Weight Loss Plateuas, Why Do I Get Stuck on a Number

So, short background: down 17 from the all time high, but now stock on a number. Been within 1 pound either side 230 for about a week or longer ... despite still doing pretty well on exercise, diet and counting calories. 55 years old, male. Do others of you get stuck or plateau for a while? Does anyone know why it happens? Any tips to break through. It was coming off at a much better clip than I seem to be on now. I am weight training as well, mostly light weight, more reps to tone and have convinced (lied to?) myself that the weight that is staying on is better. Feedback appreciated, thanks.