My 14yr old daughter has changed a lot in the past year.. She went for 8 and a half stone a size 10 to 7 stone a size 6/8 and kids clothes. I am very worried about her as she has lost a stone and a half in 12 months and now exercises 4 days a week which may not sound to much but she is so thin and has a body fat percentage of 10 percent which just seems not enough. She is very sporty but I fear that she is slipping into some sort of eating disorder or mental illness. She avoids inviting friends around for tea as she knows I'll make them eat pizza and popcorn ect. She gets very upset when she is made to eat a slice of cake or a packet of crisps which obviously isn't often but she gets very upset. Should I be seeking help or stopping her from exercising??