This randomized controlled trial will examine the effects of within-day protein distribution and leucine supplementation on body composition, physical performance, and biomarkers of muscle damage in tactical athletes during an 8-week intensive training program. Sixty-nine healthy male participants (18-35 years) enrolled in a Ministry of Defense training course will be randomly assigned to one of three iso-caloric dietary groups providing 1.6 g/kg/day of protein: (1) evenly distributed protein across three meals (EVEN), (2) a 16-hour daily protein fasting pattern with protein concentrated at lunch and dinner (FAST), or (3) the same fasting pattern with 5 g leucine supplementation at breakfast (FAST-RESCUE).
Primary outcomes include changes in lean body mass. Secondary outcomes include strength, anaerobic performance, and biochemical markers of muscle damage, including urinary titin N-terminal fragment (UTF). Assessments will be conducted at baseline, Week 5, and Week 8.
Male participants aged 18-35 years
Enrolled in an active Ministry of Defense tactical training program
Physically active and medically cleared to participate in intensive training
Willing and able to comply with the dietary intervention and training protocol
Musculoskeletal or neuromuscular injury or impairment limiting participation in exercise training
Cardiopulmonary disease (including recent myocardial infarction or unstable angina)
History of cancer, diabetes, thyroid disease, hypertension, or chronic renal failure
Cognitive impairment affecting ability to provide informed consent