My husband started using Advair 8 months ago for mild asthma symp...

My husband started using Advair 8 months ago for mild asthma symptoms. He was taking the largest dose for the first month, and has been tapered down to the smallest dose twice a day now. It has really helped him breathe easier, but he has gained 40 lbs since he started, and is continuing to gain about 4-5 lbs each month. He has been trying to watch what he eats, but he just keeps gaining weight. I've talked to his doctors about it, they say that there is not enough steroid in Advair to be causing this, but I find this hard to believe. He has never had a problem with his weight before.