Underweight

Only a DEXA scan will give you information on bone liss. Blood tests are guesses, and not very good guesses.

nuts and seeds have a lot of enzymes - making them simply indigestible.  specially raw nuts. 

At one time I was eating a lot of nuts because dense proteins gave me troubles...  I was eating close to 200 cal (based on MFP ) and losing weight. Plus with RNY - I do think I can'd digest nuts very well - unless as nut butter.  I know that even if I try to chew them really well - most go through me undigested. 

I started sprouting the nuts and seeds and my weight loss stopped. It does not work that for everyone - but it sure worked that for me.  

You may need to add fruits and starchy veggies.. and take digestive enzymes. 

That is interesting. By a lot, I mean a handful a few times a week. Not daily. And I eat peanut butter several times a week. Not just for protein but I need the calories and good fats! It's funny how a lot used to mean one thing, and now it's totally different. ? I do take probiotics daily. And I'm vegetarian, so 90% of my diet is fruits and vegetables. I don't do any bread, rolls, bagels, etc because of my Sjogrens (I can't swallow them due to dryness), and I can't do pasta or rice often either for the same reason. 

Unless you have parasites, or your doc gave you ERNY - you may not be eating enough. 

I know 8 years post op - I deal with IBS and some days I rather not eat if I had to eat proteins...but I know I have to. 

Increase calories.  Eat more proteins... And good fat. If I had a low calorie day - I eat nuts. Soaked - sprouted nuts.

I hope you find what is wrong. 

Have you considered celiac disease?  It is an autoimmune disease too.  You don't eat bread but you do eat cookies and they contain gluten.  Just a thought.  

Yes. I don't have symptoms really, but I have been tested for that and it was ok.