From a guy who lost over a hundred pounds and have kept it off for a long time this is how you do it:
Stop eating McDonalds, Burger King, etc. Avoid grains. Avoid carbs. If you can keep your carbs under 30 or so a day you will have more energy and feel much better than you today. Consume high protein foods like meat (not fast food), fat free milk, eggs, cheese, peanuts, etc.
Do some type of aerobic activity. Anything repetitive that gets your heart rate going. I walk as fast as I can for around thirty minutes every other day. The time spent doing that is about how long it takes to watch a sit-com on TV.
If you smoke, quit.
The reason you are carrying a fat gut is from the choices you make. Change those choices with healthy things you can live with and your fat will burn off your body in the form of energy.