Yuri SNSD's diet plan i read in articles that yuri eats about 1,200 calories a day. she eats about 4-5 meals a day but she eats healthy in her meals. Snsd mostly eats fruits and veggies and they mostly just drink water and milk. Yuri is actually an average weight but slimmer U can go on a water diet. Like when ur hungry instead of eating some junk food or whatever u eat, drink a tall glass of water. Water fills up ur stomach and makes u have clear healthy skin =]

*Yuri enjoys bananas, bell tomatoes, cabbage, chicken , milk, and sweet potatoes (i got this

from this website* 

Meal Plan
breakfast- you can drink a glass of milk and have a banana or some other fruit.
i suggest not to skip any meals because it will just make u eat more in the other meals. if u dont have time to eat breakfast u can try taking the banana with u and eating it on the way. i skip breakfast so it makes me hungry by lunch time.
lunch- At lunch u can try having a bottle of water and some veggies. 
Snack- ur should be healthy and not be junk food.
Dinner- Try telling ur parents u want something else like a cup of rice and some veggies.

You also shouldnt skip meals. It just causes a chance to gain weight. However u can try to skip a meal once a month but thats it.

Snsd Yuri have school and pratice and all that.
I suggest u should learn the dance to Gee ( dance version) 
link-http://www.youtube.com/watch?v=ScIpxucdm…
learning it- http://www.youtube.com/watch?v=AnR5RO6tC…
http://www.youtube.com/watch?v=e4RML9Twj… - part 2
they exercise A LOT. 
so maybe u can exercise 30-50 minutes a day. 
and if ur in school and its not that far away try walking to school. 
oh yea n i know ur aiming to be yuri’s size but tiffany and jessica shows how they stay skinny. 
http://www.youtube.com/watch?v=DHexO1dBH…
* Yuri also tries to do Jessica’s exercise*