Those of us with an appetite for travel also tend to hold a special place in our stomachs for the culinary spoils that come with a getaway. Yet however tantalizing a destination’s delicacies may be, we usually squeeze in a couple of spare meals on the way. And not just because carbs don’t count above clouds.
During a trip, you might find yourself eating more on the fly.
Flights temporarily throw our relationship with food off kilter. There is no single reason, but scarcity, uncertainty and sleeplessness can have us biting off more than we’d normally chew. “Imagine being on a plane and NOT eating every item presented to you as if you will never again have ready access to food in your life,” tweeted New Yorker staff writer Jia Tolentino, possibly after polishing off an inflight meal. The sense that provisions are scarce in the sky may be part of the reason most passengers scarf down what’s given to them, regardless of appetite.
“Some evidence suggests that under conditions of uncertainty people are likely to consume more than usual or eat when they aren’t hungry,” says professor Michelle Lee, who heads a nutrition, appetite and cognition research group at Swansea University. While the theory has yet to be tested in a controlled travel scenario, a 2013 study by researchers at the University of Miami found that in a situation where rations seem rare, people are inclined to pack in extra calories.
Uncertainty about where the next meal is coming from isn’t the only issue at play. A growing smorgasbord of research shows that the larger the dinner party, the more diners dine. “Humans are very prone to the social–facilitation effect,” says Lee. This effect posits that you are more likely to engage in a certain behaviour in a group setting than if you were alone. “This applies with especial force to eating,” says professor Dick Stevenson, who studies appetite psychology at Macquarie University in Sydney, Australia.
The allure of overindulging can’t be overlooked either. Many of us eat more at buffets than we would ordering à la carte. “The inflight menu, food cart and your seatmate eating beside you can all tell your brain There is food here, and that signal can be hard to ignore,” says Dr. Christine Tenk, associate professor of psychology at Brescia University College in London, Ontario.
While external cues tell travellers to seize the buffet, lack of sleep and circadian disruption throw off internal cues, too. “A sleep–deprived brain craves more food because it doesn’t know how long it will be sleep– deprived,” explains Dr. Satchidananda Panda, who researches circadian regulation at the Salk Institute for Biological Studies in San Diego. Sleep loss also activates brain regions sensitive to food stimuli and can trigger hormone fluctuations that cause overeating.
For some holidaymakers, the anticipation of a trip is enough to whet their appetite – in other words, “when almost in Rome” is close enough. “Most of us loosen our inhibitions on vacation and eat more, and this can start on your flight to paradise,” says Dr. Tenk.
Fluctuations of these two hormones can throw hunger off balance both in–flight and on solid ground.
Ghrelin – The hunger hormone.Ghrelin is produced by cells mainly in the stomach that stimulate appetite in anticipation of a meal. While heavily researched, much about the craving–inducing hormone remains unclear. Studies show that levels of the hormone increase with lack of sleep or in response to stress.
Leptin – The satiety hormone.Leptin works in reciprocal rhythm with ghrelin as an appetite suppressant. While ghrelin levels recede after eating, leptin production in fat cells kicks into action to tell the brain the body is full. Research shows that leptin levels are reduced by sleep deprivation and exercise – and may even be responsible for triggering the brief state of euphoria known as runner’s high.