Lactose intolerance is one example of what I call nutritional imperialism: a way of thinking that treats white diets as the norm and everyone else’s as an aberration.

Nutritional imperialism was common in the 20th century, when scientists thought that not only milk-rich but also meat-heavy diets were best; they considered diets outside of the United States and Europe too vegetarian. Some also argued that wheat flour, not rice, ought to be the universal staple.

The same bias applied to bodies. Besides faulty lactose digestion, nonwhite bodies were accused of other failures, too, such as aldehyde dehydrogenase deficiency, an inability to digest alcohol quickly. The less technical term for this may be more familiar: Asian flush.

Such differences might have been thought of as variety, just another way of being human. Instead, each became a deficiency.