It's no secret that processed foods, while cheap and convenient, are terrible for our health.
The worst offenders - ultraprocessed foods filled with preservatives and added sugar - have been linked to a higher risk of heart disease and premature death, according to a study published last month in the American Journal of Clinical Nutrition.
A group of Italian researchers followed 24,325 men and women age 35 and older for up to 10 years, collecting data on their eating habits and health outcomes.
They found that participants who ate plenty of ultraprocessed foods had a higher risk of dying from cardiovascular disease, heart attack, or stroke than those who did not. The more processed foods they ate, the greater the increase in risk, the data found.
Participants who consumed the most, in this study, ate at least 15% of their daily calories in the form of ultraprocessed food, and up to 50%. That's between 300 to 1,250 calories a day worth of processed food for most people, or the equivalent of 2-8 servings of hot dogs, candy bars, soda, or the like.
People in that category were 58% more likely to die of cardiovascular disease during the study than their peers who consumed the least ultraprocessed food (no more than approximately one serving a day) They were also 52% more likely to die of stroke or another type of cerebrovascular disease.
The most common forms of ultraprocessed food in the Italian study were pizza, snack cakes and pies, and processed meats (including anything cured or smoked, such as bacon and sausages).
But the definition also includes some surprising examples, like granola or flavored yogurt, that may appear to be healthy at first glance.
That's because ultraprocessed food refers to any edibles that are packaged in a ready-to-eat format, produced in factory with thickeners, preservatives, coloring, and other additives. They're likely to contain high-fructose corn syrup, protein isolates, processed seed oils, and other ingredients to maintain flavor and keep them shelf-stable for long periods of time.
Other examples of ultra-processed foods include candy, soda, snack bars, manufactured baked goods such as bread, margarine, energy drinks, hot dogs, and chicken nuggets.
Previous research has found that ultraprocessed food tends to be highly palatable, meaning it can make us hungrier and encourage overeating.
Researchers in this most recent study theorized that sugar played a major role in the risk associated with ultraprocessed foods. Consuming too much sugar has previously been linked to health issues including heart disease, obesity, and diabetes. Evidence also suggests that artificial sweeteners may pose similar health risks.
But neither sugar nor other ingredients like saturated fat could totally explain the health risks, meaning we still don't fully understand why ultraprocessed food is so dangerous.
More research is needed to better understand what's behind the health risks of ultraprocessed foods. What we do know, however, is that swapping to minimally-processed foods seems to help reduce those risks.
These include whole foods like fresh fruits and vegetables, unprocessed lean meats, whole grains, and healthy sources of fat like olive oil and avocado.