Looking for the best high-protein diet that can help you lose weightA protein is nothing more than a long chain of amino acids. Protein is said to be "complete" when it contains all 9 of the essential amino acids, and "incomplete" when it lacks one or more essential amino acid. These amino acids are essential because our body cannot produce them and they have to be consumed through food. Animal-sourced protein is usually complete while plant-based protein is often incomplete. This does not make plant-based protein inferior - it only means you need to vary your protein sources in order to receive a healthy dose of all the essential amino acids.