This is the most important macronutrient for repairing and growing muscle tissue. It’s something that Arnie new even before the advent of advanced nutrition science.
The Austrian Oak always recommended anyone who trains hard should be eating 1g of protein for every pound of bodyweight – so for a 180lb man, make sure you’re eating 180g of protein. For Arnie it was 250g.
The main sources of protein for him were lean meats, fish, chicken and eggs. One guideline Arnie suggested in his 1991 article was getting between 30g and 50g of protein in every three hours (depending on your macro needs).
As well as whole foods, he was getting two protein shakes in a day with milk to hit his 250g target.
Arnie knew back then what science has confirmed now – that getting moderate amounts of protein in every three hours is optimal for building muscle.