@CO3 Few things off the top of my head:

• Mouth breathing/sleeping with open mouth, or having a dry mouth in general.
• Bacterial translocation from small intestine.
• Food allergens as you noted.
• C and B vitamin deficiencies, should not really be an issue for someone peating but worth considering.
• Hormonal changes, gum inflammation is connected to increases in estrogen.
• If accompanied by gum recession, something driving jaw bone loss such as high PTH, SSRIs, not enough calcium/vitamin D&K/magnesium, etc.

If the inflammation is unaffected by antibiotics then I'd probably look elsewhere than antibacterial measures for a solution.

@atlantean1488 Ballooning in weight is not a given just from peating, and having sustained a severe eating disorder will buffer weight regain in the beginning simply because of the sheer amount of calories required to restore lost organ mass.
Starting with a carrot salad won't be very productive. The carrot salad is a tool for a specific issue. Your girlfriends issue right now is a lack of nutrition, something which a carrot salad is ill fitted to amend.
The most fundamental aspects you should focus on is making sure she gets enough protein through ruminant meat and dairy, as well as trying to get her to consume adequate carbohydrates to begin restoring her body. Increasing gradually to allow her body to adapt to the new energy availability.
(I would focus on fruit juices, easy to digest fruits, possibly white rice, chocolate as a snack if you can get her to eat it.)
If her iron status is really poor there's merit to supplementing a well tolerated iron supplement (iron protein complex perhaps) for a short time even though it's typically looked at with caution through a Peat prism.
Do note that a clinical eating disorder is no joke and getting her to actually comply will likely be extremely difficult depending on how serious her situation is.

Best of luck.

what was the motivation for the carrot juice lmao?

@metabolicmilk Qingdao Sigma Chemical sell raws for hormones and DNP among many other substances. Thats a well known vendor often featured on MexoRx forums (good place to look for sources overall).
Ships from China so customs may be an issue depending on where you live. They might offer a repackaging solution for shipping too, many vendors do, but I haven't checked personally.

PPL has been in question as a source for a while now with a lot of reports saying their product are no longer up to standard. I believe they had a change of ownership too.