Too close for comfort, cheek by jowl, packed together like sardines. All of these phrases accurately describe the seating in the coach section of just about every commercial airline.

That's why one of the last things that you, or the people seated closely around you, want to contend with while on board is flatulence.

The average person (male or female, old or young) passes gas about 14 times a day when at ground level. But after liftoff, as you gain altitude, the gasses inside you expand by about 30% — even in a pressurized cabin.

The result is high-altitude flatus expulsion, or HAFE.

Airline cabins are pressurized to around 6,000 to 8,000 feet. Think of the cities of Boulder or Aspen.

In fact, Colorado researchers published a study in the Western Journal of Medicine that found HAFE also occurs to people on mountain hikes.

The good news is that whether you're crossing a mountain pass or reading a copy of Inflight magazine, the right diet and over-the-counter anti-gas medicines can quell your tumultuous tummy.

Before you fly, skip beans, broccoli, cabbage, and other foods that you know will give you gas, such as dairy or spicy foods. Drink plenty of water, and stick with proteins and good fats found in tuna, salmon, nuts, and avocados.

If you do get gas, it's not smart to hold back. That can result in painful intestinal cramps, elevated blood pressure, and reduced blood oxygenation, all of which are bad for your cardiovascular system.