The health of your hair is affected by many factors, including genetics, the environment, and medical conditions. However, it is nutrition that plays the largest role in how well your hair grows. Like every other system in your body, hair needs certain nutrients in adequate amounts for proper growth. There's no doubt that what you eat matters, but there's one burning question. Can eating fast food cause hair loss? This is your guide to fast food's role in hair loss and the nutrients needed to support healthy hair growth.