heart disease and diabetes. However, this study shows a connection, not proof that junk food causes inflammation
The Research Details
This was a cross-sectional study, which means researchers looked at a large group of people at one point in time and compared their eating habits to their health markers. The researchers collected information from 36,669 adults in Brazil who participated in the NutriNet-Brasil study between 2020 and 2025. Each person reported what they ate using 2-3 detailed 24-hour food recalls, which is like keeping a food diary for a day and telling researchers everything you consumed.
The researchers then calculated two important numbers for each person: first, what percentage of their daily calories came from ultra-processed foods (things like packaged cookies, soda, instant noodles, and fast food), and second, a special “Dietary Inflammatory Index” (DII) score that measures how much their overall diet promotes inflammation in the body. This DII score is based on the amounts of nutrients, vitamins, minerals, and plant compounds in their diet.
They used statistical analysis to see if people eating more ultra-processed foods had higher inflammatory scores. They organized people into five groups based on how much junk food they ate and compared the groups to each other.
This research approach is important because it looks at real people eating real diets in their everyday lives, rather than a controlled lab setting. By studying such a large group (36,669 people), the researchers could see patterns that might not show up in smaller studies. The cross-sectional design lets researchers identify associations quickly, though it can’t prove that one thing causes another.
This study has several strengths: it included a very large number of people, used detailed food records (24-hour recalls) rather than just asking people to remember what they ate, and controlled for other factors that might affect inflammation like age, exercise, and smoking. However, because it’s cross-sectional, we can’t be certain that ultra-processed foods cause inflammation, only that they’re connected. People who eat more junk food might also have other unhealthy habits we don’t know about. The study was conducted in Brazil, so results might be slightly different in other countries with different food systems.
What the Results Show
The study found a very strong connection between ultra-processed food consumption and inflammatory diet scores. On average, people in the study got about 22.7% of their daily calories from ultra-processed foods. When researchers divided people into five groups based on how much junk food they ate, they found that the inflammatory scores increased steadily as junk food consumption went up.
The difference between the highest and lowest groups was dramatic: people eating the most ultra-processed foods (more than 41% of calories) had inflammatory scores of 2.57, while those eating the least (less than 7.5% of calories) had scores of only 0.22. This means the highest group’s inflammatory score was about 11 times higher. This pattern held true even after researchers adjusted for other factors like age, exercise, and overall diet quality.
When researchers looked at it another way, examining what happens with each 10% increase in ultra-processed food calories, they found that the inflammatory score went up by 0.70 points. This linear relationship (meaning it increases steadily) was statistically significant, meaning it’s very unlikely to have happened by chance.
The study showed that this connection between ultra-processed foods and inflammation was consistent across the entire population studied. There were no major differences based on age or other demographic factors, the pattern held true for different groups of people. This suggests that ultra-processed foods have a pro-inflammatory effect on most people’s diets, not just certain groups.
Previous research has suggested that ultra-processed foods are linked to various diseases where inflammation plays a role, such as heart disease, type 2 diabetes, and obesity. However, the specific connection between ultra-processed food consumption and the Dietary Inflammatory Index hadn’t been thoroughly studied before. This research fills that gap by directly measuring how much junk food consumption affects the inflammatory potential of people’s overall diets. The findings support and expand on earlier research showing that ultra-processed foods are generally unhealthy.
This study shows a connection between ultra-processed foods and inflammatory diets, but it can’t prove that junk food causes inflammation. People who eat more ultra-processed foods might also have other unhealthy habits (like less exercise or more stress) that we don’t know about. The study was done in Brazil, so the results might be slightly different in other countries. Also, people might not remember or accurately report everything they ate, even with detailed food recalls. Finally, the study only looked at people at one point in time, so we don’t know if these patterns continue over years or if changing eating habits would reduce inflammation.
The Bottom Line
Based on this research, reducing ultra-processed food consumption appears to be a practical way to lower the inflammatory potential of your diet. The evidence is strong (high confidence) that eating fewer packaged, processed, and fast foods is associated with less inflammatory diets. A reasonable goal might be to keep ultra-processed foods below 10-15% of your daily calories. This could mean replacing packaged snacks with whole foods like fruits, vegetables, nuts, and whole grains.
This research is relevant for anyone concerned about inflammation-related diseases like heart disease, diabetes, and arthritis. It’s especially important for people with a family history of these conditions. However, this study shows association, not causation, so it shouldn’t replace medical advice from your doctor. People with specific health conditions should consult their healthcare provider before making major dietary changes.
You might notice some benefits from reducing ultra-processed foods within a few weeks (like better energy or digestion), but the anti-inflammatory effects on your body typically take several weeks to months to become noticeable. Long-term benefits for disease prevention would take months to years to measure.
Frequently Asked Questions
What are ultra-processed foods and why do they cause inflammation?
Ultra-processed foods are manufactured products like packaged snacks, sugary drinks, instant meals, and fast food that contain added sugars, unhealthy fats, and artificial ingredients while lacking whole grains, fiber, and nutrients. They promote inflammation because they’re high in inflammatory ingredients and low in anti-inflammatory compounds like fiber and antioxidants found in whole foods.
How much ultra-processed food is safe to eat per day?
This study suggests keeping ultra-processed foods below 10-15% of your daily calories to maintain a less inflammatory diet. For a 2,000-calorie diet, that’s roughly 200-300 calories or about one small packaged snack. However, individual needs vary, so consult a healthcare provider for personalized recommendations.
Can reducing junk food actually reduce inflammation in my body?
This study shows a strong connection between ultra-processed foods and inflammatory diets, but doesn’t prove that eating less junk food reduces inflammation. However, other research suggests that replacing processed foods with whole foods may help reduce inflammation over time, typically within weeks to months.
Does this study apply to people in countries outside Brazil?
The study was conducted in Brazil, so results may vary in other countries with different food systems and eating patterns. However, ultra-processed foods are similar worldwide, so the general finding that they promote inflammation likely applies broadly, though the exact percentages might differ.
What whole foods should I eat instead of ultra-processed foods?
Replace ultra-processed foods with whole foods like fresh fruits and vegetables, whole grains, legumes, nuts, seeds, and minimally processed proteins like chicken or fish. These foods are high in fiber, vitamins, minerals, and anti-inflammatory compounds that help reduce diet-related inflammation.
Want to Apply This Research?
- Track the percentage of your daily calories from ultra-processed foods. Log meals for 3-5 days per week and categorize each food as whole/minimally processed or ultra-processed. Aim to reduce this percentage from your current level by 5-10% each month.
- Replace one ultra-processed food you eat daily with a whole food alternative. For example: swap packaged cookies for fresh fruit, soda for water, or instant noodles for homemade pasta with vegetables. Track this swap in the app to build the habit.
- Weekly check-in: Calculate your average ultra-processed food percentage. Monthly review: Look for trends and celebrate reductions. Quarterly assessment: Note any changes in how you feel (energy, digestion, inflammation markers if you track them). Set a goal to reduce ultra-processed foods by 10% every quarter.
This research shows a connection between ultra-processed food consumption and inflammatory diet patterns, but does not prove that ultra-processed foods directly cause inflammation or disease. Individual responses to dietary changes vary. This article is for educational purposes only and should not replace professional medical advice. Before making significant dietary changes, especially if you have existing health conditions or take medications, consult with your healthcare provider or registered dietitian. The findings are based on a Brazilian population and may not apply equally to all groups.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.
