Diet quality drives cardiometabolic risk, ultra-processed or not

Clinical takeaway: Steer patients toward nutrient-dense foods and away from added sugars and refined carbs. In any form, whole grains, vegetables, nuts, and legumes were tied to lower risk of heart disease, diabetes, and death.

Counseling patients on ultra-processed foods has become one of the trickier conversations in primary care. Headlines say to avoid them, but the category sweeps in whole-grain breads and plant-based milks alongside soda and packaged desserts. New data from three large Harvard cohorts suggest a cleaner message: what determines risk is the nutritional quality of the diet, and that held at every processing level studied.

Processing level and nutritional quality often work in tandem, which makes them hard to untangle. Many ultra-processed foods are high in added sugars, sodium, and refined carbohydrates, so heavy UPF intake tends to mean a poor diet. But the overlap isn't complete: fortified cereals, whole-grain products, canned beans, and plant-based dairy are all classified as ultra-processed, while white rice, fruit juice, and homemade desserts made with refined flour count as minimally processed.

Healthy plant-based diets were associated with a 14% to 18% lower risk of cardiovascular disease and roughly a third lower risk of type 2 diabetes, whether built from ultra-processed or minimally processed foods. This was based on comparing the highest with the lowest quintiles of adherence. Mortality followed suit, at 7% to 11% lower.

Unhealthy plant-based diets, patterns weighted toward refined grains, sugary drinks, and sweets, ran the other way: 17% to 21% higher CVD risk and 11% to 14% higher diabetes risk at both processing levels. Mortality was the one place processing mattered: ultra-processed unhealthy eating carried a significantly higher risk, at 7%, while minimally processed unhealthy eating showed no significant increase.

The analysis drew on three long-running US cohorts, the Nurses' Health Study, Nurses' Health Study II, and the Health Professionals Follow-Up Study, following about 203,000 adults free of cancer, CVD, and diabetes at baseline from the mid-1980s through the early 2020s. Researchers scored each participant's plant-based diet quality, then classified the plant foods using the Nova classification system, which groups foods by how industrially processed they are, yielding six diet indices to compare.

Over follow-up, they documented 26,209 CVD cases, 21,006 diabetes cases, and 55,493 deaths. The findings were presented at NUTRITION 2026 and have not yet undergone journal peer review.

The authors noted that dietary guidance should continue to center proven high-quality patterns, Mediterranean or healthy plant-based, instead of elevating processing level as a marker of healthy eating. They also pointed to reformulation to improve the nutritional content of packaged foods as a way to make quality diets easier to follow.

"Advising people to universally 'avoid ultra-processed foods' can lead to lower diet quality since healthy ultra-processed foods are beneficial and unhealthy minimally-processed foods are detrimental," said Xiaowen Wang, PhD, a postdoctoral research fellow in the Department of Nutrition at Harvard T.H. Chan School of Public Health.

Source: Wang X, et al. (2026 Jul 28) NUTRITION 2026, American Society for Nutrition Annual Meeting. Plant-Based Diets With Differential Food Processing Levels and Risk of Cardiovascular Disease, Type 2 Diabetes, and Mortality