Running will only strip your body of muscle, causing to to add more fat so you stay near your set-point. If you want your belly to disappear, you need to grow muscle, not destroy it. Stop running (for the most part - I'm sure indulging twice a week won't do too much harm at all, and it's probably fun for you!), start doing plenty of bodyweight exercises and then lifting the heaviest weights you can 5x5. Simple as that. Eating lots of protein is obviously mandatory, but not as much protein as you might think. As your body lays down muscle, your fat likely will disappear. Simple as that.