Lots of great advice to you has already been given. But one thing to add - the walking may be good for your heart, but it's burning calories. You need an ener

Lots of great advice to you has already been given. But one thing to add - the walking may be good for your heart, but it's burning calories. You need an energy surplus (more calories coming in than going out). If you are walking a substantial distance to work, more calories are going out. Again, I'm not here to discourage cardio activity completely, but that's not the exercise you need to focus on. Saucisse is right - you need to eat more and more frequently. And to ensure that doesn't all become fat, you need to lift heavy - focus on compound exercises like squats, deadlifts, bench press. Stronglifts is a great place to start. Good luck!