What happens to key nutrients when you eat more ultra-processed foods?
The clearest evidence comes from large national surveys that compare the diets of people who eat a lot of UPFs versus those who eat mostly whole or minimally processed foods. A meta-analysis of nationally representative samples found that as UPF consumption increased, intakes of fiber, protein, potassium, zinc, magnesium, and vitamins A, C, D, E, B12, and niacin all decreased, while free sugars, total fat, and saturated fat increased [5]. In practical terms, the more UPFs you eat, the less room you have for nutrient-dense whole foods.
A study of the Australian population found that people in the highest quintile of UPF consumption had significantly lower intakes of vitamins A, E, C, B9, B12, zinc, calcium, iron, magnesium, potassium, and phosphorus, even after adjusting for factors like income and education [8]. Similarly, a study of Brazilian pregnant women showed that higher UPF intake was associated with reduced protein, fiber, iron, zinc, and folate, and increased total fat, saturated fat, trans fat, and free sugar [9]. These patterns are consistent across different countries and populations.
Are all ultra-processed foods equally bad for nutrition?
No, UPFs are a diverse category, and some have a better nutrient profile than others. A market analysis in Germany compared high-protein (HP) UPFs to normal-protein (NP) UPFs and found that HP products had lower sugar, lower total and saturated fat, and higher fiber and protein, earning better Nutri-Score ratings (67% of HP products scored A vs. 22% of NP products) [2]. However, HP UPFs also had higher salt content and more additives, including environmentally persistent artificial sweeteners [2]. So even 'healthier' UPFs come with trade-offs.
A study of UPFs marketed in Italy found that while all products were classified as UPFs, their nutritional composition varied widely — 23% earned a Nutri-Score A or B, while others were high in fat, sugar, or salt [6]. This means that blanket statements about UPFs can be misleading; the specific product matters. However, the overall trend across the food supply is that UPFs tend to be less healthy than their minimally processed counterparts. In Slovenia, UPFs made up 54.5% of available products and had significantly higher sugar, salt, and saturated fat, and lower protein, compared to less processed foods in the same categories [3].
Does the harm go beyond just missing nutrients?
Yes, the evidence suggests that UPFs may cause health problems through mechanisms other than simple nutrient displacement. A large Brazilian study found that people in the highest quartile of UPF consumption had a 28% faster rate of global cognitive decline over 8 years, even after adjusting for overall diet quality [1]. This suggests that something about the processing itself — perhaps additives, altered food matrix, or inflammatory compounds — may be harmful.
Similarly, a study of multiple sclerosis patients found that higher UPF consumption was associated with a nearly 3-fold higher odds of moderate-to-severe disease, independent of overall diet quality [4]. And in the Framingham Offspring Study, each additional daily serving of UPF was linked to a 7% higher risk of cardiovascular disease and a 9% higher risk of cardiovascular death [7]. These associations persist even when researchers account for the poor nutrient profile of UPFs, pointing to additional risks from processing itself.
Sources used in this answer
Association Between Consumption of Ultraprocessed Foods and Cognitive Decline
Higher UPF consumption was associated with a 28% faster rate of global cognitive decline and a 25% faster rate of executive function decline over 8 years in a Brazilian cohort of 10,775 adults.
Nutritional value and environmental aspects of high-protein ultra-processed foods on the German market
High-protein UPFs had lower sugar and fat but higher salt and more additives than normal-protein UPFs; 67% of high-protein UPFs earned a Nutri-Score A versus 22% of normal-protein UPFs.
Ultra-Processed Foods in the Food Supply: Prevalence, Nutritional Composition and Use of Voluntary Labelling Schemes.
UPFs made up 54.5% of the Slovenian food supply and had significantly higher sugar, salt, and saturated fat, and lower protein, compared to less processed counterparts in the same categories.
Ultra-processed foods consumption is associated with multiple sclerosis severity
Higher UPF consumption was associated with a nearly 3-fold increased odds of moderate-to-severe multiple sclerosis after adjusting for confounders.
Ultra-Processed Foods and Nutritional Dietary Profile: A Meta-Analysis of Nationally Representative Samples
In a meta-analysis of national surveys, higher UPF intake correlated with increased free sugars, total fat, and saturated fat, and decreased fiber, protein, and multiple vitamins and minerals.
What Is the Nutritional Composition of Ultra-Processed Food Marketed in Italy?
Among 124 UPFs marketed in Italy, 23% earned a Nutri-Score A or B, showing that UPFs are nutritionally heterogeneous.
Ultra-Processed Foods and Incident Cardiovascular Disease in the Framingham Offspring Study
Each additional daily serving of UPF was associated with a 7% higher risk of hard cardiovascular disease and a 9% higher risk of cardiovascular mortality in the Framingham Offspring Study.
Ultra-processed foods, dietary diversity and micronutrient intakes in the Australian population
In 12,153 Australians, higher UPF consumption was associated with lower dietary diversity and significantly reduced intakes of vitamins A, E, C, B9, B12, zinc, calcium, iron, magnesium, potassium, and phosphorus.
Ultra-processed foods and the nutritional quality of the diet of Brazilian pregnant women.
Among Brazilian pregnant women, higher UPF intake was associated with reduced protein, fiber, iron, zinc, and folate, and increased total fat, saturated fat, trans fat, and free sugar.