|Typical protein sources.|
As the participants of this study still gained fat, I would still recommend exercising in order to build muscle; this just shows that you don't have to solely rely on exercise. The type of protein also matters too, i.e. the amino acids, which are the building blocks of proteins. There are around 20 amino acids, but the three branched-chain amino acids are most important for muscle growth, especially leucine. Leucine works with insulin and insulin-like growth factor 1 (IGF-1) to regulate muscle growth, partly by increasing the activity of mTOR, which often carries a negative image. However, mTOR has its place, in the context of building muscle, especially if you need to do this in order to avoid frailty. Additionally, even though I have written in support of lowering IGF-1 through the Paleo Diet, I have also said that increasing it is necessary to speed fracture healing. Context is key, just as you need some cortisol to live. I would also like to add the importance of glutamine, if you have considerably aged biologically or have/had another condition that results in gastrointestinal damage, as we often recommend this to rebuild the gut lining. The contribution of inflammation to age-related muscle loss is another topic for another post; that would be chronic inflammation, not the acute inflammation we often need to fight infection or initiate healing. Antiaging and longevity require control of various factors, not an all-or-nothing approach.