Hello,
I have been training for track for a while now soon to be an Olympian. I'm 13 years old.Yes, I know I'm starting early I have a record I have to break! And no time to waste. I train for 5 hours every day from 8am to 10am then I have a rest break for an hour and a half and I train from 11:30am to 1pm. It sounds like a lot but, once you get use to it a stretch a lot its not. But, what should I eat so, I gain muscle and start to have a mre complex body? I also want to have energy to carry me out through the rest of the day.

The best thing to do would be to calculate how many calories you are losing and then replace those calories in addition to the normal calories you should be consuming every day. Protein is very important if you're training this much as are fruits and vegetables which give you the vitamins you need to survive. During breaks isotonic drinks like Gatorade can help replace electrolytes, but they won't help at all if you don't have a well balanced diet!

This is just the opinion of a health professional and experienced marathoner, but it's not considered very healthy for a thirteen year old to train five hours a day, especially without some sort of professional coaching. I hope that you have some sort of help with this or at least are varying your training regiment to prevent injury which is very common in young athletes who focus too hard on one sport. Additionally, I'd suggest cross training and including low stress activities like biking and swimming to help build other muscles up and prevent you from getting hurt before you even really get started. Also, it would be best to work up to five hours per day and have some hard days and some easy days.
Your body is still growing and developing, and training the wrong way can cause life long problems.

Also this website might be useful: mapmyrun.com I use it to track the calories I've lost during training and to help make sure I'm eating enough calories to replace what I've lost.

Good luck and make sure to mention me when you win that gold medal!