Researchers have identified biological markers in blood and urine that may reveal how much ultraprocessed food (UPF) a person consumes, offering a more objective tool to study diet-related health risks, according to a new study published in PLOS Medicine.

Led by Erikka Loftfield of the National Cancer Institute, the study is the first to pinpoint specific metabolites—byproducts of digestion—that correlate with higher intake of UPFs like sodas, chips, and frozen meals. These foods, which make up nearly 60% of the American diet, are associated with numerous health issues, but difficult to track through self-reported dietary data.

Using samples from more than 700 older U.S. adults, researchers developed a set of 28 blood and 33 urine markers that reliably predicted UPF consumption. The method was validated using data from a controlled 2019 NIH study, where participants alternated between UPF-heavy and unprocessed diets.

Some markers, including two amino acids and a carbohydrate, appeared frequently across tests and were linked to increased risk of type 2 diabetes. The findings could help scientists explore how different UPFs and additives affect health.

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Dr. Dariush Mozaffarian of Tufts University, who was not involved in the study, called it a "major scientific advance" that could eventually guide more targeted research on the health effects of food processing.

Loftfield hopes to apply the tool in broader studies to examine links between UPF intake and diseases such as cancer—but emphasized the need for more research funding to support this work.

“There’s growing scientific and public interest in understanding whether—and how—ultraprocessed foods impact health,” she said.