A bodybuilder like Charles Atlas or Arnold Schwarzenegger would not have been caught dead drinking protein shakes in the glory days of bodybuilding (i.e., the 1970s/1980s); they preferred real foods, and Atlas was a strong proponent of a milk-heavy diet (and even advocated for a milk-only diet during bulking phases). https://physicalculturestudy.com/2014/12/08/charles-atlass-s...

Thus, 40 years ago (i.e., 1980), using protein powder for weight loss/body composition wasn't a big market. Herbalife created that market. GNC and others started selling protein powders for weight loss and bodybuilding after Herbalife proved the viability of the niche. (Note: protein powder is the cheapest form of protein...today. It wasn't back then. It was comparatively quite expensive. In the 80s, beef and chicken were far cheaper than protein powder.)

If you want to debate exercise history you will want to pick a fight with someone who doesn't have GNC and other health companies as clients...