What should crew members participating in unpressurized high-altitude flights avoid to reduce the risk of trapped GI gas?

To reduce the risk of trapped gastrointestinal (GI) gas during unpressurized high-altitude flights, crew members should avoid foods that are known to cause discomfort or increased gas production in their digestive system. Foods like onions and cabbage are known to contain certain compounds and sugars that can lead to bloating and gas formation in many individuals. When flying at high altitudes, the decrease in atmospheric pressure can exacerbate the discomfort caused by trapped gas, making it particularly important to manage dietary choices effectively.

In contrast, high-fiber foods, caffeinated beverages, and fatty foods can have varying effects, but they are not as directly linked to the specific issue of trapped gas in the same way that foods known to cause discomfort can be. High-fiber foods, for example, contribute to overall digestive health but can also lead to bloating in some people if consumed in large quantities. Caffeine may have a diuretic effect and could not directly relate to gas accumulation, while fatty foods can affect digestion differently, often slowing it down but not necessarily creating gas.

Thus, being prudent about avoiding foods that are personally known to cause gastrointestinal issues, such as onions and cabbage, is the best strategy for preventing discomfort due to trapped gas during high-altitude flights.