Two New Studies Examine the Health Impacts of Ultraprocessed Foods
Cognitive and Dementia Risk Study
Methodology
A study published in Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring analyzed data from over 2,100 Australian adults aged 40–70.
Participants completed food diaries and cognitive tests at the study's start. No participants had been diagnosed with dementia at that time.
Key Findings
Each 10% increase in daily UPF consumption was associated with a 0.24-point increase on a 0–7 dementia risk scale, which estimates 20-year risk.
The increase in UPF intake was also linked to measurable declines in attention and processing speed.
Importantly, this association persisted among participants who followed a Mediterranean diet. This suggests the effect may be related to food processing methods rather than simply the displacement of healthier foods.
Context and Previous Research
According to data from the U.S. Centers for Disease Control and Prevention (CDC), UPFs account for approximately 53% of calories consumed by U.S. adults and 62% by U.S. children.
Previous studies have associated high UPF intake with increased risks of:
- Cardiovascular disease
- Obesity
- Diabetes
- Depression
- Cognitive decline
A January 2024 study reported that a 10% increase in UPF intake was associated with a 16% higher risk of cognitive impairment. Conversely, replacing UPFs with whole foods over 5–6 years was associated with a 12% reduction in cognitive decline risk.
An April 2024 study found that adults in their 50s and 60s who reduced consumption of unhealthy foods over a decade had an 11% lower risk of Alzheimer's disease and dementia.
Researcher Statements
Lead author Barbara Cardoso (Monash University) stated that UPF consumption was associated with worse attention and higher dementia risk in middle-aged and older adults, and noted that this association persisted regardless of adherence to a Mediterranean diet.
Dr. W. Taylor Kimberly (Harvard Medical School), senior author of a related study, commented that the body of research consistently associates higher UPF consumption with poorer cognitive performance.
Metabolic Health Study in Older Adults
Study Design
Published in Clinical Nutrition, this study enrolled 36 U.S. adults aged 65 and older, many of whom had metabolic risk factors such as insulin resistance or high cholesterol.
Participants followed two distinct diets low in UPFs for eight weeks each:
- One included lean red meat
- The other was vegetarian with milk and eggs
For a two-week period between these interventions, participants reverted to their usual diets.
In the low-UPF diets, these foods accounted for less than 15% of total calories, compared to typical U.S. diets where they often exceed 50%. Researchers prepared and provided all meals and snacks using minimally processed ingredients consistent with U.S. Dietary Guidelines. The study did not include instructions for calorie restriction, weight loss, or changes in physical activity.
Key Findings
When participants consumed fewer UPFs, they naturally consumed fewer calories, resulting in weight loss, including reductions in total and abdominal body fat.
Additional observed changes included:
- Improvements in insulin sensitivity
- Healthier cholesterol levels
- Fewer indicators of inflammation
- Favorable alterations in hormones involved in appetite and metabolism regulation
These changes were observed across both the meat-based and vegetarian dietary approaches.
Significance and Limitations
UPFs account for over half of the calories consumed by most U.S. adults. Previous research has linked high consumption of these foods to obesity and age-related chronic conditions including Type 2 diabetes and heart disease.
The study is described as the first to demonstrate that a realistic reduction in UPF intake for older adults can yield measurable health benefits beyond weight loss.
However, the study involved a small number of participants. It was not structured to determine if the observed metabolic improvements can prevent or delay diseases over an extended period. Larger, longer-duration studies are needed to address this question.
Practical considerations remain, including whether individuals can sustain reduced UPF intake in daily life without structured support. Specific aspects of food processing that might be most impactful for health require further investigation.