With the preparations for the Olympics 2016 in Rio came a series of demands to the sports world in terms of attaining optimal physical performance for the many disciplines represented at today’s Olympics. In the light of this, we have focused on the dietary and physiological requirements of a modern Olympic athlete and contrast these with those of ancient Greek and Roman athletes. Our particular emphasis has been on the source of nutrients, historical dietary trends, and the search for the optimal sports diet, that is to say a diet that will ensure the attainment of an athlete’s full potential. In reality, nothing has changed between the ancient and modern athletes. To be optimal, a sports diet should be nutritionally balanced, whilst accommodating the genetic and environmental requirements, the gender and age needs, the demands of the sports discipline, as well as addressing any cultural dietary restrictions.