How can I get a flat stomach fast?

I am 21 5'9 and about 120 so you can see Im kinda tall and skinny but I have this pooch that runs in the family. My stomach expands tremendously after a meal. I want to tighten my lower stomach. Im tired of being a twig with a gut! lol I have found that not eating will make my stomach flat but thats not healthy! I just want to know if theres a diet plan I need to follow along with exercise a particular plan for my lower stomach. Someone please HELP! lol Thanx