In one of the first studies to examine the link between ultra-prcessed food consumption and how the body processes glucose in young people, USC researchers found that an increase in UPF intake was associated with a higher risk for prediabetes, or early-stage high blood sugar that can lead to diabetes. Eating more UPFs was also linked to insulin resistance, where the body becomes less effective at using insulin to control blood sugar. The research included 85 young adults from the Metabolic and Asthma Incidence Research (Meta-AIR) study, part of the broader Southern California Children's Health Study. Participants, aged 17-22, provided data at a baseline visit between 2014 and 2018 and a follow-up visit approximately four years later. At each visit, participants reported everything they had eaten on one recent weekday and one recent weekend day. Researchers classified foods into two categories: UPFs (such as candy, soda, cereal, packaged spreads, flavored yogurts, and many restaurant foods) and foods that were not ultra-processed. They then calculated what percentage of each participant’s daily caloric intake came from UPFs. The researchers also collected blood samples from participants before and after they consumed a sugary drink to test how effectively their body responded to blood sugar with insulin. They then conducted a statistical analysis to compare dietary changes with signs of prediabetes, adjusting for differences in age, sex, ethnicity and physical activity levels. From baseline to follow-up, a 10% increase in UPF consumption was associated with a 64% higher risk for prediabetes and a 56% higher risk for problems with glucose regulation. Participants who reported eating more UPFs at their initial visit were also more likely to have elevated insulin levels at follow-up—an early sign of insulin resistance, where the body must produce more insulin to keep blood sugar in a healthy range