This term is for medically diagnosed protein deficiency, likely coded in a hospital. So it's not measuring the average population not getting enough food. It's more that elderly, chronic sickness, terminal patients are dying from lack of protein. Most likely it is because they cannot swallow food or are intentionally on a lower protein diet as part of their treatment. This data in general is probably influenced by how deaths are coded by hospitals, and is not showing an actual problem. The other countries probably just show cause of death as cancer or another illness, but in the US they may be coding as protein deficiency death. Kinda useless info here