It�s no accident that most of us tend to sleep at night and wake at daybreak. As a result, we get hungry at specific times throughout the day. It�s a natural cycle that is innate in us humans.

Have you ever wondered what happens to your body when this natural cycle is disrupted? Especially for shift workers clocking irregular hours in the long run, pulling all-nighters, eating at odd hours of the day, and how such lifestyle affects one�s nutrition and health?

Nutritional implications of an altered circadian rhythm

Shift work can be detrimental to the health of workers because it interferes the body�s circadian rhythm, also known as our �body clock�. Its role is to tell our body the right time to sleep, to wake up, to feel hungry, to release certain hormones and carry out many other essential functions within a 24-hour cycle. When a worker has irregular shifts that alter the time they eat and sleep, such as an overnight shift, it causes disruption to the circadian rhythm.

Research has found that the human body is designed to expend more energy in the day than in the night due to the circadian rhythm. As a result, workers on night or irregular shifts expend less calories in the middle of the night after a meal. This leads to weight gain since excess calories are stored as fat reserves. Coupled with the fact that there are metabolic disturbances such as glucose intolerance, insulin resistance and dyslipidaemia as the circadian rhythm is disturbed, this will cause the worker to gain even more weight and predispose them to type 2 diabetes.

Shift workers tend to eat meals or snacks late at night but the body is programmed to be in fasting mode during this time (according to the circadian rhythm!), and it does not expect to receive an intake of food. So, when a worker eats late at night during a night shift, the body gets confused and ends up generating an abnormal metabolic response within the body, compared to when the food is eaten during the day. When this happens repeatedly over a prolonged period, it becomes a risk factor for cardiovascular disease and diabetes.

Furthermore, a disrupted circadian rhythm can cause shift workers to experience decreased cognitive abilities, poor reflexes and poor decision making due to fatigue. It can also increase the risks of mental health disorders and sleep disorders.

How else does shift work sabotage a worker�s nutrition?

There are other factors that can contribute to the negative nutritional impacts of shift work besides a disrupted circadian rhythm:

• Working irregular hours means less time preparing food to take to work, this means that workers must buy takeaway. Convenient takeaway choices are usually not healthy. Workers may be tempted to go to convenience stores or fast-food restaurants just because it is nearer to their workplace. They may even purchase food from an office vending machine, which is usually highly processed and contains many preservatives.
• Meals provided to them by their companies may not be as nutritious.
• Lack of healthy snacks available at the workplace.
• Due to social influence from co-workers, workers may be tempted to buy unhealthy takeaway with their colleagues.
• After a long night shift, tired workers prefer easy-to-prepare meals or something quick and easy to eat, which are usually lacking in nutritional quality.
• Meals might be delayed or missed during a busy shift. For example, breakfast might be missed if the ending night shift is delayed.

However, the good news is that by taking measures to counter these adverse impacts, the worst can be prevented.

Healthy eating guidelines to survive shift work

Here are some tips from Active Health Coach Nur Azlina, on ways that shift workers can eat healthier:  

1. Include plenty of lean proteins and fibres for your main meal before your shift. These foods prolonged the feeling of fullness even after the meal, controlling your overall caloric intake.
2. Keep a healthy snack pack! Fill it with wholemeal crackers, packets of unflavoured milk, portioned nuts and fresh fruits (bananas, oranges and apples). These options can reduce the temptations of unhealthy snacks.
3. Drink plenty of water and always carry a water bottle with you during your shifts. Choosing water instead of sugary drinks and alcohol helps to reduce intake of liquid calories, helps in digestion and optimal muscle function. If you find it difficult to drink just plain water, you can consider adding some fruits to your water to give it some flavour which makes it tastier to drink!
4. Avoid drinking coffee and tea six hours before sleeping to allow sufficient time for the caffeine to wear off.
5. Stick to eating at regular times even during night shift / prolonged shift work. This will help the circadian rhythm to regulate and readjust.

The human body is not built to handle shift work, especially those with schedules that keep changing. However, with sufficient knowledge, good guidelines, discipline and the effort to commit to change, one can better manage and prevent the negative effects that shift work has on one�s health. For more tips to Eat Better, sign up for one of our Nutrition e-workshops.