That is a difficult question because it depends on so many things. As a general rule of thumb: at any one meal don't eat until you are very full, eat smaller meals at night with less complex carbs, don't eat fried/processed/suggary foods, increase the amount you excercize. Instead of doing say 40 mins cardio at one slower speed, do intervals, where for 2 mins you go slow, and two mins you go flat out. that works well. Make sure you add some strength training in there too. If you did that well, you should see improvement in at least 2 weeks.