It is possible to loose 80 pounds within about 4 to 5 months. However, it is not wise to do so as your body needs to slowly yet consistently adapt to new regimen. You should schedule a gym program and change your diet. Give yourself more time for you to have a healthy body.
It depends on how much you way to start out with. If you weigh 100 lbs than you would only be 20lbs and die. But if you wiegh 260 lbs losing that amount is possible, but you should do it over a longer time period because it would be much healthier and safer. -S-
This depends on how much weight you need to lose. The average, healthy rate of weight-loss is no more than 5 pounds a week. At 4 weeks in a month, it is possible to lose 80 pounds in 4 months since you can possibly lose 20 pounds in a month. Now, that's if you are really overweight - like, you weight 250 or more. Someone who is maybe only 50 pounds overweight shouldn't be losing 5 pounds in a week, that's too extreme.