The Venn diagram of shiftwork and health is two separate circles that do not overlap in any way. For those of you who don’t know what it’s like to find yourself face down in a bag of Doritos at 4am whilst an onslaught of patients descend upon you like the hyenas in The Lion King, you’re not missing out. It can be incredibly difficult to maintain a healthy diet on shift – and is it really all your fault?

Shiftwork: How to Die Young

Shiftwork is not the one. Associated with a whole host of stunning life-shortening conditions like increased cardiovascular disease risk, diabetes and obesity (Ha and Park, 2005), it is no surprise that it is recommended we avoid it (Liu et al., 2018). But because a girl’s gotta eat, it’s unavoidable for many, so avoidance isn’t helpful public health advice.

Whilst we cannot control working shifts, we can control our diet. Diet is a powerful modifiable risk factor for many cardiovascular and metabolic diseases (Djousse et al., 2010). So, whilst shiftworkers cannot control circadian disruption from being awake all night, they can mitigate this impact through maintaining a healthy diet.

Sounds good, right?

One massive problem – shiftworkers typically have terrible diet patterns.

Elevated saturated fat intake, lower fibre intake, higher processed food intake and lower vitamin/mineral intake (Nea et al., 2015). Not a vibe. It is very easy to say ‘jUsT eAt hEaLtHy’, and obviously in an ideal world we would all be eating our superfood salad garnished with kale handpicked by Tibetan monks riding unicorns. But that’s not realistic for shiftworkers. There are a number of internal and external barriers to eating a healthy diet for the shiftworker. Let’s get into it.

Intrinsic Factors Affecting Dietary Choices

Circadian Disruption

We covered circadian rhythm and disruption here, so I won’t get too into it. However, disrupting the sleep-wake circadian rhythm also disrupts leptin and ghrelin release (Scheer, Morris and Shea, 2013). Leptin and ghrelin are often referred to as the “hunger” hormones, and influence the desire to eat and satiety (feeling “full”) (Klok et al., 2006).

Indeed, one study found that morning shift workers had higher leptin and lower ghrelin levels than night shift workers (Crispim et al., 2011). Now, it is important to note that this study had a small sample size (n=22), and ghrelin and leptin levels are influenced by a whole host of factors, not only circadian rhythm.

We know for sure that sleep deprivation affects hormonal appetite regulation (Fradkin et al., 2018). So, there is the possibility that shiftwork disrupts hormonal appetite regulation, and makes us feel hungrier at night.

The Energy Cost of Being Awake

Another reason why night shift workers tend to consume more calories (Fradkin et al., 2018), can be simply the fact there’s more to do. This is particularly evident in healthcare settings. Patients tend to selfishly remain ill outside of the hours of 9-5, and consequently healthcare facilities are required to provide 24 hour care. In healthcare, there can be less staff available for “out of hours” care. This is evident in literature, with many hospitals typically having higher numbers of staff during the day, and less at night (de Cordova et al., 2014).

Less staff and more work to be done results in more energy being expended. Consequently, you might find yourself researching for a sugary hit of energy to keep you going.

Stress & Tiredness

Extended working days are not good for the will to live. Stress, tiredness and poor dietary choices go hand in hand. Stress is associated with increased emotional eating and disrupted hunger/fullness signals (Tan and Chow, 2014). Night shift workers tend to be more sleep deprived than their day shift counterparts (Ko, 2013). They also tend to suffer from “sleep debt” and “social jetlag”, which is a mismatch in hours slept and hours required (Brum et al., 2020). These phenomena are associated with obesity, potentially because of the increased emotional eating.

Interestingly, we also tend to feel more tired in the second half of night shifts (Baulk et al., 2007).This may be something to consider when planning for your next night shift, and try and eat during your shift if possible, if this is an issue for you.

External Factors Influencing Dietary Choices

These factors vary hugely between individuals, and are more anecdotal and less studied, due to the sheer inter-individual variation.

Workplace Facilities

 A common issue facing many shift workers is the lack of facilities for meal preparation/storage. Canteens and kitchens in many workplaces are locked at night, and consequently, workers have no access to fridges or microwaves to store or heat meal prep (Nea et al., 2017). This can be a major barrier, and in many cases leaves workers with no choice but to go for packaged convenience foods.

Accessibility of Food

In addition to having suboptimal facilities to store and prepare food, many shift workers face the problem of having no access to healthier food unless they prepare it at home (Gupta et al., 2019). Canteen and coffee shops in most workplaces do not open 24/7, and in many cases there is no option but to bring in your own food. Your options are limited to the vending machine, which isn’t exactly stocked full of your five a day. If I’m on a 20 hour shift, with nothing to do but make eyes at a Club Milk, you can bet your ass I won’t forego it for the Granny Smith burning a hole in my bag.

Then comes the next problem – access to supermarkets. For many shift workers, shops in their area do not open early enough for them to go on their way home (Nea et al,. 2017). After a long night, I am like a demon. I am not going to wait for the shop to open, I am going home to pass out and question all my life decisions. This makes it difficult to get access to healthier food for meal preparation.

