Physiological, metabolic and molecular adaptations to exercise and a very low-carbohydrate dietary intervention in healthy physically active adults Other
Conditions
Interventions
Following screening, familiarization and baseline assessments, participants will be randomly allocated to one of two dietary intervention groups:
1. Very low-carbohydrate diet (VLChD) providing less
Sponsors
Universidad de Las Palmas de Gran Canaria
Eligibility
Sex/Gender
All
Age
18 Years to 35 Years
Inclusion criteria
Inclusion criteria: 1. Healthy male and female adults aged 18 to 35 years 2. Physically active individuals performing regular exercise training at least 3 times per week 3. Body mass index between 18.5 and 29.9 kg/m² 4. Free from diagnosed cardiovascular, metabolic, respiratory, neuromuscular, or endocrine disease 5. Non-smokers and not taking medications or supplements known to affect metabolism, exercise performance, or hormonal responses 6. Willingness to comply with the prescribed dietary intervention and all experimental procedures 7. Ability to perform maximal exercise testing and repeated muscle biopsy/blood sampling and other physiological assessment procedures 8. Written informed consent provided
Exclusion criteria
Exclusion criteria: 1. History of cardiovascular, metabolic, pulmonary, renal, hepatic, endocrine, or neuromuscular disorders 2. Current smoking or use of recreational drugs 3. Current use of medications or nutritional supplements affecting substrate metabolism, appetite regulation, hormonal function, coagulation, inflammation, or exercise performance 4. Use of hormonal contraceptives in female participants 5. Pregnancy or breastfeeding 6. Body mass index =30 kg/m² or clinically significant underweight 7. Clinically significant anaemia, iron deficiency requiring treatment, abnormal coagulation, or abnormal screening blood results considered incompatible with study participation 8. Musculoskeletal injury, surgery within the previous 6 months, or any limitation preventing maximal exercise testing 9. Known food allergies, dietary restrictions, or intolerance that could interfere with compliance with the prescribed diets 10. Inability or unwillingness to undergo muscle biopsy, blood sampling, femoral arterial/venous catheterization, carbon monoxide rebreathing, DXA, or other physiological assessment procedures 11. Contraindication to maximal exercise testing, femoral arterial/venous catheterization, local anaesthesia, muscle biopsy, DXA, or carbon monoxide rebreathing 12. Failure to comply with pre-study standardization requirements or with the prescribed dietary intervention 13. Any medical condition or investigator-assessed circumstance that could compromise participant safety, adherence to the protocol, or data quality
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Leg respiratory quotient (RQ) during submaximal cycling exercise at 50% VO2max measured using femoral arteriovenous oxygen and carbon dioxide content differences, from which RQ is calculated according to the Fick principle at the acute invasive trial, after glycogen depletion and 3 days of dietary intervention; and the post-training invasive trial, after 2 weeks of sprint interval training | — |
Secondary
| Measure | Time frame |
|---|---|
| Leg respiratory quotient (RQ) during submaximal cycling exercise at 65% VO2max measured using femoral arteriovenous oxygen and carbon dioxide content differences, from which RQ is calculated according to the Fick principle at the acute invasive trial, after glycogen depletion and 3 days of dietary intervention; and the post-training invasive trial, after 2 weeks of sprint interval training;Skeletal muscle signalling responses to exercise measured using immunoblotting (Western blotting) of vastus lateralis muscle biopsy samples, assessing AMPK, p38 MAPK, CaMKII, Nrf2/Keap1 and ACE2/Ang-(1-7)/MasR-related targets at baseline before the dietary intervention; during the acute invasive trial after glycogen depletion and 3 days of dietary intervention (at rest before exercise, 10 seconds after completion of the functional reserve test, and 30 minutes after completion of the full exercise protocol); and during the post-training invasive trial after 2 weeks of sprint interval training (same timepoints);Mitochondrial and oxidative capacity responses to exercise measured using high-resolution mitochondrial respirometry of vastus lateralis muscle biopsy samples at baseline before the dietary intervention; during the acute invasive trial after glycogen depletion and 3 days of dietary intervention (at rest before exercise and 10 seconds after completion of the functional reserve test); and during the post-training invasive trial after 2 weeks of sprint interval training (same timepoints);Muscle glycogen content and distribution measured using biochemical glycogen assays and transmission electron microscopy of vastus lateralis muscle biopsy samples (with additional exploratory proteomic, metabolomic and molecular analyses on stored samples subject to supplementary funding availability) at baseline before the dietary intervention; during the acute invasive trial after glycogen depletion and 3 days of dietary intervention (at rest before exercise, 10 seconds after completion of the | — |
Countries
Spain
Contacts
Public ContactMarcos Martín Rincón
Outcome results
None listed