The problem of a limiting amino acid is most simply overcome by

By combining vegetarian protein sources you can ensure that you are getting all 9 amino acids.

Explanation:

Giving up meat creates you to not get all your limited amino acids. This causes incomplete proteins and key amino acids from a diet. These amino limiting amino acids are: lysine, threonine, methionine, and tryptophan. Limiting amino acids are found in the shortest supply from incomplete proteins. Incomplete proteins are those found in plant food sources and geletin.