This is an issue which has been gnawing at my subconcscious for a while. Why bodybuilders are so keen on animal-derived protein? They always insist on lean beef or, alternatively, chicken. All other things being equal, the same amount of plant-based protein should provide an equal growth. But it is not like that. Bodybuilders would eat whatever satisfies their desire for larger muscles; if tofu or tempeh would show to bring about bigger muscles, we can be sure they would be eating soy products like mad. They don't though. Experience has thought them. They are not advocates for paleo nutrition, they are simply muscle-building machines. So what it is?
In teh recent podcast featuring Valter Longo and Rich Roll, the latter asks the former what's in animal protein which is so detrimental to health. surprisingly, Valter Longo does not answer straight away, he says it's not very clear.
So, I did one simple thing. I plotted a few animal and plant-based foods according to their contgent of Leucine (mTor activator) and Methionine (IGF-1 activator). The graph is very eloquent. I chose either 100 gr portions (beef, chicken, tofu, salmon, pumpernickel bread) or other significant quantities (250 ml milk).
Beef, chicken, salmon, overwhelm the Leucine and methionine content of plant-based food. Tofu is well below a half the Leucine of lean beef and chicken, with one quarter the methionine.
Is it so simple? I mean, is the above difference enough to justify the stronger anabolic effect of animal based protein? Maybe so, together with the fibreous matrix of plant-based protein which may make'em less available and the known, lowest availability of protein in green leaves (low Jones' factor).
Of course, the higher anabolic effect means easier overamplification of mTOR activity and consequent aging and cancer hazard (plus other factors like pro-inflammatory agents, TMAO and so on).
Tofu and soymilk remain very good plant-based protein sources for those who wish to grow muscles on a vegan diet. Soymilk surprisingly has the same Leu content of cow milk, with half the meth content.
Some portions may be not too meaningful, so suggestions are welcome to change quantities and make foods more directly comparable.
Last but nto least, Leu and meth might not be the only amminoacids responsible, although the role of Leucine as a necessary signaling factor for mTOR phosporylation is well known.
Edited by mccoy, 27 May 2018 - 12:28 PM.