Happy New Year Denise,
I think you might be the pioneer in determining if you can lose weight while still on prednisone. I was on it for two separate weeks, for a bad case of hives, and still eating sugar. I gained 6 kilos in a month, but I thought it was the sugar. Now I realise it was the medication.
It may not make you feel better while you're unhappy with your weight, but being off sugar will save you from cancer, heart disease, diabetes, kidney disease, skin cancer, tiredness, bad skin, etc. I am beginning to think these risks are so much worse than being overweight anyway.
You can focus instead on eating healthily and drinking lots of water. I've read about people overcoming cancer when they fix up their diet and liquid intake, and so maybe your condition will improve so you can go off/ lessen the prednisone in the future. I hope so, but you should feel better overall, anyway.
-Dennise F