Gaining weight

For me, gaining weight has always been more successful when paired with consistent but not too difficult exercise.  Also, removing a stressor from my life has been a great way to gain weight and for general health: the most recent time I had to remove myself from the toxic culture of a particular yoga studio.  (Isn't that funny?)  I'm not sure about what to tell you to eat.  Sounds like you have tried everything.  There is a good book called "Healing with Whole Foods" that addresses certain conditions and is a good guide.  When we have missing parts of our guts, we don't absorb as much nutrition, so if our food is easy to digest, they theorize that we can get more from it.  They suggest combining the food in advance, which would mean smoothies and crock pots.  Cooked veggies and fruit are easier to digest.  So are finely ground things because they're pre-chewed.  So blended soups might help.  Also there are great suggestions for managing gut conditions in the book "Listen to Your Gut". 

https://www.amazon.com/Healing...rition/dp/1556434308

https://listentoyourgut.com/

I always have problems gaining weight. For me the best option is doing as little as physically possible and eating as much as possible. It also depends on what you can tolerate for diet. Please provide more information on your diet, daily routine and any other issues that could be at play.

If I am sedentary I usually end up feeling terrible.  I guess it's a body type thing.