I've gradually become more allergic to all sorts of things in the latter third of my life. It's a real pain in the butt.
Specifically Celiac disease.
I had a bad back. Years of it. Finally, I was due for surgery and just waiting my turn. A nice lady told me about her brother who was an estate agent. His back pain was such a burden that he would have a rest on beds in unoccupied houses. Quite unrelated, he went for a biopsy for Celiac and it was positive. When he went on the diet his back pain disappeared. Since a lot of my back pain felt like a patch of illness rather than a sharp crick, I mentioned it to my surgeon. He swung my MRI towards me and pointed at the close proximity of the down pipe and my spine. "If this is inflamed, of course this will hurt."
I took the surgery but also stopped cheating on the diet. "Oh, a little of that won't hurt, etc., etc." Stopped dead. My life was transformed, and I'm sure it was a mixture of both remedies.
I wonder if the biopsy is still needed for confirmation. It's not pleasant, but I refused drugs. When my result came back negative, the charming young surgeon said, 'but it doesn't mean you're not allergic to gluten'.
Many of the dietary things are helpful in maintaining weight. All in all, it just stops me being tempted. For a brief period my local (Celiac) baker made wonderful brown bread using Teff grass. To have toast and marmalade in the mornings was such a treat.
I can't drink beer, or Scotch. It makes me ache. One of my sons is the same.
I drown potatos in cooking oil having microwaved them. Nicely sautéed makes a tempting improvement. Darn. Never gave it a thought. However, since I've been doing that I've been holding 14 stone which I thought I'd never go back to. Motivated now to a smidgen of best Olly oil and looking to see what else I'm cheating on.
Since getting old I don't feel too good with a lot of things, but well into my 70's I was very fit and studying late into every night on physics forums etc. I felt confident that should the crew of my aircraft be abducted by aliens, I would manage the flight with ease. Assuming I could get in the flightdeck. Over eighty, not so sure, but I don't suppose you're planning on a career of that length.
I flew with a guy that had allergy to peanuts on his licence - not sure how it was worded, but his reaction was dire. I doubt being Celiac would be remotely comparable.