RE: Early pre contest diets??
Vince Gironda used a diet many moons ago that utilised carb restriction and refeed every fourth day.
He would have his athletes consume no carbs just meat and eggs for 3 days straight and every fourth day have a refeed.
His athletes were so ripped that in contests they were deemed to be "freaky" and over the top with regards to definition.
Google maximum definition diet. Iirc thats what it was called.