Previous studies have shown that flying at high altitude can cause serious health problems for many people.
It causes oxygen levels in the blood to fall and can lead to fainting and even heart attacks among some passengers.
But research carried out in Japan suggests that eating prior to take-off can help the body's blood to circulate more easily and reduce the risks of falling seriously ill.
Low cabin pressure at high altitude causes blood vessels to expand in an attempt to increase oxygen supply.
However, the amount of blood pumped by the heart remains the same causing a relative reduction in oxygen supply.
While just one passenger out of 800 flights suffer major health problems while flying, recent reports of deaths have raised concerns about the risks of flying.
The Japanese doctors used a simulator to study the effects of flying on 12 volunteers at 10,000 feet.
They measured heart function, blood blow and the supply of oxygen to the brain and other organs in a simulated aeroplane environment after the volunteers had fasted for 12 hours.
The doctors found that, after fasting, heart function and blood flow volume remained the same in the volunteers.
However, the effects of reduced cabin pressure caused blood pressure to fall and the level of oxygen in the organs and the brain to drop significantly.
The tests were repeated after the volunteers had eaten and drank.
This time the doctors found that there was no change in blood pressure compared with normal levels outside of the simulator.
Instead, they discovered that eating and drinking increased cardiac output and blood flow to the brain.
Their study also revealed that eating and drinking before a flight increased oxygen in the organs by 21% and in the brain by 48%.
Protect passengers
They believe that these increases could protect many airline passengers from falling ill during a flight.
Dr Makoto Matsumura from Saitama University in Japan who carried out the study said it was important airline passengers ate and drank before flying.
"Having something to eat and drink is the simplest method of increasing the circulating blood volume for air travellers.
"Most are probably doing it before boarding anyway, but people need to know it is easy for their bodies' oxygen levels to drop if they don't eat or drink before boarding."
He added: "Medical personnel and travellers should know that hunger can cause in-flight emergencies and fluid is probably even more effective in preventing emergencies.
"Older individuals and those with high blood pressure or vascular disorders are especially at risk for these types of emergencies."
However, speaking at an American Heart Association's conference in New Orleans in the US he warned that airline passengers with a heart condition should not eat or drink too much before travelling.
"If a large amount of food and fluid increases the circulating volume too much, it may induce heart failure in people who have heart disease."
The Japanese research team is planning to carry out further research to determine how much airline passengers should eat and drink before flying.