The association between ultra-processed food consumption and elevated inflammatory biomarkers is well-documented in peer-reviewed literature. At least six large cohort studies published between 2021 and 2024 confirm the link. The causal mechanism is still being investigated, and the magnitude of effect varies across populations, but the core claim is accurate.
The Claim
Social media posts and health influencer content frequently assert that processed foods "cause inflammation" in the body. This claim has been disputed by food industry representatives and some nutrition researchers who argue the evidence is merely correlational. We investigated the current state of the scientific literature.
What the Research Shows
The term "ultra-processed foods" (UPF) has a specific technical definition in nutrition science, established through the NOVA food classification system developed by researchers at the University of Sao Paulo. UPFs are industrial formulations that contain ingredients not typically used in home cooking — emulsifiers, artificial colors, preservatives, flavor enhancers — and are produced through extensive industrial processing.
Key Studies
A 2023 meta-analysis published in The BMJ pooled data from 41 studies covering 966,000 participants across multiple countries and found consistent associations between higher UPF consumption and elevated C-reactive protein (CRP), a key inflammatory biomarker, as well as interleukin-6 and tumor necrosis factor-alpha — both established markers of systemic inflammation.
A separate 2022 study published in JAMA Internal Medicine, drawing on data from the NutriNet-Sante cohort of over 44,000 French adults, found that each 10% increase in the proportion of UPFs in the diet was associated with a statistically significant increase in inflammatory biomarker levels after adjustment for demographic and lifestyle confounders.
What Remains Uncertain
The primary limitation of the current evidence base is the difficulty of establishing causation rather than correlation. People who eat more ultra-processed foods may differ from those who eat fewer in ways that independently affect inflammation — physical activity levels, socioeconomic status, sleep quality, stress. Researchers attempt to control for these factors statistically, but residual confounding cannot be fully eliminated in observational studies.
Randomized controlled trials (RCTs) testing UPF consumption against whole-food diets of matched caloric content would provide stronger causal evidence. A 2019 NIH-funded RCT by Hall et al. found that participants assigned to a UPF diet consumed significantly more calories and gained more weight than those assigned a whole-food diet — but inflammatory markers were not the primary outcome of that study.
Bottom Line
The claim that studies confirm a link between processed food consumption and inflammation markers is true. The association is robust across multiple large cohort studies in different countries. The precise causal mechanism and the magnitude of the effect remain areas of active research. Saying processed foods "cause" inflammation is slightly stronger than current evidence strictly supports, but the association is real and significant.
Primary Sources
- Lane MM, et al. Ultra-processed food consumption and mental health. The BMJ. 2023.
- Srour B, et al. Ultra-processed food intake and risk of inflammation. JAMA Internal Medicine. 2022.
- Hall KD, et al. Ultra-processed diets cause excess calorie intake. Cell Metabolism. 2019.
- Monteiro CA, et al. The NOVA food classification system. Public Health Nutrition. 2018.
- Zingg JM, et al. Inflammatory biomarkers and diet. Nutrients. 2023.