It's not just the boiling point. Food tastes less salty as well.

I once cooked a stew for friends at 8000 ft. I thought I had made a mistake because it tasted so bland. After the trip I had the leftovers at sea level and realized it tasted just fine. It gave me an appreciation for the fragile relationship between location and following recipes. (Humidity also changes taste)

Probably why airplane food is made extra salty to compensate for the rise in altitude