Luc van Loon

PhD, Extraordinary Professor of Exercise Physiology and Nutrition, Maastricht University Medical Center, The Netherlands

Luc van Loon is a Professor of Physiology of Exercise and Nutrition and Head of the M3-research unit at the Department of Human Biology at Maastricht University Medical Centre. Luc has an international research standing in the area of skeletal muscle metabolism. Current research in his laboratory focuses on the skeletal muscle adaptive response to exercise, and the impact of nutritional and pharmacological interventions to modulate muscle metabolism in health and disease. The main research interests of his laboratory include muscle metabolism, sports nutrition, clinical nutrition, adaptation to endurance and resistance type exercise, and the use of physical activity and/or nutritional interventions to improve health and support healthy aging. The latter are investigated on a whole-body, tissue, and cellular level, with skeletal muscle as the main tissue of interest. Luc has authored more than 300 original, peer-reviewed research and review articles. He is member of the Editorial Board of the International Journal of Sport Nutrition and Exercise Metabolism (IJSNEM) and the European Journal of Sport Science (EJSS). He is a member of the Scientific Board of the European College of Sport Science (ECSS) and the Benelux Association for Stable Isotope Scientists (BASIS). To support the use of stable isotopes in biomedical research, Prof. van Loon is also scientific coordinator of the Stable Isotope Research Center (SIRC) at the Academic Hospital in Maastricht and coordinator of the Human Performance Laboratory at the Departments of Human Biology and Movement Sciences.

Skeletal muscle protein is constantly being synthesized and broken down, with a turnover rate of about 1-2% per day. The rate of skeletal muscle protein synthesis is regulated by two main metabolic stimuli, food intake and physical activity. Food intake, or more specifically protein ingestion, directly elevates muscle protein synthesis rates. The dietary protein derived essential amino acids act as signaling molecules activating anabolic pathways and provide precursors for muscle protein synthesis. Ingestion of a meal-like amount of dietary protein elevates muscle protein synthesis rates for several hours, providing evidence that ‘you are what you just ate’. When food is ingested after a bout of physical activity the post-prandial muscle protein synthetic response is augmented, with higher muscle protein synthesis rates sustained over a more prolonged period of time. In other words, when you ingest protein following a bout of physical activity ‘you become even more of what you just ate’. In contrast, when protein is ingested following a period of inactivity the post-prandial muscle protein synthetic response is blunted, coined anabolic resistance. Therefore, disuse makes you ‘become less of what you just ate’. These concepts play a key role in the prevention and management of sarcopenia.

Quote: “You are what you just ate”

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