I am a track and cross country runner so I do know what I am talking about. All that stuff about cutting out the meat and everything is not the right thing to do (no offense). They key is to train every day of the week mabye allowing for a day off here and there for rest. Since you are diving you don't need the speed training, what you NEED is to run for milage. Go out every day and run continuously starting at 30 mins for a week and incresing it by 10 minutes every week. You should also be taking Vitamin and caulcium supplements to avoid hip, ankle, and shin problems. Keep in mind with training that two days of inactivity will severly effect you when you go back to it. Don't only run though since diving is all swimming got to th pool and swim laps for at least one or two of those days of the week. This works muscles that arent exercised with running. If you are wieght lifting to bulk up you should consider stepping beck a little you want functional mass. Do situps every day. When you are out of energy the strength to keep going comes from your core.
As far as diet goes you shouldn't be limiting your calories that much it can be detrimental. During training you shouldnt be counting calories that much (I eat 2500-3000 at least). Cut all the sweets and greasy foods from your diet. Alcohol won't do you any good either!!!! After you work out you should be getting a healthy amount of protein. Try to limit the fats and carbs somewhat but DON'T cut them out your body needs these when you are training. You cant starve yourself when your follow a good training schedule, you will get to the point that you will injure yourself, then your screwed. With this method I kept my weight steady at 163, dropped almost 10% body fat, and built lots of funtional muscle mass, all in 3 months or so. This is not totally my idea, this was taught to my team by two coaches. One that was a national class runner and the other has been coaching a champion team for over a decade!
Good luck with the training. Keep in mind that if anything starts to hurt don' tjust block the pain with meds, use ice and some rest. Oh, and if you take calcium supplements your body can only process about 700 milligrams a day so don't crazy.
Bottom line don't listen to the people that say cut the calories. The average body uses 1000 to 1500 a day just to perform life-sustaining functions and average day to day activities (not including work or exercise). If you have any questions send a PM. Good Luck!