Overview
The goal of this clinical trial is to examine in a 2x2 factorial RCT what feature(s) of ultra-processed foods (UPFs) contribute to cardiometabolic risk in men and women. The project's hypotheses are :
- that the nutrient composition of UPFs (high SFA, free sugar and sodium) per se has deleterious impacts on cardiometabolic risk factors;
- that the industrial techniques and processes of UPFs per se do not.
Participants will be randomly assigned to one of 4 groups consistent with the 2x2 factorial design of the study: 1- the nutrient composition of foods (low vs. high in SFA, free sugar and sodium) and 2- the degree of industrial techniques and food processing (little to no vs.important amounts of UPFs). All foods will be provided to participants under isocaloric conditions during the 6-week dietary intervention. Participants will have to consume one of the 4 experimental diets for 6 weeks.
Description
This study is a parallel group 2x2 factorial randomized controlled trial, in which diet is fully controlled. A total of 120 men and women covering a broad range of adiposity and cardiometabolic risk factors will be randomly assigned to one of four 6-week experimental diets:
- A diet low in saturated fatty acids (SFAs), free sugar and sodium, with low ultra-processed foods (UPFs)
- A diet rich in SFAs, free sugar and sodium, with low UPFs;
- A diet low in SFAs, free sugar and sodium, with high levels of UPFs;
- A diet rich in SFAs, free sugar and sodium, with high levels of UPFs.
All foods in this full-feeding trial will be managed or prepared by food technicians at the Clinical Investigation Unit of our research center. A cyclic seven-day menu plan will be developed with similar foods across the four diets. Classifications of the degree of food processing will be made using NOVA classification. NOVA identifies four categories of foods based on the degree of food processing: 1- Unprocessed or minimally processed foods, 2- Processed Culinary Ingredients, 3- Processed Food and 4- Ultra-processed foods (UPFs). The two diets high in UPFs will predominantly feature commercially-bought foods classified as NOVA-4, while the two diets low in UPFs diets will predominantly include foods prepared in our metabolic kitchen (NOVA 1 to 3). Diets will be provided under isocaloric conditions to maintain body weight constant. The breakfast meal will represent approximately 30% of the daily energy intake in each diet, whereas the lunch and dinner meals each will provide about 35% of daily energy intake. Participants will have to come to the research center 3 to 5 times a week during the 6-week intervention to collect their meals and be weighed. Primary and secondary outcomes will be measured at the beginning and at the end of the 6-wk diet intervention.
The specifics objectives of this 2x2 factorial RCT are:
Obj 1: To assess the impact of the nutrient composition of UPFs on cardiometabolic risk, independent of variations in industrial techniques and processes (factor 1).
Obj 2: To assess the impact of industrial techniques and processes of UPFs on cardiometabolic risk, independent of variations in nutrient composition (factor 2).
Eligibility
Inclusion Criteria:
- Body mass index (BMI):18 to 35 kg/m2
- Stable weight over the last 3 months (variation of less than 5 kg)
- LDL-cholesterol < 5.0 mmol/L
- HbA1c < 6.5%
- Office blood pressure <150/90 mmHg
- Non-smokers or smokers of less than 10 cigarettes a day
Exclusion Criteria:
- Pregnant or breast-feeding women
- Alcohol consumption of more than 7 drinks per week
- Women: contraceptives for less than 3 months or hormone therapy for less than 6 months
- Medication to treat hypercholesterolemia, diabetes or hypertension
- Diagnosis of cardiovascular disease, diabetes, hypertension, cancer
- Food allergies or aversions to any of the foods on the experimental menus
- Being on a diet or following a special diet
- Daytime MAPA blood pressure >150/90