Losing weight isn't the problem at all, the lifestyle is the problem so that is what needs to be fixed. However to fix your lifestyle it take a long term commitment. Committed changes take time so you can learn them, adapt to them and adapt them to you, and eventually love them.
The problem isn't the weight, its the habits that caused the weight. So even though scientifically one can lose 1-2 lbs per week, realistically that may not always be true, because it is the bad habits that need to change and new habits need to be formed.