Justyna Mizera, MA, is a sports nutritionist, and since 2009 she has balanced over 1,100 diets for athletes in various sports. She works with, among others, 30 world championship medalists and Olympians, but also with obese adults and children. She has competed in body fitness competitions. Author of numerous scientific and popular-science articles. She appears as an expert source for television stations. She also teaches courses in dietetics. Krzysztof Mizera, PhD, is a sport physiologist and personal trainer. He works with leading athletes and amateurs in training, weight loss, improving motor skills, performance, and nutrition. Since 2008 he has been a lecturer at various universities. Mizera has contributed to numerous scientific projects and conferences. His doctoral thesis dealt with the nutrition in athletes. He is the author of over 120 publications and the bestseller Running Is Simple.