Diet Quality Versus Processing Level for Cardiometabolic Risk, With Xiaowen Wang, PhD

A new analysis presented at NUTRITION 2026, the American Society for Nutrition's annual meeting held July 25-28 in National Harbor, Maryland, found overall diet quality, rather than food processing level, drove associations with cardiovascular disease (CVD), type 2 diabetes (T2D), and all-cause mortality.¹

A team of investigators led by Xiaowen Wang, PhD, a postdoctoral research fellow in the Department of Nutrition at Harvard T.H. Chan School of Public Health, drew on data from more than 200,000 participants across 3 long-running US cohorts.

“In recent years, there has been tremendous attention on ultra-processed foods, and the common perception is very straightforward: people who eat more ultra-processed foods are more likely to have a higher risk of chronic disease. However, this interpretation may be overly simplistic,” Wang told Patient Care Online. “Food processing and nutritional quality are not the same thing. Many ultra-processed foods such as sugary drinks, processed meats are clearly unhealthy, but others like whole grain bread, fortified breakfast cereals, plant-based dairy, canned beans, canned fruits, and dark chocolate can still provide fiber, vitamins, and other important nutrients. At the same time, some minimally processed foods are not necessarily healthy if they are high in refined carbohydrates or added sugars.”

Because the Nova classification system used to flag ultra-processed foods does not account for nutritional value, Wang and colleagues set out to separate processing level from diet quality. Using the Nurses' Health Study, Nurses' Health Study II, and Health Professionals Follow-Up Study, the team constructed 6 plant-based diet indices reflecting healthy (hPDI) and unhealthy (uPDI) eating patterns, each split into ultra-processed (UPF) and non-UPF versions. The cohort included 160,690 women and 42,585 men free of cancer, CVD, and T2D at baseline.²

Over follow-up, researchers documented 26,209 CVD cases, 21,006 T2D cases, and 55,493 deaths. Both UPF-hPDI and non-UPF-hPDI were significantly associated with lower risk of CVD (hazard ratio [HR], 0.86 and 0.82), T2D (HR, 0.67 and 0.66), and mortality (HR, 0.89 and 0.93), comparing highest with lowest quintiles.¹ Conversely, UPF-uPDI and non-UPF-uPDI predicted significantly higher CVD (HR, 1.17 and 1.21) and T2D risk (HR, 1.11 and 1.14), though only UPF-uPDI reached significance for mortality.¹

Wang cautioned the findings do not endorse ultra-processed foods broadly, since many remain high in added sugars, sodium, and refined carbohydrates. She said clinicians can advise patients to eat more healthy plant foods, including vegetables, fruits, whole grains, legumes, nuts, vegetable oils, while limiting sugary drinks, processed meats, sweets, and highly refined snacks, and to look beyond processing labels toward overall nutrient content when evaluating packaged foods.

References

1. Wang X, et al. Plant-based diets with differential food processing levels and risk of cardiovascular disease, type 2 diabetes, and mortality. Presented at: NUTRITION 2026; July 25-28, 2026; National Harbor, MD.

2. American Society for Nutrition. For long-term health, diet quality matters more than food processing level. EurekAlert! Published July 28, 2026. Accessed July 30, 2026. https://www.eurekalert.org/news-releases/1136477