'Protein' is one of the most important nutrients that human body needs on daily basis. It is made up of essential and non-essential amino acids--the BUILDING BLOCKS for healthy body.
Protein (1) builds and repairs muscles and bones, (2) repairs cells in the body, (3) provides energy, (4) controls many important metabolism-related processes in the body.
Also, individuals who are into regular gymming/exercises, and athletes require more protein in their diet (twice the recommended daily protein intake).
Actually, protein is the strength of a human body; we all should take recommended amount of protein daily in order to keep our body fuelled all-day long.
As far as digestion is concerned, protein comes in many forms; here, we are focusing on the simpler forms of proteins that are easily digestible (even without exercises).
The following products (scroll down) are proteins that get digested easily, without causing any health issues.