I get a little sick about 9500’ and up for the first couple of days, every time. It’s been that way for 20 years and pretty independent of fitness level or work load. Nothing terrible, just mild headache and loss of some appetite. If I’m up and back down bagging a peak or something it’s almost unnoticeable.
I’m not a super skinny guy, I don’t sweat a calorie deficit for several days as long as I’m getting electrolytes. I’ve found some personal snacks that always sound good just through trial and error. Coconut stuff, trail mix, Oreos, summer sausage, apricots, powdered Gatorade or similar, a few other go-to’s.
Really no way to know but try IME. My best advice is don’t put yourself in a box with food options, whatever sounds good, it doesn’t need to be fancy.