What diet should i do 2 get faster n lose weight but still stay strong?

i play football n im in da weight room 4 days a week. I'm trying to play tight end n i need to lose weight n get faster but i need to keep my strength. Since this week is spring break im running around my block in the morning and doin an ab workout after i get back in. All i need to know is what should i eat and not eat. My mom mentioned the atkins diet but tht seems like it would keep me from getting all the stuff i need to build muscle.