Nutrition: Old School vs New School
There is a huge difference in approach to Nutrition today in bodybuilding and fitness compared to the 60s, 70s and 80s 'Classic' or 'Golden' Era. There could be many reasons for this, one invariably being the more detailed discovery of what role nutrients play in our body. One might say that it is this fact alone that over complicates the modern diet and leads to a potentially negative impact on results, others might argue that we now benefit even more from the knowledge, structuring better and more effective diets for ourselves. Either way it seems people had more impressive physiques 'back in the day' then they do now. There are obviously more factors involved here than Nutrition, but let's compare some old school principles to modern principles anyway.
It must be first said that Training alone creates the stimulus for change rather than over emphasis on nutrition. Muscles will not grow unless trained appropriately.
The number one nutrient needed in life, it is required in huge amounts to grow muscles. Without enough Protein you will never grow. As much as 2-3g per pound of body weight is required for best results. Any excess will be used as energy via Gluconeogenesis or discarded as waste any way.
Protein is really important, but you actually don't need very much in order to grow. 1g per pound of body weight is enough (wrong).