Did you have these same specific tests before you lost weight? What I'm wondering was were they high then and you just didn't know. Maybe it's not linked to the loss of weight.
I tend to go by Mayo Clinic's website if it's something I just want the basics on - but keep in mind, if you Google anything, they list anything and everything that could be wrong with you. Best person to ask is your doctor for more info, or get a second opinion.
http://www.mayoclinic.org/symptoms/elevated-liver-enzymes...
ETA: read your updated info. Sorry that your PCP isn't being more help. I would be frustrated too.
You mentioned cholesterol levels. They didn't put you on medication for that did they? Because some cholesterol drugs will elevate those levels (reason why I attached that link - it's number one on the list).
Added: Reading through your added info - if it were me, I'd go back to my PCP and ask for more tests (I think even Celiac's disease can raise enzyme levels). If she says no they are not necessary - at least get her to explain her logic. If not happy, then say you'd like a second opinion or to see someone specialized for follow up. We've had to do that before. Hope you can get it sorted out :)