[1] Consequently, there is no uniform definition of what constitutes low-protein, because the amount and composition of protein for an individual with phenylketonuria would differ substantially from one with homocystinuria or tyrosinemia.
[2] By studying the composition of food in the local population in Germany, Carl von Voit established a standard of 118 grams of protein per day.
William Cumming Rose and his team studied the essential amino acids, helping to define minimum amounts needed for normal health.
In particular, experiments in model systems in rats, mice, and Drosophila fruit flies have shown increases in life-span with reduced protein intake comparable to that for calorie restriction.
[12][8] Some of the most dramatic effects of calorie restriction are on metabolic health, promoting leanness, decreasing blood sugar and increasing insulin sensitivity.
[14] Low protein diets rapidly reduce fat and restores normal insulin sensitivity to diet-induced obese mice.
[15] Specifically restricting consumption of the three branched-chain amino acids leucine, isoleucine and valine is sufficient to promote leanness and improve regulation of blood glucose.
[22] However, at high protein levels, a net loss of calcium may occur through the urine in neutralizing the acid formed from the deamination and subsequent metabolism of methionine and cysteine.