Kim who was here for awhile, started having her hair fall out by the handfulls when she was on Atkins the first time. She was getting really worried by it as I recall. She was on induction for most of her losing time and was losing weight really rapidly, I think it was about 6 months into it that she started losing her hair. It happens.
I lost hair a few times in my life, like that. Once when I was very young and once later on. I fasted fairly often when I was young, I'm not sure if that was the reason for it. Usually no more than 3 days at a time, but I can't say that I knew the reason for hair loss then. The other time I can't say why it happened, but I don't think it was weight loss that caused it.
Rapid weight loss WILL cause hair loss though sometimes and in some people.
Regarding hair growth. I've always had a lot of hair and it has always grown really fast. I measured it once, and noticed that it grows about an inch a month through the summer months. Slows down sometimes during the winter so that my hair growth for the year was about 9 inches.