Fats provide more favorable effects than carbs from a body composition standpoint for most people.
It was popular in the 60's for many serious bodybuilders to consume protein powders mixed in heavy cream and whole raw eggs. They would also often eat untrimmed steak and tuna in oil, and be able to lean out eating these food sources and avoiding carbohydrates.
Cardio was not a prominent part of contest-prep back then.
Although plenty of guys knew, firsthand, the benefits of Ciba-grade Dianabol, training - and especially diet - were still pivotal.
Many top guys on the West coast followed the dietary instruction of Vince Gironda and Rheo Blair; the bases of their nutrition protocols were quite similar, and maybe one of the few topics the two men actually agreed on.