Ultra-Processed Foods and Inflammation: What NHANES Data Shows

Americans now get about 55% of their daily calories from ultra-processed foods, according to a 2025 report from the U.S. Centers for Disease Control and Prevention. A separate analysis published that same year in The American Journal of Medicine found that people who eat the most of those foods carry significantly higher blood levels of an inflammation marker called high-sensitivity C-reactive protein (hs-CRP). The study used federal nutrition data, and the pattern held up after researchers accounted for age, BMI, smoking, and physical activity.

For anyone living in Maine or New Hampshire, where long winters make convenience food an easy fallback and where adult obesity rates have been climbing for decades, the findings are worth understanding.

What Counts as Ultra-Processed

The research used the NOVA classification system, a framework developed in 2009 by Brazilian epidemiologist Carlos Monteiro that sorts foods by how much industrial processing they’ve undergone. Group 4, the ultra-processed category, includes foods made mostly or entirely from substances extracted from whole foods, with little intact food remaining. Soft drinks, packaged snacks, reconstituted meat products, instant soups, and most breakfast cereals fall here.

Minimally processed foods, such as pre-washed salad mixes, canned beans, or plain frozen vegetables, sit in a different group entirely. The distinction matters because NOVA focuses on the degree and purpose of processing, not just fat or sugar content.

What the NHANES Analysis Found

The study, led by E. Martínez Steele and colleagues, drew on data from 9,254 adults in the U.S. National Health and Nutrition Examination Survey (NHANES). Participants were grouped by what share of their total calories came from ultra-processed sources, from the lowest tier (under 20%) to the highest (60-79%).

Those in the top tier had significantly higher hs-CRP than those in the bottom tier. The association followed a dose-response pattern, meaning elevated inflammation tracked with increasing ultra-processed food consumption across the middle groups as well. Minimally processed convenience foods showed no such link.

hs-CRP is a protein the liver releases in response to inflammation. Chronically elevated levels are associated with higher cardiovascular risk and other systemic health problems. It’s one of the markers clinicians use alongside cholesterol and blood pressure when evaluating a patient’s long-term risk picture.

Why Processing Matters, Not Just Ingredients

One of the older debates in nutrition science is whether ultra-processed foods are harmful because of what’s in them (added sugar, sodium, saturated fat) or because of something about the processing itself. The NHANES findings add to a growing body of evidence suggesting processing plays an independent role.

Several proposed mechanisms are being studied. Ultra-processed foods tend to disrupt the gut microbiome, which plays a role in regulating immune responses — a topic covered in depth in our guide to gut health basics and what research supports. Many contain emulsifiers, artificial colorings, and flavor compounds that may affect the gut lining. They’re also typically low in fiber and polyphenols, both of which appear to have anti-inflammatory effects in clinical research — a reason why wild foods like those covered in Maine’s fall foraging guide to mushrooms and berries are worth understanding from a nutritional standpoint.

None of this means every packaged food is dangerous. A bag of frozen edamame is technically processed. The NOVA framework is specific: it’s the industrial reformulations, not all convenience foods, that drive the association.

Putting It in Context for New England

Maine’s adult obesity rate stood at 31% as of 2020 BRFSS data, and the state has seen steady increases over the past two decades, according to America’s Health Rankings. Obesity and systemic inflammation are closely connected, and dietary patterns are a primary driver of both.

This doesn’t mean the solution is a dramatic overhaul. The NHANES analysis suggests a dose-response relationship, which implies that incremental changes matter. Swapping a few highly processed items for minimally processed alternatives, without aiming for perfection, may shift inflammatory markers in a meaningful direction over time. That’s a more useful frame than an all-or-nothing approach, particularly for households managing cost and convenience in rural areas. For a practical starting point, the Portland farmers markets seasonal nutrition guide covers which local whole foods are available by time of year. Residents interested in the broader dietary strategy can also find region-specific guidance in our practical guide to anti-inflammatory eating in Northern New England.

Sources

• Martínez Steele E, et al. Ultra-processed foods and increased high sensitivity C-reactive protein. The American Journal of Medicine. 2025. https://www.amjmed.com/article/S0002-9343(25)00549-2/abstract
• U.S. Centers for Disease Control and Prevention. Obesity and Severe Obesity Prevalence in Adults: United States, August 2021-August 2023. NCHS Data Brief No. 508. https://www.cdc.gov/nchs/products/databriefs/db508.htm
• NPR / CDC. Ultra-processed food consumption is down a bit, but still more than 50% of U.S. diet. August 2025. https://www.npr.org/sections/shots-health-news/2025/08/07/nx-s1-5495308/ultra-processed-food-upf-rfk-cdc
• America’s Health Rankings. Obesity in Maine. https://www.americashealthrankings.org/explore/measures/Obesity/ME
• Monteiro CA, et al. The NOVA food classification system. Public Health Nutrition. 2018. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10260826/

This article is for informational purposes only and does not constitute medical advice. Consult a qualified healthcare provider before making any health decisions.