While it is not easy or inexpensive to store meat, plant protein can be stored very economically for a long time. Children need as much as adults because they are growing. A rapidly growing child can require 2 to 3 times more protein than an adult by weight. A safety factor was built into the RDA for protein and actually represents a little over twice as much as our bodies actually need. This amounts to 100-300 grams.
Protein is required for growing, body repair, and maintenance.
A person with serious physical injuries or illness requires much more protein. If we do not get enough protein, our bodies will steal it from our muscles. This is also true when we are ill. We need more protein, but often can't eat it. North Americans generally eat 3 to 5 times more protein than they need.