The body has a strong, innate protein hunger and salt appetite because essential amino acids and sodium chloride are critical for survival.

“and so um whereas sugar and fat can be interchanged with other macronutrients so um and then there's other things also that you absolutely need to ingest like sodium chloride right so sodium so uh uh there's very if you deprive an animal of of sodium they will develop this salt appetite that's incredible basically and that's completely innate um uh but that's I think salt appetite and and and protein appetite are the things that are probably the most strongly regulated at the level of the macro micronutrients”