Hello and welcome! I wouldn't recommend a 4 to 5lb weight loss to keep up with. I know for me, I'm gonna try for 20lbs in one month, then knock it down to about 2lbs per week. It also depends on how much you have to lose, whether it comes off quicker or slower. Make sure to keep up with eating right and exercising and if you find that you are having problems with losing weight that fast, then aim for 2 to 3lbs per week.
That's the best I can help with! (Though, I could be wrong myself, but others around here are rather helpful)