Is animal protein a life-enhancing elixir? From a young age, we’re taught it fosters health, growth, vitality, virility, and sometimes even weight loss. The alternative to getting plenty of it, we’re told, could be protein deficiency. Never mind that the typical American has never had—nor ever will have—protein deficiency and has little idea what its symptoms might be. We’ve heard of it, we’re scared of it, and whatever the heck it is, we don’t want it.

Spurred by the most basic force of meatonomics—the drive to sell more meat and dairy—animal food producers use our protein fears to their advantage. For example, a beef trade group’s website suggests when deciding how much meat to eat, we go beyond the bare minimum needed to “prevent protein deficiency.”[1] Elsewhere on the site, we’re warned:

HEALTH ALERT: Sarcopenia.

Sarcopenia is a condition associated with a loss of muscle mass and strength in…