The term "doping" was originally used to describe methods designed to increase the functional efficiency of athletes by means of highly active drugs. Now it is employed to describe any method of improving athletic performance temporarily either during training or in connection with competitive events. Bøje1 has classified such substances into four groups: food preparations, oxygen, artificial sunlight and pharmaceutic substances.
Most of the food preparations, especially dextrose or sugar, which provide calories in a readily acceptable or otherwise suitable form are unobjectionable medically, Bøje feels. The evidence for the use of lecithin is not convincing and there seems to be no reason why it should be recommended for improving athletic performance. Similarly there is no experimental basis on which to recommend the use of yeast, although it does not appear to be deleterious. Conclusive evidence on the role of liver preparations in muscular work and its efficacy for
METHODS USED FOR IMPROVING ATHLETIC PERFORMANCE. JAMA. 1940;115(15):1281-1282. doi:10.1001/jama.1940.02810410047018