Re: High calorie foods? (need to gain)
It's good that you found out about your vitamin D deficiency. I had the same deficiency and now I take the amount that is recommended for my age. I don't believe in taking an extra large dose as some people do.
I think it's likely that your doctor also checked your B vitamins. At least I hope he did. If you have a problem with absorption, you might not be getting enough B vitamins from food and that might cause a problem with appetite.
In Japan they eat a lot of rice. Do you do the same when you're in the U.S.?
I know that Okinawans eat a lot of whole grains but when it comes to rice, they eat white rice. I don't know why they do that but maybe it just agrees with them. In any event, rice with some olive oil dressing would add calories. You would have to see if it makes you feel bloated.