http://www.livestrong.com/article/331651-burning-fat-vs-glycogen/
Keep scrolling till you can't. These articles might help you understand (if you don't already) a little about the process and what's taking place in the body.
My best beginners advice; don't concentrate on carbs/protein/fats so much and just stick with a simple 40/40/20 split and eat under what you burn in a day by 500-1000 calories. Stay away from sugar/salt as much as possible. Eat whole grains/vegatbles/fruit and lean (unbreaded) meats. Don't skip breakfast and eat light at night. Hit the gym and give it all you've got when you are there, don't skip rest days and get good sleep. It's not a day, a week, or a month.. it's your life; but take it one day at a time. Good luck everyone.
Edit: AND count your calories. Biggest mistake is guessing. It's tedious at first but you'll get fast and it'll just be routine. As you lose weight, reduce your intake. (If you hit a plateau. But don't slash 500, cut out an extra 200 one week and see how it goes and reduce if necessary) remember your goal is sustainable change. This isn't a get rich quick scheme, it's a Tortuous and The Hare model.