Some Americans distorted insights from nutrition science to spread pseudo-scientific arguments about white racial superiority. Proponents of “racial science” claimed that the endemic poverty of immigrant neighborhoods was a byproduct of biological differences and inherited racial traits. Racist arguments about the “fitness” of poor immigrant mothers cited new national height and weight standards, originally developed to measure malnutrition in children. The most extreme positions blended theories of biological racial hierarchy with Charles Darwin’s concept of natural selection to justify policies that would ensure racial purity, such as segregation, sterilizations, and immigration restrictions.