When losing weight you can safely lose between 5 to 10 lbs of weight per month.
So in 1 year you can safely lose between 60 lbs to 120 lbs of weight per year however some people have lost 140 lbs to 150 lbs of weight in a year safely.
But trying to lose more weight than 10 lbs per month may not be healthy or safe for some people but if you stick to a good diet, exercise etc then you can safely lose at least 120 lbs of weight per year which is pretty good.
So in 2 years you could drop 240 lbs of weight if that's your goal as it's better to lose weight more slowly than it is to try and lose the weight in a shorter amount of time.
It's not worth the risk of harming your health trying to overdo it when losing weight.