Some of the ab weighted workout I like are the Decline Bench Sit Up next to Cable Machine and doing a st up or Holding weight plate and doing sit up on decline bench and kneeling/standing cable crunch.  As far as foods, I eat lean protein (chicken breast, ground turkey breast, tilapia) with greens/veggies and carbs (brown rice, sweet potatoes and quinoa).  I also have a link of my wods and foods I eat you can check out.  Hopefully that helps! :]

Me personally when I was starting to see progress for my abs, was when I changed my eating habits.  I would feel the muscles there but couldn’t see definition.  So I started to change my eating habits and ate clean foods over process foods.  I also kept doing ab workout days, especially weighted ab workouts if you wanted to have the muscles peek through.  And gradually my abs started to get defined.  I mean everyone is different you kinda have to feel your body out as you make progress then you know what works best for you to achieve defined abs.