Shift work – rotating shifts and night shifts – refers to work performed at alternating times of the day. Shift work affects both sleep patterns and food intake. It affects performance due to the different daily rhythms and often leads to stress. This can lead to burnout syndrome, disorders of the gastrointestinal tract (e.g. gastric ulcer), lipid metabolism disorders (hyperlipoproteinemia) and diabetes mellitus, as well as an increase in cardiovascular risks (e.g. high blood pressure). Furthermore, numerous studies have demonstrated an increased risk of tumor diseases (mammary carcinoma/breast cancer, prostate carcinoma/prostate cancer). The majority of shift workers also complain of sleep problems and fatigue. Diet has a major impact on work performance. Meal consumption as well as meal composition must be done at the right time.
Physiological and psychological conditions
All bodily functions of humans are subject to a day-night rhythm, which is innate to humans and difficult to influence. One speaks in this connection of the “internal clock”. During the day, the body switches to readiness for performance, and at night, the focus is on recovery and rest: pulse and blood pressure as well as the production of total digestive secretions and liver output decrease, and the need for warmth is significantly increased. Shift workers thus work against their biological rhythm. Understandably, performance in the evening and during the night does not match that of the day. An absolute performance low sets in around three o’clock at night, with the consequences that attention, the ability to concentrate and stamina drop significantly. The error rate is particularly high at this time.
Illnesses or disorders caused by shift work
The following diseases or disorders occur more frequently due to shift work, especially night work:
- Acceleration of aging processes in the brain, ie decrease in cognitive abilities.
- Immunodeficiency / susceptibility to infection
- Insomnia (sleep disorders)
- Mammary carcinoma (breast cancer)
- Prostate carcinoma (prostate cancer)
- Ulcus ventriculi (stomach ulcer)
Dietary recommendations for the rotating shift
When working alternating shifts, you work either the early shift – between 4 am and 1 pm – or the late shift – between 2 pm and 11 pm. On the early shift, two meals are eaten during working hours:
- A mid-morning snack
- A hot main meal at noon (equivalent to the lunch of the normal shift).
Two meals are also taken during working hours on the late shift:
- A snack in the afternoon
- Dinner (as a cold meal).
Dietary recommendations during the night shift
Night shift working hours are usually between 10 pm and 6 am. The dietary recommendations for night shift focus on a diet that is easily digestible, because the entire digestive tract is in a state of rest at night. The energy needs of a night shift worker are no different from those of a day worker. Only the distribution of energy intake is different, as shown in the following table:
| Meal | Recommended time | % of daily energy |
| Lunch | Between 12.00 and 13.00 | 25 |
| Snack | Between 16.00 and 17.00 | 10 |
| Dinner | Between 19.00 and 20.00 | 20 |
| 1st night meal | Between 0.00 and 1.00 a.m. | 25 |
| 2. night meal | Between 4:00 and 5:00 a.m. | 8 |
| Breakfast, at home | Between 7:00 and 8:00 a.m. | 12 |
Snacks between meals are important (as long as the night shift worker is not overweight), because they prevent the blood glucose level (blood sugar) from dropping too low, so that performance and concentration are favorably affected. Milk and dairy products, fruit and light salads are suitable as a snack. One of the two night meals should be prepared warm. The first night meal is the best choice here. A warm meal gives the feeling of inner warming, especially at night.Lunch and dinner should be eaten at the same time in each shift. This largely prevents loss of appetite and gastrointestinal disorders. In general, shift workers should introduce as much regularity as possible into their private lives, e.g. always go to bed at a fixed time after the end of the shift and get up at a fixed time. Notice. For shift workers who want to lose weight, the same rules for a calorie-reduced and whole-food diet apply as for day workers.