Breaktimes, Or Lack Of

Now, I’m not trying to say we don’t all get our assigned legal breaks. But, hypothetically, if you are extremely busy all night running around after people, you eat when you can. You may not be able to sit down and eat a full meal uninterrupted. You’re grabbing convenience food, and often that means delicious sugary goodness.

It’s not really realistic to follow the guidance of “sit down and eat mindfully and slowly without distraction”, when you have patients arresting and you’re the only one on shift. You need to do what you can, and sometimes that’s a sugary snack.

Culture

This is a big one, and one I have experienced to varying degrees in the different hospitals I have worked in. There can be a culture of “having” to eat takeaways and hyperpalatable sugary goodness on shifts (Nea et al., 2017). It is extremely difficult to decline all of these stunning foods if everyone else is getting involved. It is not fun to be the person that pulls out their meal prep when all around you are spicebags and pizza. Now, this isn’t the case everywhere, and on shifts where you’re the only person there, it’s a lot easier to say “no”. But it’s definitely something to bear in mind.

Conclusion

Shiftwork nutrition is one of the most complex issues to tackle, because there are so many factors that influence our choices – many of which are beyond our control. Hopefully, this will help you to go a little easier on yourself the next time you feel bad for choosing chocolate over kale at 4am, and help you identify where you can make improvements in your diet.

Of course, it was not possible to cover everything here, so let me know if there’s anything you think I missed!

For more information on chrononutrition, I highly recommend following Alan Flanagan, who is very much the expert.

References

• Baulk, S.D., Kandelaars, K.J., Lamond, N., Roach, G.D., Dawson, D., Fletcher, A. (2007) ‘Does variation in workload affect fatigue in a regular 12 hour shift system?’, Sleep and Biological Rhythms, 5, pp. 74-77.
• Brum, M.C., Dantas-Filho, F.F., Schnorr, C.C., Bertoletti, O.A, Bottega, G.B., Rodrigues, T. (2020) ‘Night shift work, short sleep and obesity’, Diabetology & Metabolic Syndrome, 12(13).
• Crispim, C.A., Waterhouse, J., Dâmaso, A.R., Zimberg, I.Z., Padilha, G., Oyama, L.M., Tufik, S., De Mello, M.T. (2011) ‘Hormonal appetite control is altered by shift work: a preliminary study’, Metabolism, 60(12), pp. 1726-1735.
• De Cordova, P.B., Phibbs, C.S., Schmitt, S., Stone, P.W. (2014) ‘Night and Day in the VA: Associations between Night Shift Staffing, Nurse Workforce Characteristics, and Length of Stay’, Research in Nursing & Health, 37(2), pp. 90-97.
• Djousse, L., Padilla, H., Nelson, T.L., Gaziano, J.M., Mukamal, K.J. (2010) ‘Diet and Metabolic Syndrome’, Endocrine, Metabolic & Immune Disorders-Drug Targets, 10(2), pp. 124-137.
• Fradkin, L., Raz, O., Boaz, M. (2018) ‘Nurses who work rotating shifts consume more energy, macronutrients and calcium when they work the night shift versus day shift’, Chronobiology International, 1(1), pp. 1-8.
• Gupta, C.C., Coates, A.M., Dorrian, J., Banks, S. (2019) ‘The factors influencing the eating behaviour of shiftworkers: what, when, where and why’, Industrial Health, 57(4), pp. 419-453.
• Ha, M., Park, J. (2005) ‘Shiftwork and Metabolic Risk Factors of Cardiovascular Disease’, Journal of Occupational Health, 47(2), pp. 89-95.
• Klok, M.D., Jakobsdottir, S., Drent, M.L. (2006) ‘The role of leptin and ghrelin in the regulation food intake and body weight in humans: a review’, Obesity Reviews, 8(1), pp. 21-34.
• Ko, S.B. (2013) ‘Night Shift Work, Sleep Quality and Obesity’, Journal of Lifestyle Medicine, 3(2), pp. 110-116.
• Liu, Q., Shi, J., Duan, P., Liu, B., Li, T., Wang, C., Li, H., Yang, T., Gan, Y., Wang., X. (2018) ‘Is shift work associated with higher risk of overweight or obesity? A systematic review of observational studies with meta-analysis’, International Journal of Epidemiology, 47(6), pp. 1956-1971.
• Nea, F.M., Kearney, J., Livingstone, B.E., Pourshahidi, K., Corish, C.A. (2015) ‘Dietary and lifestyle habits and the associated health risks in shift workers’, Nutrition Research Reviews, 28(2).
• Nea, F.M., Pourshahidi, K. Keaney, J., Livingstone, B.E., Bassul, C., Corish, C.A (2017) ‘Qualitative Exploration of the Shift Work Experience: The Perceived Barriers and Facilitators to a Healthier Lifestyle and the Role of the Workplace Environment’, Journal of Occupational and Environmental Medicine, 59(12), pp. 1153-1160.
• Scheer, F.A., Morris, C.J., Shea, S.A. (2013) ‘The Internal Circadian Clock Increases Hunger and Appetite in the Evening Independent of Food Intake and Other Behaviors’, Obesity, 21(3), pp. 421-423.
• Tan, C.C., Chow, C.M. (2014) ‘Stress and emotional eating: The mediating role of eating dysregulation’, Personality and Individual Differences, 66, pp. 1-4.