Originally Posted by Unregistered:
First of all. A big hug for you 
. You are not a failiure as a parent. You are learning and parenting is always a learning journey . You have been doing your part with limiting junk food, which is good I can give you a couple ideas you can use, or you can change them to fit your needs :
1. If there is a sport they like, get them a ball to play with. My sister and I enjoyed playing catch outside with a baseball. We threw it gently underhand. I also have a football in my room that I would throw inside the trampoline in my yard (My sister and I outgrew the trampoline)
2. You can buy a trampoline and turn trampoline jumping into a competition. For example, whoever jumps thirty times first gets to watch one episode of their favorite show on TV (only an example reward you can pick)
3. If there is a swimming pool center where you live, you could get the girls new swimsuits, amd all of you can go there for a swim this costs money due to the season passes or admission price.
4. Since they are all involved in dance, have them come up with their own dance routine it can be however they want it, and they can choose the music (Clean lyrics of course )
The last thing I want to mention is have them get their labs run by their doctor. In particular, have them check their thyroid levels. If it is low, they will be able to take medication for it (I say this from personal experience because I have it. ) It is called hypothyroidism.
Big hug and lots of good luck to you and your family
This is great advice!!
OP~ the only thing I want to mention is don't equate thin with healthy.
Healthy is healthy at whatever weight is right for you (general you).