Are you a man or a woman? Running can only make your legs stronger and thinner, but you will lose a lot of weight. Last year, my average speed was 12, and I ran for 50 minutes, 10 km. I weigh more than 30 kilograms in 3 months. If you are a girl, it is recommended to slow down to 10 speed and run 1 hour. The slimming effect will be obvious. If you simply want to thin your waist and legs, it is recommended to breaststroke 1500m-2000m every day for 45 minutes-1 hour.