The objective of this study is to evaluate the effect of an ultra-processed meal on myocardial endothelial function using positron emission tomography (PET).

The proposed study is an open-label, randomized crossover clinical trial. Participants will be divided into 2 groups: half of the participants will consume a Mediterranean meal during the first experimental visit and an ultra-processed meal during the second, and vice versa for the other half. The order in which the meals will be consumed will be determined randomly.

This project will contribute to clarify the role of diet in the development and progression of coronary artery disease. The results obtained from this study may potentially demonstrate the harmful effect of ultra-processed foods, even in the short term, on coronary arteries.

The proposed study is an open-label, randomized crossover trial. This design will allow participants to serve as their own controls. This is critical as there is some variability in response to vasodilators in the population, and by using this research design, we increase our ability to detect small changes. The study consists of 3 visits: a preliminary visit and two imaging visits. During the preliminary visit, the study will be explained to participants, and consent will be obtained. During the imaging visits, participants will consume a meal, and PET imaging will be completed 4 hours later. Half of the participants will consume the Mediterranean meal during the first visit and the ultra-processed meal during the second visit, and vice versa for the other participants. Randomization will determine the order in which the meals are consumed.

Inclusion Criteria:

1. Men aged between 18 and 50 years.
2. Absence of cardiovascular symptoms.
3. Ability to provide free and informed consent.

Exclusion Criteria:

1. Presence of cardiovascular disease.
2. Active smoking or within the past 12 months.
3. Hypertension (BP > 140/90 mmHg).
4. Renal failure (Creatinine clearance < 90 mL/min).
5. Type I or II diabetes.
6. Dyslipidemia (LDL ≥ 3.5 mmol/L or total cholesterol/HDL ratio ≥ 5.0).
7. Heart failure (Left ventricular ejection fraction < 50%).
8. Congenital heart disease.
9. Obesity (BMI > 35 kg/m2).
10. Uncontrolled asthma or chronic obstructive pulmonary disease (COPD).
11. History of severe allergy or reaction to adenosine or dipyridamole.
12. Second-degree type II or third-degree atrioventricular block.
13. Bradycardia with resting heart rate < 40 bpm.
14. Chronic alcoholism.
15. Substance abuse.
16. Claustrophobia.
17. Vegetarianism.
18. Use of statins or beta-blockers.
19. Food allergy preventing consumption of study meals.
20. Participation in this project would result in cumulative research study radiation dose > 50 mSv in the past 12 months.
21. Neurocognitive disorders or medication use affecting cognition.
22. Any condition that, in the opinion of the investigators, could compromise the subject's participation in the study.

Women excluded to avoir hormonal cycle variation in endothelial function.