Scientists to investigate whether processing itself makes ultra-processed foods harmful

The controlled-diet trial aims to settle one of the biggest questions in nutrition science: Are UPFs harmful because of how they are made, or what they contain?

A paper was recently published in the journal Contemporary Clinical Trials The protocol for the randomized controlled trial was described (RCT) is designed to investigate how specific characteristics of ultra-processed foods are (UPF) affect cardiometabolic risk.

UPF Has become increasingly prevalent in diets around the world. Meta-analytic evidence suggests that high UPF Its consumption increases the risk of cancer and heart disease (cvd), diabetes, and mortality. Despite increasing research UPFThe characteristics associated with their adverse health effects remain unclear. Some suggest that food alteration and industrial processes are responsible for its dangerous effects. UPF.

poor nutritional profile of UPF This may explain their adverse effects on cardiometabolic risk. A scientific advisory for 2025 cites a lack of consensus about all UPF Cardiovascular health is a concern. It also underlined the need to independently evaluate different UPF dimensions, such as industrial processing and nutrient content. Therefore, to identify the underlying factors of its adverse effects UPF Important to inform public health policies.

UPF trial design and participant criteria

In the current study, researchers presented a protocol for 2 × 2 factorial RCT how to check UPF Control cardiometabolic risk. The first factor is the degree of industrial processing UPF According to NOVA definitions, and the second is nutrient composition. The primary objective of the test is to analyze the personal effects of industrial processing UPF On their nutrient content on cardiometabolic risk in healthy adults. The authors estimate that some have high saturated fat, added sugar, and sodium content. UPF Cardiometabolic risk factors will increase, while the degree of industrial food processing itself will not.

Participants will be recruited from the research center through social media advertisements and electronic newsletters. Eligible participants will be people aged 18-75, with a body mass index (bmi) between 18 kg/m2 and 35 kg/m2, stable weight, low-density lipoprotein cholesterol (LDL-C) <5 mmol/L, blood pressure (BP) < 150/90 mmHg, and glycated hemoglobin (HbA 1C) <6.5%.

a person suffering from diabetes, cvdhigh blood pressure, or cancer, and people who are taking medicines for it BP Reduction, lipid lowering, or diabetes, will be excluded. People who are pregnant or breastfeeding, consume alcohol more than seven times per week, have relevant food allergies or dislikes, or follow a diet that may limit compliance will also be excluded. Participants will be randomized to consume less UPF A diet low in saturated fat, added sugars and sodium (SFSS), a low UPF high diet SFSSa high UPF low diet SFSSor a high UPF high diet SFSS For six weeks.

Controlled diet and outcome measures

A cyclical seven-day daily menu standardized at 2,500 kcal was developed for each diet, matching proteins (15% kcal), carbohydrates (50% kcal), and fat (35% kcal). Each item on the menu was classified into one of four groups of the NOVA classification: Group 1—minimally processed or unprocessed foods; Group 2-Processed culinary ingredients; Group 3-Processed foods; Group 4-UPF.

high UPF The diet primarily consists of commercial foods classified as NOVA Group 4, such as flavored yogurt, oatmeal raisin cookies, waffles, spaghetti with pre-packaged sauce, and ready-to-eat coleslaw. Lower UPF The diet consists primarily of custom-prepared dishes and foods classified as NOVA Group 1-3, such as plain yogurt with maple syrup and frozen fruit, spaghetti with homemade sauce, homemade oatmeal raisin cookies, and pancakes.

Participants will visit the study cafeteria on two or three weekdays for supervised food intake and collect meals/snacks for the remaining day and the following day. They will abstain from consuming alcohol, probiotics, natural health products, artificially sweetened beverages and fiber supplements during the study period. Dietary compliance will be assessed daily using self-reported checklists. Blood lipids, glucose and insulin will be measured at baseline and after the intervention.

Primary outcomes included change from baseline LDL-Cdaytime ambulatory systolic BP (dtSBP), and the homeostatic assessment model of insulin resistance (HOMA-IR) at the end of the intervention. Secondary outcomes included triglycerides, apoB-100, high-density lipoprotein cholesterol (HDL-C), 24 hour ambulatory systolic BP24 hour ambulatory diastolic BPdaytime diastolic BPInsulin, and glucose.

In addition, questionnaires will be administered to examine perceived food healthfulness, dietary palatability, perceived hunger and satiety, dimensions of eating enjoyment, and physical activity. Dual-energy X-ray absorptiometry scanning will be performed to assess body composition and fat at the beginning and end of the intervention. Mixed models will be used to analyze the data, following an intention-to-treat approach.

Implications for UPF nutrition policy

In short, the proposed RCT It will be helpful to know the characteristics of UPF responsible for their adverse health effects, advancing current knowledge and helping policy makers better engage UPF In future guidelines. RCT It has several strengths: its factorial design, sample size, and controlled feeding conditions enable disentangling individual effects UPF On cardiometabolic risks from their industrial processing. However, because the diet is provided under isocaloric conditions to maintain body weight, the test will not directly test this. UPF Ad libitum feeding conditions may lead to excess calorie intake or weight gain.