A large study of over 15,000 Korean workers found that people who work night shifts or irregular hours tend to have worse eating habits than those who work regular daytime jobs. Shift workers were more likely to skip breakfast and eat fewer fruits, vegetables, and protein-rich foods. Interestingly, they did eat less salt, which is actually good for health. The researchers suggest that shift workers need special help to eat better meals at regular times, since their unusual work schedules make it harder to maintain healthy eating patterns.

The Quick Take

  • What they studied: Whether people who work night shifts or changing schedules eat differently and less healthily than people who work regular daytime hours
  • Who participated: Over 15,000 Korean workers aged 20 and older who answered questions about their work schedules and what they ate during a national health survey between 2013 and 2021
  • Key finding: Shift workers skipped breakfast more often and ate less fruit, vegetables, and protein compared to day workers, though their overall diet quality scores were similar. Shift workers did consume less salt, which is beneficial.
  • What it means for you: If you work night shifts or changing hours, you may need to be more intentional about eating regular meals, especially breakfast, and including more fruits, vegetables, and protein in your diet. This finding suggests that shift work schedules make healthy eating harder, so planning ahead is important.

The Research Details

Researchers looked at information from a large national health survey in South Korea that tracked what people ate and their work schedules. They compared the eating habits of shift workers (people working nights, early mornings, or rotating schedules) to regular daytime workers. They used a special scoring system called the Korean Healthy Eating Index to measure diet quality, which looks at how well people follow healthy eating guidelines. The researchers used statistical methods to account for other factors that might affect eating habits, like age, income, and education level.

This research approach is important because it looks at real-world eating patterns from a large, representative group of workers rather than just a small sample. By comparing shift workers to day workers and separating the results by gender, the researchers could identify specific eating problems that shift workers face. This helps explain why shift work might increase health risks.

This study is based on a well-established national health survey that represents the Korean population. The large sample size of over 15,000 people makes the findings more reliable. However, because people reported their own eating habits from memory, there could be some inaccuracy. The study shows what eating patterns exist but cannot prove that shift work directly causes poor eating habits.

What the Results Show

Shift workers did not have significantly worse overall diet quality scores compared to day workers, which was somewhat surprising. However, when researchers looked at specific foods, clear differences emerged. Shift workers were about 22% less likely to eat breakfast regularly, 14% less likely to eat fresh fruits, 11% less likely to eat vegetables (excluding pickled items), and 13% less likely to eat protein-rich foods like meat, fish, and beans. On the positive side, shift workers consumed less sodium (salt), which is actually beneficial for heart health and blood pressure. When the researchers separated the results by gender, they found that male shift workers ate less fruit, while female shift workers had more problems with skipping breakfast and eating less fruit and protein.

The gender differences were notable and suggest that shift work affects men and women differently. Women working shifts appeared to struggle more with meal regularity and protein intake, while men primarily had issues with fruit consumption. These differences might be due to different work schedules, family responsibilities, or cultural factors in how men and women approach meals.

This study confirms what previous research has suggested: shift work disrupts normal eating patterns. The finding that shift workers skip breakfast more often aligns with other studies showing that irregular schedules interfere with meal timing. The lower intake of fruits, vegetables, and protein matches patterns seen in other countries’ shift worker populations. The better sodium intake among shift workers is an interesting finding that differs from some previous research and may be specific to Korean dietary patterns.

The study only looked at Korean workers, so findings may not apply to other countries with different food cultures and work practices. Because people reported what they ate from memory, there may be errors in the data. The study shows that shift workers eat differently but cannot prove that shift work causes these eating habits—other factors like personal preferences or economic status could play a role. The study was conducted over several years, and eating habits may have changed since then.

The Bottom Line

If you work shift hours, try to: (1) Plan and prepare meals in advance so you have healthy options available during odd hours, (2) Make breakfast a priority even if it’s at an unusual time, (3) Include fruits, vegetables, and protein sources in every meal or snack, (4) Keep healthy snacks like nuts, yogurt, or cut vegetables readily available. These recommendations are based on solid evidence but should be adapted to your specific work schedule and circumstances.

This research is most relevant to people who work night shifts, early morning shifts, or rotating schedules. It’s also important for employers, occupational health professionals, and healthcare providers who work with shift workers. If you work regular daytime hours, these findings are less directly applicable to you, though maintaining regular meal times is good advice for everyone.

Changes in eating habits typically take 2-4 weeks to establish as new routines. You might notice improved energy levels within a few days of eating more regular meals and including more protein. More significant health benefits like better weight management or improved blood sugar control usually take 2-3 months of consistent healthy eating.

Want to Apply This Research?

  • Track meal timing and completion for one week, specifically noting: (1) Whether you ate breakfast and what time, (2) Number of servings of fruits and vegetables consumed daily, (3) Protein sources eaten at each meal. This creates a baseline to see patterns and identify which meals are most often skipped.
  • Set phone reminders for meal times that match your shift schedule (even if breakfast is at 2 PM). Use the app to plan your meals for the week before your shifts start, including specific fruits, vegetables, and proteins. Create a simple shopping list in the app based on your planned meals to ensure you have healthy options available.
  • Weekly review of meal regularity and food group intake. Set a goal to increase fruit/vegetable servings by one per day each week. Track breakfast completion rate and aim for 80% consistency. Monthly check-ins to assess energy levels, sleep quality, and overall wellbeing as eating habits improve.

This research shows associations between shift work and eating patterns but does not prove that shift work causes poor eating habits. Individual results vary based on personal circumstances, genetics, and other lifestyle factors. If you have specific health concerns or dietary restrictions, consult with a healthcare provider or registered dietitian before making significant changes to your eating habits. This information is for educational purposes and should not replace professional medical or nutritional advice.