Here is where we left off last week: “next week we will examine the specific mechanisms by which the researchers suggest may explain the link between high-protein intake and increased mortality. Warning: it may get complicated!”
Here is the bottom line- protein encourages growth. That is why pregnant women are encouraged to eat protein (growth of the fetus), why children should eat protein (so they grow), and why fitness professionals recommend protein intake (to encourage muscle growth).
Protein synthesis is reduced 15-30% following an overnight fast (depending on the length of the fast); while muscle protein synthesis is increased 20-50% after a meal (depending upon the size/composition) (Lowery and Antonio). This increase is due to the direct effect that amino acids (specifically leucine) has on the cellular machinery responsible for building muscle tissue. This is pretty clear cut.
The issue gets sticky, however, in the presence of existing disease. If there is malignant tissue present, it may also be stimulated to grow. This is obviously not good.
So what can you do? The best advice is to exercise, eat real food, manage your stress, and have faith that your body, given the right stimuli, has the innate wisdom to allow the appropriate tissue to grow, while destroying malignant tissue.
To conclude, this whole issue is what makes periodic intermittent fasting a potentially attractive option, as caloric restriction is linked to longevity in animal studies. When one goes through short periods of caloric deprivation, particularly protein-deprivation, the body initiates a process called ‘autophagy’, in which damaged proteins are recycled to provide raw materials for the construction of new proteins (again, this occurs in the absence of dietary protein consumption).
Notice I said ‘periodic’ and ‘short-periods’. That is all.
Lowery LM and J Antonio. Dietary Protein and Resistance Exercise (2012). CRC Press, Boca Raton, FL.