When you consume a balanced meal, of the dietary protein that is broken down to the amino acid sub-units, around 90% is absorbed by the gut. It is thought that 30–50% will be used by the intestine to maintain its own structure and integrity, and the remainder (40-60%) is released into the portal system (general circulation) to be used by the organs and muscles.
It is suggested that an excess of protein could potentially lead to a reduction in total gut absorption, consequently reducing the percentage of protein absorbed into the body…basically you’d excrete more when nature calls!
Gabriella, A, M., Have, T., Marielle, P, K, J., Engelen., Yvette, C. L., Nicolaas, E, P, D. (2007). Absorption Kinetics of Amino Acids, Peptides, and Intact Proteins. International Journal of Sport Nutrition and Exercise Metabolism.S23-S36.