Too much protein can lead to increase in liver enzymes, kidney problems and leaky gut. High protein diets lead to high urinary creatinine while low protein dieting leads to urine saturated with citric acid.
A deficiency in protein leads to muscle atrophy, impaired immune system and weaker bones. Dietary protein intake was shown to be inversely associated with risk of stroke in women with hypertension. Lean animal protein like fish showed most protective benefit.