How to burn off inches and A diet plan?

Hi everyone,I am going to a theme park trip in exactly a week,do you guys having ideas on how i can lose some body inches so I can feel more comfortable on the rides.Apparently,the maxium inches is about 50-52 - I am smaller then that but that is an estimation (the maxiuman) so if you have an simple ideas please tell me! Also I am only 13 years old so nothing to extreme,and I repeat,i am way smaller than 50 but i still just want to feel comfortable anyway and Also a diet plan would be good to xxx