The most effective way to lose weight is interval training. This means to run for a good 1-2 minutes, then brisk walk for 1-2 minutes, back to a run, then back to a brisk walk.
The reason this is most effective is during your 'walk' period your heart is still beating, and you are still burning just as many calories as if you were still running.. However, you are allowing your muscles the opportunity to rest, the lactic acid to be removed, and for fresh oxygen to be pumped to them to allow you to sprint again.
The result is, you will be able to train much much longer allowing you to burn more calories.
Once you've mastered this you can move from it to hiit (high intensity interval training) at which point you would would a weighted belt, weighted vest, and your rest period would be shorter.