As you may recall from The Magic School Bus, a considerable intake of carrots can actually make your skin orange. But, diets high in pigmented antioxidants (like carotenoids) will give skin a yellowish hue, where diets devoid of vegetables will leave skin a purple color. The former suggests a healthier lifestyle, while the latter is linked to a greater risk of both infection and mortality. While previous experiments have shown the yellow-faced preference, it's unclear if this is because of its suggested health marker or an aesthetic choice.
To clarify our chromatic bias, a British research team conducted a study in which 56 participants viewed a collection of photos of Caucasian faces. Half the photos were adjusted to reflect the yellow or purple hues, while the other half were a scramble of those faces in their respective color tones. Participants rated the yellow-toned faces as more attractive than those with the purple (read: unhealthy) faces. But, those who saw a scrambled image had no preference between the two palettes. As a result, the research team claims that yellow skin is more attractive "not because of a sensory bias toward yellow colours," writes the scientists in the science journal Biology Letters, but because of its service as a health marker.
Obviously, there's a glaring gap in this research, as only images of white people were shown. Much more research is necessary to solidify the claim, which as it stands is exclusive to all other skin tones. However, it's interesting to see the ways our bodies can betray us by suggesting the nature of our dieting, or lack thereof. (Discover Magazine)