April 15, 2024

The science of Chrononutrition

Dietitian and frequent flyer Melissa Adamski, the founder of Nutted Out Nutrition, looks at using food to reduce jet lag…

Jet lag could be reduced if airlines, caterers and passengers embrace the nutritional science of chrononutrition – essentially the study of diets and circadian rhythms. 

Characterised by daytime fatigue and alertness at night, jet lag sometimes extends to gastrointestinal issues and is caused by a de-synchronisation or misalignment of our circadian rhythms – including the body’s sleep/wake cycles – to the new time zone. Basically, our internal body clocks become confused when we cross time zones because external cues, including light, tell our bodies it is a different time to what our body clock thinks it is.

Embracing chronobiology

Generally, it takes a few days for circadian rhythms to align with a new time zone. The science of chronobiology gives flyers tips relating to which factors help realignment.

One of the best-known external cues to help resync circadian rhythms – or zeitgebers as they are known – is exposure to daylight. Getting out into the sunshine is a helpful strategy to adjust to a new time zone. 

Eating is also considered a zeitgeber. For airlines operating long-haul flights across multiple time zones, that opens new possibilities in passenger service.

 Our dietary patterns and the foods that we eat can affect jet lag. So airlines and caterers should reassess the foods served during long flights. 

Circadian rhythms tell us that nighttime is for resting but they are about more than just sleeping to reduce how tired we feel. They also influence digestion and the metabolism of food. The production of gastric enzymes and fluids, nutrient absorption and gut motility all reduce during the night cycle or sleep period. 

So when we eat in the daytime our body processes food differently from when we dine at night. Essentially, the same food eaten at 3.00pm amd 3.00am has different effects.

Research from 2019 shows that the human body does not metabolise carbohydrates as well when they are eaten at night, resulting in larger increases in blood sugar levels. This is believed to be among reasons why shift workers have a higher risk of developing Type 2 diabetes.

Gut motility also slows down, meaning we don’t digest food as well at night. This can cause gastrointestinal issues such as bloating. Yet eggs offset the effects of eating carbohydrates when the body thinks it’s night and fruit such as blueberries, oranges, kiwi fruits and pineapple are less likely to cause bloating.

Overall, chrononutrition research is highlighting that, for good health, when we eat is as important as the what and how much.

There is still much to be understood before a specific anti-jet lag diet is developed but it’s not too early for airlines to take action to support passengers. Existing chrononutrition-related research suggests that dietary strategies could help reduce jet lag symptoms and assist travellers in resynchronising their body clocks. 

Airlines and caterers could start by personalising catering options specifically to time zone changes and time of day at origin and destination. Giving passengers more flexibility over meals would also help. 

Translating the concepts of chrononutrition into practicalities may seem complex. Yet it can be simplified by considering four areas for onboard catering innovation: meal timings, frequency, size and nutrient composition.

Interest from passengers 

Supporting passengers to step off a long-haul flight with barely a hint of jet lag could be a factor in winning repeat custom. Offering passengers insights about dietary changes – before, during and after flying – could be a positive first step in lieu of changing catering. 

Australian research into behaviour to reduce jet lag and travel fatigue on long-haul flights found that nearly 70% of passengers made changes to foods eaten, including eating healthier or changing meal sizes. These insights into passenger behaviour suggest an underlying interest in using food to help reduce jet lag.

Airlines and caters can innovate in meal design, onboard services, passenger education and research to prevent jet lag, making this an area with exciting potential.