The current study is a sub-study included in the DIETAPYR2 study (Innovations applied to the Pyrenean beef production to enhance consumer-identifiable meat), a randomized-controlled crossover trial consisting of two experimental periods with a duration of 8 weeks each. Enrolled participants were randomly assigned whether to a Pyrenean beef-based diet or to a Conventional chicken-based diet and were instructed to consume this meat three times per week. The Pyrenean beef is meat from young calves of native breeds, raised mainly on local pastures with a recognized impact in environmental and social sustainability of this rural geographical area. The Pyrenees (mountain range between France and Spain) is an optimal place for the practice of extensive livestock rearing given the richness of forages and the existence of native cow breeds that make use of these natural feedstuffs.~To ensure harmonization in the study, each chef of the 3 selected student accommodation halls was provided with instructions on the cooking methods for chicken and beef and they also received examples of recipes. Cooking methods were breaded, stewed and grilled for beef and breaded, stewed and roasted for chicken.~During the 2 weeks before the first period, researchers contacted with participants and obtained informed consent from them. Then, the first visit was scheduled where the medical history was obtained and the anthropometric measurements, blood pressure (systolic and diastolic) and heart rate measures were undertaken. The day after the first visit, in the morning, a blood, stool and urine sample was collected from participants after an overnight fast. At the time of this visit (period 1), each participant was randomly assigned to Pyrenees beef diet (intervention group) or a conventional chicken-based diet (control group).~Following an 8-week experimental period, participants were invited to perform the same assessments as during the first visit. Afterwards, a 5-week washout period took place to remove the possible residual effects of the first experimental period. Participants were requested not to change their diet or physical activity habits for the 5-week washout period. After the washout period, participants were called again to perform the same assessments during a 3rd visit right before the second experimental period (period 2). During this period those previously on Pyrenees beef diet (intervention group) were crossed to conventional chicken diet (control group) and vice versa. Finally, after the 8 week second experimental period, participants were assessed again as in previous visits.
The DIETAPYR2 study is a randomized controlled crossover trial consisting of two experimental periods each lasting 8 weeks. Enrolled participants were randomly assigned to either a Pyrenean beef-based diet or a conventional chicken-based diet and instructed to consume this meat three times a week.~In the first visit the medical history was obtained and anthropometric measurements, blood pressure (systolic and diastolic) and heart rate were taken. The day after the first visit, in the morning, a sample of blood, stool and urine was taken from the participants after an overnight fast. At the time of this visit (period 1), each participant was randomly assigned to a Pyrenean beef diet (intervention group) or a conventional chicken-based diet (control group).~After an experimental period of 8 weeks, the participants were invited to carry out the same evaluations as during the first visit. Subsequently, a 5-week washout period was carried out to eliminate the possible residual effects of the first experimental period. After the washout period, the participants were called back for the same assessments during a third visit just before the second experimental period (period 2). During this period, those who were previously on a Pyrenean beef diet (intervention group) were crossed with the conventional chicken diet (control group) and vice versa. Finally, after the second 8-week experimental period, the participants were retested as on previous visits.