To be honest, this is a question people are always asking, but don't really want the answer for. First...what's your time frame? Are we talking about having fabulous abs by Friday, or by July? It makes a huge difference to the approach you'll want to take.

If you want fabulous, flat abs by Friday, and you don't want to change your diet, there are a couple things that might help:

1) Stand up straight! Posture makes a huge difference in how slim and fit you look.

2) Drink lots and lots of water. If you're bloated or retaining water because you eat a high-sodium diet, drinking extra water will help get rid of bloat, creating a sleeker looking physique.

3) Make sure to get your cardio in for the week! All the calories you can burn before the weekend are going to help.

4) Eat protein following your workout. This will help build muscle, which will burn more calories at rest.

If you have additional time to achieve your desired state of toning (like a month or two), follow the tips above, but also add in some form of weight-bearing exercise. You don't have to become a body builder, just add lunges, squats, push-ups, etc. to your workout. By increasing muscle you'll contour your body & lean up, giving your tummy that toned look you've always wanted.

Now...you don't want to diet. That's fine. What I would suggest, however, is to make little changes in your food consumption. Little changes can make a big difference. Instead of drinking wine every night, drink it every other night. instead of putting mayonnaise on your sandwich, use mustard. Also, if you're a coffee drinker like me, make sure you aren't sabbotaging your efforts by adding whipped cream or whole milk to you latte.

Best of luck getting rock hard abs!