If you run 3000 meters continuously, you will consume about 750 kilocalories. Generally speaking, jogging helps to lose weight (I think 3000m should be jogging). Should be able to slim down, of course, depends on the diet. If you eat too much, or eat too many high-calorie things, you may still be unable to lose weight. I suggest that you eat more vegetables, less greasy things and less sugary things when running. I wish you success in losing weight!