antinutrient
noun
variants:
or anti-nutrient
Medical Definition of antinutrient
: a naturally-occurring substance (such as saponin or tannin) found in plant-derived foods that interferes with absorption or proper functioning of nutrients in the body
Oxalate is called an "anti-nutrient" because it binds with calcium and some other minerals so they cannot be absorbed.— Chris Rosenbloom, The Atlanta Journal-Constitution, 29 Sept. 2009
also
: a substance (such as refined sugar or alcohol) that has little nutritive value and that typically depletes the body of more nutrients than it provides when metabolized