My daughter needs a quick and effective diet plan?

My daughter is 12 years old and weighs 120 pounds and she is 5'5". She is slightly over a healthy weight and is looking to lose some belly fat. She has a bike and enjoys riding it and she runs like 5 miles on Wii Fit every day. She eats very healthy and she's a vegetarian. Her belly pops out a little and she doesn't like that. She wants a flat belly. Any good diet plans, like foods and exercises?