If you work at night, you’ve probably noticed that your appetite plays by its own rules. You might feel starving at 2 a.m., completely uninterested in food at sunrise, and suddenly ravenous again when you’re supposed to be sleeping. Cravings tend to skew toward carbs, sugar, or salty snacks, and “normal” meal timing falls to the wayside. This is not actually a lack of discipline, but a biological response.

Your body runs on a circadian rhythm, a roughly 24-hour internal clock, that regulates sleep, hormone release, digestion, and metabolism. This clock is heavily influenced by light and darkness. When you work nights, you’re asking your body to eat, stay alert, and perform during a window that has been biologically labeled as “rest and repair.”

Two hormones play a starring role in appetite: ghrelin and leptin. Ghrelin stimulates hunger, while leptin signals fullness. Under normal circumstances, these hormones rise and fall in predictable patterns tied to sleep and daylight. Night shift work disrupts that rhythm. 

Cortisol also joins the chaos. This stress hormone naturally peaks in the morning to help you wake up. For night shift workers, cortisol rhythms can flatten or shift, staying elevated at odd hours. Elevated cortisol increases appetite and promotes insulin resistance over time – this is why night shift cravings often lean toward sugary snacks or ultra-processed foods.

Insulin sensitivity is another piece of the puzzle. Your body handles glucose best during the daytime. Eating large meals at night, when insulin sensitivity is lower, can lead to higher blood sugar levels and increased fat storage. 

Fatigue makes everything worse. Sleep deprivation further disrupts hunger hormones, increasing appetite and reducing impulse control. Your body wants quick sources of energy, and those are found in carb-heavy foods, so your cravings are driven by seeking a pick-me-up. After a long shift, your brain is tired, your hormones are off, and the vending machine starts looking emotionally supportive.

So what helps? You don’t need a perfect diet, but smarter strategies! Many night shift workers do better with a larger, balanced meal before the shift, lighter snacks during the night (and planning ahead for these snacks by bringing food and not relying on vending machines or quick buys), and avoiding heavy meals right before sleep. 

Protein and fiber help stabilize blood sugar and reduce cravings, so plan overnight snacks featuring both – fruit, nuts, yogurt, hardboiled eggs. Try to avoid sugary and salty snacks which could trigger a craving for more of those when your brain feels the temporary energy boost.

Staying hydrated also matters more than you think, since dehydration often masquerades as hunger. And giving yourself grace is essential as your body is adapting to an unnatural schedule.

So if you work at night, know that weird appetite on the night shift isn’t a personal failure, but a hormonal mismatch. Understanding what your body is doing helps you work with it instead of fighting it, one snack decision at a time.

References:

McEwen, B. S. (2007). Physiology and neurobiology of stress and adaptation: Central role of the brain. Physiological Reviews, 87(3), 873–904.
https://doi.org/10.1152/physrev.00041.2006

Qian, J., & Scheer, F. A. J. L. (2016). Circadian system and glucose metabolism: Implications for physiology and disease. Trends in Endocrinology & Metabolism, 27(5), 282–293.
https://doi.org/10.1016/j.tem.2016.03.005.

Scheer, F. A. J. L., Hilton, M. F., Mantzoros, C. S., & Shea, S. A. (2009). Adverse metabolic and cardiovascular consequences of circadian misalignment. Proceedings of the National Academy of Sciences, 106(11), 4453–4458.
https://doi.org/10.1073/pnas.0808180106.

Wright, K. P., Jr., Drake, A. L., Frey, D. J., et al. (2015). Influence of sleep deprivation and circadian misalignment on cortisol, inflammatory markers, and cytokine balance. Brain, Behavior, and Immunity, 47, 24–34.
https://doi.org/10.1016/j.bbi.2015.01.004.