What should not be consumed to prevent discomfort when flying at high altitudes?

To prevent discomfort when flying at high altitudes, it is advisable to avoid carbonated beverages. The reason for this is that at high altitudes, the lower atmospheric pressure can cause gases in the body and in food to expand. When consuming carbonated drinks, the release of gas can lead to increased bloating and discomfort, making symptoms of altitude sickness more pronounced.

On the other hand, complex carbohydrates, protein-rich foods, and high-fiber foods are generally considered more favorable choices before a flight. Complex carbohydrates and protein can provide a steady source of energy while high-fiber foods can aid in digestion, which is beneficial for overall comfort during the flight.