The skin dicoloration comes from insulin problems. I also have that and was told by my doctor that it's a sign of insulin problems.

It's hard when this isn't your daughter and her parents aren't open to helping their child or open to suggestions from others. Some people resent others help because they'd like to think they know it all!!! Unfortunately they only end up hurting someone they could have helped!

If I were you, I'd invite her over for the weekend, and serve her nothing but low carb all weekend. On Sunday I'd ask her how she's feeling! Explain to her what you're doing with your daughter, and say that the meals are to support your daughter. Maybe she'll catch on, and want to be like her (sometimes they like to do that)

Good Luck!