Researchers in South Korea compared the eating habits of 392 male workers—some who work regular daytime hours and others who work shifts at different times. They found that shift workers tend to eat at irregular times, skip meals, and buy more pre-made convenience foods like sandwiches and frozen meals. These shift workers also had lower overall nutrition scores, meaning their diets were less balanced. The study suggests that working irregular hours makes it harder for people to eat well, and that workplaces and health programs should offer better food options for shift workers.

The Quick Take

  • What they studied: How working different shifts affects what people eat and whether they buy pre-made meals instead of cooking at home
  • Who participated: 392 male workers in South Korea—193 who work shifts (nights, early mornings, or rotating schedules) and 199 who work regular daytime hours. The study took place between May and July 2024.
  • Key finding: Shift workers ate less healthy overall and bought convenience foods more often than regular workers. Their nutrition scores were noticeably lower, especially in eating a balanced variety of foods.
  • What it means for you: If you work shifts, you may need to plan your meals more carefully to eat healthier. Buying pre-made foods occasionally is fine, but relying on them too much can lead to a less balanced diet. This finding suggests employers should help shift workers access better meal options.

The Research Details

This was a cross-sectional study, which means researchers took a snapshot in time of two groups of workers and compared them. All 392 male workers filled out a detailed questionnaire about their eating habits, how often they bought pre-made meals, and other lifestyle factors like sleep quality and exercise. The researchers asked about meal timing, late-night eating, smoking, physical activity, and sleep quality. They also measured something called a ’nutrition quotient,’ which is a score that shows how balanced and healthy someone’s diet is overall.

The shift workers included people who worked nights, early mornings, or rotating schedules. The non-shift workers all worked regular daytime hours. Researchers used statistical tests to compare the two groups and make sure the differences they found were real and not just by chance.

Understanding how work schedules affect eating habits is important because shift work is becoming more common worldwide. If we know that shift workers struggle with healthy eating, we can design better solutions—like healthier food options at workplaces or nutrition education programs timed for shift workers. This research helps explain why some people find it harder to eat well, and it’s not just about willpower or personal choice.

This study has some strengths: it included a decent number of participants (392), used a structured questionnaire to collect information, and compared two similar groups. However, it only looked at male workers in one region of South Korea, so the results may not apply to women or people in other countries. The study was also done at one point in time, so we can’t say whether shift work causes poor eating or if people with poor eating habits are more likely to work shifts. The study relied on people reporting their own eating habits, which can sometimes be inaccurate.

What the Results Show

Shift workers showed several unhealthy eating patterns compared to regular workers. They ate at irregular times, ate late at night more often, and had poorer overall nutrition scores (48.75 out of a possible higher score versus 51.03 for regular workers). The biggest difference was in eating a balanced variety of foods—shift workers scored much lower in this area.

Shift workers also bought pre-made convenience foods much more frequently. They purchased gimbap and lunchboxes about 38% more often, sandwiches and burgers 19% more often, microwavable snacks 74% more often, and frozen fried rice 75% more often than regular workers. These pre-made foods are convenient but often higher in salt, sugar, and unhealthy fats.

The study also found that shift workers had other unhealthy lifestyle habits: they smoked more, exercised less, and reported worse sleep quality. These factors all work together to make it harder for shift workers to maintain good health.

Interestingly, shift workers and regular workers felt similarly about what they wanted in pre-made meals—both groups valued things like taste, nutrition, and convenience equally. This suggests that the problem isn’t that shift workers don’t care about nutrition; rather, their work schedules make it genuinely harder to eat well. The study also found that shift workers tended to have lower education levels and lower household incomes, which may make it even harder to afford fresh, healthy foods.

This research supports what other studies have shown: irregular work schedules disrupt eating patterns and make people more likely to rely on convenience foods. Previous research has linked shift work to weight gain, poor nutrition, and increased disease risk. This study adds to that evidence by showing specific foods that shift workers buy more often and confirming that their overall diet quality is lower.

This study only included men, so we don’t know if the same patterns apply to women shift workers. It only looked at workers in one region of South Korea, so results may differ in other countries with different food cultures and work practices. The study was done at one point in time, so we can’t prove that shift work causes poor eating—it’s possible that people with poor eating habits are more likely to work shifts. Finally, people reported their own eating habits, which can be inaccurate or biased.

The Bottom Line

If you work shifts: Try to eat at consistent times even if those times are unusual, keep healthy snacks available, and plan meals ahead when possible. Employers should consider providing healthier pre-made meal options for shift workers. Public health programs should create nutrition education specifically designed for people working irregular hours. These recommendations are supported by the research but should be combined with other healthy lifestyle changes.

This research is most relevant to shift workers, their employers, workplace health programs, and public health officials. If you work regular daytime hours, this may not directly apply to you, but it’s useful information if you have family members or friends who work shifts. Healthcare providers should be aware that shift workers may need extra support for healthy eating.

Changes in eating habits take time. If a shift worker starts planning meals better and choosing healthier options, they might notice improvements in energy levels within 2-4 weeks. More significant improvements in nutrition scores and overall health would likely take 2-3 months of consistent effort.

Want to Apply This Research?

  • Track meal times and pre-made food purchases weekly. Log when you eat (time of day) and how many times you bought convenience foods versus prepared meals at home. Aim to reduce convenience food purchases by 20-30% each month.
  • Use the app to set meal reminders for your specific shift schedule, create a weekly meal plan before your shifts start, and set a goal to prepare one home-cooked meal per day. Track which pre-made foods you buy most and find healthier alternatives.
  • Check your nutrition score monthly using the app’s nutrition assessment tool. Monitor your meal timing consistency, convenience food frequency, and overall diet variety. Compare your scores month-to-month to see if your eating patterns are improving.

This research describes patterns in how shift workers eat compared to regular workers, but it does not prove that shift work causes poor nutrition. Individual results vary greatly. If you work shifts and are concerned about your diet or health, consult with a healthcare provider or registered dietitian who can provide personalized advice based on your specific situation. This study was conducted in South Korea and may not apply to all populations or countries. Always speak with a medical professional before making significant changes to your diet or lifestyle.