I started drinking coffee in highschool - 1998. I noticed my blond hair getting much darker and coarser a few years ago, 2015 or so. I realized I was getting high blood pressure from the coffee and quit coffee (they say caffeine causes your body to retain salt and excrete potassium to protect your heart from dehydration). I noticed my hair is getting lighter and finer again - 2016. When I was drinking coffee, my hair was actually getting about six inches of black on the root end, and then the hair would just fall out, as well as darkening somewhat overall. My diet has included more raw eggs, green veggies, and fruit, too.