Majerčák Ivan is Senior lecturer at Faculty of Medicine P.J.Šafárik Univeristy in Košice, Slovakia, Cardiologist at Medical group Košice s.r.o. and Nuclear and Molecular Medicine Institute in Košice and Head of the Center for Obesity Treatment, Faculty of Medicine, UPJŠ Košice. In addition he serve as director of non-profit organisation League against obesity, exclusive representative of STOB Praha, Czech Republic in Slovakia. He received his Medical doctor degree from P.J. Šafárik University Faculty of Medicine, Master of Public Health degree from PPA Business School, Paris and University of Secure Management in Košice. His Diploma thesis focused on Life Style Medicine. Doctor Majerčák holds certification from Slovak Medical University in Bratislava for Internal Medicine and Cardiology and from Cognitive Behavioral therapy ABC Institute in Liptovský Mikuláš for cognitive-behavioral psychotherapy with final thesis focused on childhood obesity cognitive-behavioral therapy. Doctor Majerčák Ivan is specialist in Internal Medicine, Cardiology, Obesitology and Cognitive behavioral treatment. His research is focused on the psychological and psychophysiological corellates of obesity and cardiovascular diseases, autonomic nervous system and heart rate variability. He is co-author of APVV project Psychological and psychophysiological correlates of cardiovascular diseases, Slovak research and development agency, Ministry of Education, Research, Development and Youth of the Slovak republic. He work as co-author on Ministry of Health of the Slovak republic guidelines : Standard preventive, diagnostic and therapeutic procedures. Majerčák´s teaching activities are focused on Preventive medicine, Internal medicine, Cardiology, Obesitology and Cognitive-behavioral therapy. As the exclusive representative of STOB Praha, Czech Republic, he trains lecturers for weight loss courses. As a prinicipal investigator he led his study team in more than 60 clinical trials.