If you want to lose 20 pounds in 20 days, you need to start doing exercise and a proper diet. Start running in the morning or every other day. Start reducing the food you eat and workout every day as far as you can. This will help you to lose 20 pounds. I know you can do it, good luck.
You really can't lose twenty pounds in twenty days unless you sever a large limb. Try to do it in a healthy way; a pound a week is considered healthy. Eat fresh foods, drink a lot of water and start running- mix some weight training in there too
I don't know if it's possible in 20 days but just change your diet and exercise a lot more. A little bit after you eat each meal to burn off more calories. Take a jog around the neighborhood, bike, hit the gym. Your gonna have to do it regularly though since you wanna lose in 20 days (jeez! why the rush?). And eat healthier. To lose weight, you don't necessarily have to push yourself away from more food, you can eat the same amount you do normally but you need to make healthier choices. Don't avoid eating food, you need those calories as part of your daily caloric intake!!