How to GAIN weight?

I've been taking adderall for several months now, and my weight has dropped significantly. I'm 6'1". I was like 185-190 pounds when I began taking it, I believe, and I'm now at probably about 155 pounds. I have seen a decrease in the rate at which I'm losing weight, but I'm still losing it, and before long I'm going to be at unhealthy levels. At first, I had a lot of trouble getting myself to eat, because it kills my appetite. I've managed to deal with that pretty well, so now I eat probably as much as I did before I started taking adderall. However, it seems as though I lose weight regardless of how much I eat, even if slower. Naturally, I could just eat a tub of ice cream every day and gain weight, but I would prefer to gain weight in a way that isn't so unhealthy. Are there foods that will help me gain weight without clogging my arteries?

Personally, I think you are and will be fine. I am currently 5' 11" and weigh 105 lbs. My dad is 6' and weighs 120 so 6' 1" and 155 is perfectly fine. I think that, as said, you metabolism is being messed with. Mine, as you can tell, works overtime so, most likely, the best way for you to gain weight would be one of the only two ways I can do it; grow or work out. And believe me, if your metabolism is like mine, you can't gain weight through eating. It just doesn't work. You burn it off to fast.