Since taking up Pilates, I've seen an enormous difference in my core muscles, and, combined with my 80/20 approach to a balanced diet, have been noticing better definition in my midsection, too.
My stomach has always been a problem area for me, and I maintain that your diet will move the needle most when it comes to how much muscle definition you show there, as well as other (quite annoying) factors like health conditions, sleep, stress, muscle-building workouts and genetics.
