How can i lose belly fat, & gain muscle at the same time?

Eat less, exercise: You should try for 45 minutes a day of some type of aerobic (moving a lot) exercise. For diet, you should try to eat less overall, and pick healthy foods that are found in nature (fruit, veggies, grains, fish etc) . Sadly, oreos are not included. If you add in some resistance or weights, that will also add muscles. Walking uphill can do this easily. There is no magic, quick fix. One pound/week.