Also, airline food is prepared, chilled and stored until it is loaded onto the flight, which could be a few hours from when it was cooked. According to Harold McGee, scientist and author of , when food is warmed up to room temperature or higher, it starts to deteriorate, and once it crosses a threshold - 160 degrees Celsius for meat, 140 degrees for fish - it tends to be dry and tough, no matter what you do.

Marion Nestle, professor of nutrition, food studies and public health at New York University, says the freezing, drying and storage of airline food are hard on flavour at any altitude, let alone 9,000 metres. She says ice cream is the only thing that tastes good on a plane.

In studying how aircraft noise affects the palate, Cornell University food scientists found it suppresses our sweet taste buds and amplifies those that recognise umami. A Japanese scientific term, umami describes the sweet, savoury taste of amino acids such as glutamate in foods like tomato juice. According to the new study, in noisy situations - like the 85 decibels aboard a jet - umami-rich foods become our taste bud's best buds.

Another study commissioned by German airline Lufthansa found that passengers were consuming as much tomato juice as beer. Based on its umami factor, tomato juice tastes better and far less acidic at a higher altitude than it does on the ground. Perhaps that's why Professor Barry Smith, founder of the Centre for the Study of the Senses at the University of London, says the best mid-air tipple is the Bloody Mary.

Staying hydrated before, during and after a flight is imperative to ease jet lag and fatigue. Admittedly, a few nips of alcohol may help with nodding off but wakefulness sets in within a few hours and shortens the deep sleep time.

Caffeine can be dehydrating and hampers your normal sleep cycle, making you feel sluggish when you reach your destination. Besides, a freshly brewed cup of tea tastes different in the air since water boils at 90 degrees Celsius due to the reduced cabin air pressure (instead of the normal 100 degrees Celsius), which interferes with the brewing process.

Instead of reaching for those miniature bottles of alcohol or caffeinated drinks, Karen Chong, registered dietitian at Matilda International Hospital recommends decaffeinated coffee, herbal tea, mint tea, chamomile tea and plain water. These also soothe the stomach.

Setting your watch to the time zone of your destination when you get on the plane can help mentally prepare you for where you're going. Physically, you'll begin to act, sleep and eat accordingly, which helps with the jet lag.

Anyway, most airlines give out meals according to the destination times, such as serving dinner at night before reaching the destination, or early breakfast if you're landing at the crack of dawn. That way you don't have to worry about adjusting your body clock to the new time zone.

According to researchers at Harvard Medical School, fasting before a long flight may help prevent jet lag. Our body's circadian clock in the brain dictates when to wake, eat and sleep, all in response to light.

But apparently a second clock takes over when we fast for about 16 hours, and manipulating this clock might help us adjust to new time zones. However, the experiment to prove this point was done on lab rats so its efficacy on humans is highly debatable.

Chong says being seated for long hours on a flight requires 5 to 10 per cent fewer calories than when you're on your feet, so you might want to cut back on some of the snacks. Instead, choose light meals with less sodium, sugar and fewer calories.

If you're carrying your own food, try and include lean proteins such as boneless, skinless chicken, turkey breast, hard-boiled egg whites and lean fish such as tuna. Avoid processed and fried foods, sugary items and white bread, since these foods tend to make you feel tired, unsettled and unsatisfied.

Some food tends to cause gastrointestinal discomfort such as gas pain and bloating, especially when physical activity is minimal on long-haul flight. Before the flight avoid consuming gas-producing food such as fizzy drinks, onion, garlic, potato, broccoli, dairy products and beans.

And, of course, food hygiene is very important. No one wants a gastrointestinal infection during a long-haul flight. Guard against such an occurrence by eating yogurt with natural probiotics that help regulate the digestive system.

Due to the numbing of our taste buds, airlines tend to salt and spice foods heavily to make them more appetising to passengers. But too much salt can cause water retention; moreover many of us tend to drink less water or other fluids to avoid going to the toilet frequently. All these will worsen the problem of water retention.

Consider adding a slice of lime to your glass of water. It is refreshing and the antibacterial properties of the citrus fruit can alleviate sore throats. Eat more fruit, as its a good source of hydration and healthy sugars. Oranges are a tasty source of vitamin C which helps boost your immune system and keeps you hydrated.