Actual, observable results are evidence that X or Y works and that science may or may not be able to explain yet.
Gravity existed long before Newton.
Going upstream against irrefutable truths is stupid but let's be honest, few hard facts, genuine facts, exist in the kinesiology/nutritional world where universal application is concerned. Results exist, however. Like gravity did, before Newton described it. Disregarding actual results because a study doesn't exist to "prove" the result in a lab setting is also stupid.