Dermatologist Jessica Wu, M.D., author of Feed Your Face, lists foods that are high in sugar as the worst for healthy hair and skin because of their effect on blood sugar.
"Eating sweets causes blood sugar to spike," she tells Huffington Post. "As the body pumps out insulin in response to the rise in blood sugar, it also raises levels of androgen, a male hormone that can make the hair follicle shrink in both women and men."
This spike in blood sugar can also contribute to inflammatory skin conditions like acne, according to dermatologist Dr. Linda Stein Gold.
They make the “the sugar in the blood [to go] up quickly, and that triggers a cascade of events that increases hormones and increases sebum, and all this together actually causes acne to flare up,” she says.
Experts recommend following a nutrient-rich diet that's filled with healthy vitamins and minerals to promote healthier hair and skin.
“Nutrient-rich whole foods like fruits and vegetables, whole grains, and healthy fats are good for your whole body, and that includes your skin,” Rajani Katta, MD, FAAD, a clinical professor of dermatology at McGovern Medical School at the University of Texas Health Science Center at Houston, says.