Ultra-processed foods are a major part of modern diets, especially in places like the United States, where they make up almost 60% of the average person’s daily calories.
These foods are often convenient and tasty, but they are made mostly from substances that have been heavily altered from their original form—such as fats, starches, added sugars, and oils. Many also include artificial colors, flavors, and preservatives to improve their shelf life and appearance.
Examples of ultra-processed foods include frozen dinners, soft drinks, packaged snacks, instant noodles, fast food, sweetened breakfast cereals, and processed meats like hot dogs and deli meats.
While they are popular for their convenience and flavor, a growing body of research has found that eating a lot of these foods can be harmful to your health. Past studies have linked them to obesity, cancer, heart disease, inflammatory bowel conditions, and even early death.
Now, a new study has found that these foods may also be bad for your brain. Researchers recently discovered that eating too many ultra-processed foods is linked to a faster decline in brain function, especially as people age.
The study was conducted as part of the Brazilian Longitudinal Study of Adult Health, which followed over 10,000 adults over time to look at changes in their health.
In this study, the team focused on how much ultra-processed food each person ate and how their brain function changed over time.
The results were concerning. People who got more than 20% of their daily calories from ultra-processed foods—about 400 calories in a typical 2,000-calorie diet—experienced a 28% faster decline in overall brain performance and a 25% faster decline in executive function, which includes skills like planning, decision-making, and self-control.
Although the study does not prove that ultra-processed foods directly cause cognitive decline, the link is strong enough to raise concern. Dr. David Katz, one of the study’s authors, noted that there are several reasons to believe these foods might play a role in speeding up brain aging.
Ultra-processed foods tend to be high in added sugars, unhealthy fats, and salt, but low in fiber and nutrients. This kind of diet can lead to inflammation, poor blood sugar control, and other health problems that may also harm the brain.
It’s also important to note that ultra-processed foods contribute nearly 90% of the added sugars in the American diet, which may further increase the risk of brain decline. These foods may also displace more nutritious choices, like fruits, vegetables, whole grains, and healthy fats—foods that have been shown to support brain health.
While more research is needed to understand exactly how ultra-processed foods affect the brain, this study adds to growing concerns about the long-term impact of a diet high in packaged and processed items.
For people looking to protect their brain health as they age, cutting back on ultra-processed foods and eating more whole, nutrient-rich foods may be a smart move.
The study, conducted by Dr. David Katz and colleagues, was published in JAMA Neurology and is part of a larger effort to understand how lifestyle factors influence brain health over time.
If you care about dementia, please read studies about low choline intake linked to higher dementia risk, and how eating nuts can affect your cognitive ability.
For more information about brain health, please see recent studies that blueberry supplements may prevent cognitive decline, and results showing higher magnesium intake could help benefit brain health.
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