You can lose weight fast by engaging in fitness exercises that help you burn calories in the body. Some of these exercises include cardiovascular exercises like running, jogging, skipping and swimming. You can also do other exercises like aerobics where you do a lot of stretching and strength training exercises that burn off the calories. You can also go on diets like the water diet, the juice detox diet, the master cleanse, the cabbage soup diet and the salt-free diet. Read more about these diets on http://www.wikihow.com/Lose-Weight-Fast.