According to a new study published in the journal Evolution and Human Behavior, people who consume healthy foods like carrots and leafy greens are considered more attractive than people whose skin is darkened by a tan. Will carrots become the next beauty supplement? Here, a brief guide to the University of St. Andrews researchers' findings:

How did the experiment work?
Test subjects viewed images of 51 faces on computers screens, and were offered two ways to make the faces more attractive: 1) Imbue the faces' skin with melanin, the pigment-enhancing cell that's activated when people sun-tan; 2) Give the faces the gold-hued glow that typically results from eating carotenoids, the antioxidants in certain fruits and vegetables. The test subjects favored the second method, "improving" the faces by adding enough carotenoids to equal five servings of fruits or vegetables a day. Another experiment in South Africa, using black students and images of darker faces, produced a similar result.

Which foods best deliver this glow?
It's not just veggies — like carrots, broccoli, yellow peppers, beans and leafy dark greens — but also grapefruit, avocado, strawberries, blueberries, flaxseed, nuts and seeds that are high in carotenoids, a naturally occurring pigment. Carotene, produced in great quantity by carrots, is the most well known. No animal products contain carotenoids.

Is it possible to overdo it?
Absolutely. Eating too many carrots could lead to an overdose of Vitamin A, says Dr. Susan Stuart, a dermatologist quoted by Medill Reports, which in turn can trigger fatigue, irritability, and gingivitis. And it could produce a skin tone that is more jaundiced than healthy.

What's the right amount?
You'll likely notice a difference if you eat five daily servings of fruits or vegetables that contain the antioxidant over a period of six weeks. The fewer vegetables you're used to eating, the more noticeable the transformation will be.

Sources: Guardian, MSNBC, Medill Reports, Treehugger