A flat stomach starts in the kitchen, but instead of counting calories or anything look at portion sizes. You won't really get the results you want without some diet and exercise. If you don't want to do cardio then Pilates would be a good alternative.
100% agree with STOP there is no way whatsoever to spot reduce when wanting to lose weight. There r no miracle pills patches belts anything! Its all about following a beneficial and sensible diet and getting plenty of activity i.e. Cardio and weight training. Good luck!