I'm on low carb diet for three weeks now & lost 9 pounds but my weight stuck and not lowered any more i 'm on prednisone from 3 years ago till now .

Take your time: 9 lbs in 3 wks is great. Didnt say how much u have to lose but slow & steady wins the race. Dont forget to combine diet w daily exercise 30-60 min total. Hopefully u are not overeating fatty foods bec total calories is the main driver. Rather than strict atkins, i advise restrict fatty meat & dairy fat (use 1% milk), restrict hi-cal sweets & starches, but keep low-cal vegetables & even some fruit.