Ultra-processed foods linked to 67% higher heart attack and stroke risk in US study

A major US epidemiological study has found that people who eat high amounts of ultra-processed foods face a 67 percent higher risk of serious cardiovascular events, including heart attacks and strokes, compared to those who eat the least. The study, published in the Journal of the American College of Cardiology in March 2025, tracked the dietary habits and health outcomes of 27,000 American adults over a 12-year follow-up period, making it one of the largest and longest dietary studies of its kind conducted in the United States.

The threshold that produced the greatest risk was nine or more servings of ultra-processed foods per day. That sounds like a lot until you consider what counts. A bag of chips is one serving. A can of soda is one. A packaged muffin eaten at breakfast, a frozen burrito at lunch, a sports drink in the afternoon, flavored yogurt with added stabilizers, and a ready-made pasta sauce over dinner can collectively cross that threshold without the person eating them thinking of their diet as particularly extreme.

What ultra-processed actually means

The NOVA food classification system, developed by researchers at the University of Sao Paulo and widely used in nutrition epidemiology, places foods into four groups based on the extent and purpose of industrial processing. Ultra-processed foods, the fourth group, are not simply processed. They are formulations made mostly from substances extracted from foods, such as refined starches, hydrogenated oils, and protein isolates, combined with additives including emulsifiers, artificial flavors, and colorants that would not be found in a home kitchen.

The defining characteristic is that ultra-processed foods are engineered to be hyperpalatable, meaning they are specifically designed to be difficult to stop eating, through combinations of fat, sugar, salt, and texture that override normal satiety signals. Whole canned tomatoes are processed. Tomato-flavored chips with sixteen ingredients including modified corn starch and artificial flavor are ultra-processed. The distinction matters because the health outcomes differ, and this study adds to a growing body of research demonstrating that the ultra-processed category carries risks that processed foods without those additives do not.

How the study was designed and what it measured

The research team, based at Tufts University's Friedman School of Nutrition Science and Policy, used data from the NHANES cohort, the National Health and Nutrition Examination Survey, combined with Medicare and Medicaid claims records to track cardiovascular events over the follow-up period. Participants completed detailed 24-hour dietary recall interviews at enrollment, which were used to calculate their daily ultra-processed food intake measured in servings.

The team adjusted for a wide range of confounding variables including age, sex, physical activity levels, smoking history, body mass index, total caloric intake, and socioeconomic status. The 67 percent elevated risk persisted after those adjustments, which is the figure that makes the finding clinically significant rather than a product of lifestyle factors that tend to cluster together in people who eat poorly.

Which foods drove the highest risk

Not all ultra-processed foods contributed equally to cardiovascular risk in the study. Meat-based ultra-processed products, including processed deli meats, hot dogs, and canned meat products, showed the strongest association with heart attack and stroke outcomes, with a hazard ratio of 1.58 compared to the lowest consumption group. Sugar-sweetened beverages showed a hazard ratio of 1.39. Packaged breads, cereals, and savory snacks showed more modest but still statistically significant associations in the range of 1.15 to 1.22.

The researchers also noted that industrial ultra-processed desserts, including packaged cakes, cookies, and pastries, were associated with elevated risk primarily through their effect on fasting blood glucose and triglyceride levels, which the study tracked as biomarker endpoints alongside cardiovascular events.

The biological mechanisms behind the association

Researchers have proposed several biological pathways that may explain why ultra-processed food consumption raises cardiovascular risk. Chronic low-grade inflammation is one. A 2021 analysis in the British Medical Journal found that higher ultra-processed food intake was associated with elevated levels of C-reactive protein, an inflammation marker strongly linked to cardiovascular disease. Gut microbiome disruption is another candidate. Emulsifiers commonly used in ultra-processed foods, including carboxymethylcellulose and polysorbate-80, have been shown in animal studies to alter gut bacteria composition and increase intestinal permeability, which feeds inflammatory cascades.

Sodium content also plays a role. Ultra-processed foods account for approximately 71 percent of total sodium intake in the US diet, according to a 2017 CDC analysis. Elevated sodium intake raises blood pressure, and sustained high blood pressure is one of the most reliable predictors of heart attack and stroke risk. The Tufts team found that the cardiovascular risk association held even after adjusting for total sodium intake, suggesting that the ultra-processed category carries additional risk beyond what sodium alone explains.

How the US compares to other countries on ultra-processed food consumption

Ultra-processed foods account for approximately 57 percent of total caloric intake in the United States, according to a 2016 analysis in BMJ Open. The UK sits at around 54 percent. Canada and Australia are both above 40 percent. By contrast, Italy and Portugal, where traditional Mediterranean dietary patterns remain more common, have ultra-processed food shares below 25 percent of total caloric intake. Those countries also have substantially lower age-adjusted cardiovascular mortality rates, though the comparison involves many variables beyond diet alone.

The United States is particularly exposed because ultra-processed foods are disproportionately affordable and accessible relative to fresh whole foods in lower-income neighborhoods and food-desert communities. A 2022 USDA report found that the cheapest 1,000 calories of food available in low-income US zip codes came almost entirely from ultra-processed sources.

What researchers are asking public health agencies to do

The Tufts research team has formally called on the US Department of Agriculture and the Department of Health and Human Services to incorporate ultra-processing as a specific dietary guideline category in the 2025 to 2030 Dietary Guidelines for Americans, which were under revision when the study was published. The current guidelines focus on nutrients such as saturated fat, sodium, and added sugars, but do not categorically address ultra-processed foods as a distinct food group with its own risk profile.

Brazil updated its national dietary guidelines in 2014 to explicitly recommend avoiding ultra-processed foods, becoming the first country to do so. Chile, Israel, and Canada have since incorporated similar language into their official guidance. The 2025 to 2030 US Dietary Guidelines advisory committee is scheduled to release its final recommendations in December 2025, and the Tufts study will be formally submitted as evidence for the ultra-processed food guideline category.