Big enough dose of ECA significantly reduces hunger on pretty much everyone. You can easily try it on yourself.

Professional athletes undergo years of training, special diets, various legal and illegal performance enhancement, are brainwashed into performing better, and are selected from people genetically predisposed into their sport. That's a long list of differences.

Things like ECA and modafinil work on an average healthy adult.

Also the most interesting athletic performance enhancing drugs don't work on CNS, but to enlarge muscle cells or increase their number (HGH, steroids), increase blood capacity to carry oxygen (EPA), reduce body fat (different steroids), or water (diuretics) etc. CNS-affecting drugs seem to be a minor issue.