Please, need help on eating schedule, training for fullback/linebacker.?

So first things first I weigh 187 and I'm 5'8. I have a gut a good natural build and im going to be in 10th grade. I'm just trying to lose some of this gut without WITHOUT WITHOUT LOSING MUSCLE! Seriously that's a big thing and I also don't want to get weaker in weightroom while losing this weight. I wake up in the morning weight lift at school, do speed camp after that, then go to the local gym for cardio. I have all the workouts down, but I need to know a good diet plan, I've been training to the extreme for about three weeks, but i've only lost five pounds. Most bodybuilders say 90% of body success is food, healthy food. I need to know hours when I should eat and how much please please help, thank you so much!