Compared to individuals who work during the day, shift workers are at higher risk of a range of metabolic disorders and diseases (eg, obesity, cardiovascular disease, peptic ulcers, gastrointestinal problems, failure to control blood sugar levels, and metabolic syndrome). At least some of these complaints may be linked to the quality of the diet and irregular timing of eating, however other factors that affect metabolism are likely to play a part, including psychosocial stress, disrupted circadian rhythms, sleep debt, physical inactivity, and insufficient time for rest and revitalization. In this overview, we examine studies on food and nutrition among shift workers [ie, dietary assessment (designs, methods, variables) and the factors that might influence eating habits and metabolic parameters]. The discussion focuses on the quality of existing dietary assessment data, nutritional status parameters (particularly in obesity), the effect of circadian disruptions, and the possible implications for performance at work. We conclude with some dietary guidelines as a basis for managing the nutrition of shift workers.

Background: Because of changing food habits that may influence nutritional status it is important, especially in children, reproducibly to describe and analyse the timing and frequency of eating and the composition of different types of eating episodes. Objective: To describe eating patterns of 3-5-year-old Swedish preschool children by analysing 7 day food records using the Food-Based Classification of Eating Episodes (FBCE) model. Design: Food intakes were categorized into four types of "meals" and four types of "snacks", according to their food profile. Complete 7 day weighed and estimated food records for 109 children were processed and analysed. Results: On weekdays the children ate significantly more frequently than on weekend days, having 5.6 and 5.2 eating episodes per day, respectively. More eating episodes were classified as "meals" on weekdays than on weekend days: 72% and 60%, respectively. On average for the whole week, 43% of the daily energy intake was derived from "complete meals" (CM) and 34% from "incomplete meals" (IM). CM contributed significantly more energy and more nutrients, except for calcium, than did IM. In low-quality snacks (LS), sucrose contributed with about one-third of the energy content and the nutrient density was low. Conclusions: The qualitative FBCE model verified nutritional characteristics of the children's diet previously found in the same cohort by the traditional dietary assessment methods. Processing of the dietary data by the model to show the prevalence and temporal distribution of eating episodes appears to be an applicable tool for nutritional screening of children's eating patterns

The purpose of this investigation was to evaluate the acute effects of missing a meal on alertness. The participants were ten university students between 20–29 years old, five females and five males. Participants were chosen on the basis of their good sleep and eating practices. Measurements were collected during an eight hour period starting at 8.00 AM on four separate days. During the test period, participants carried out their normal study activities while on separate days receiving either just breakfast, just lunch, both lunch and breakfast, or no meal at all. During the test period, EEG was monitored continuously while subjective ratings of performance and tiredness were collected every half-hour. The results showed that while there were neither physiological nor subjective indications of tiredness which could be attributed to meal consumption, subjective feelings of lack of energy and motivation was significantly more pronounced at the end of the workday when missing a meal or two.

This study investigated the effects of high-carbohydrate (HC) and high-fat (HF) diet on cognitive performance, and subjective and objective sleepiness. Seven male participants were kept awake for 24h in a metabolic ward. Meals were given every 4h and cognitive performance and sleepiness ratings were assessed hourly. The Karolinska Drowsiness Test (KDT, EEG derived) was performed twice after meal. Performance in simple reaction time showed a significant interaction of diet and the post-prandial period, a slower reaction time was observed for the HC-diet 3.5h after meal intake. Diet did not affect EEG measures but a general post-prandial increase of objective sleepiness was observed 3.5h after meal servings. The HC-diet was significantly associated with an increase of subjective sleepiness. The study demonstrated that the HC-diet caused larger oscillation in performance and increased sleepiness as compared to HF-diet throughout day and night.

Background: Night work is becoming more common and shift workers display several metabolic disturbances. Aim: To study the endocrine responses in relation to time of day during a 24-h period and how dietary macronutrient composition affects these responses. Design: Seven males (26-43 y and 19.9-26.6 kg · m-2) were studied in a crossover design. Isocaloric diets described as highcarbohydrates (HC; 65 energy percent (E%) carbohydrates and 20E% fat) or high-fat (HF; 40E% carbohydrates and 45E% fat) were given. After a 6-day diet adjustment period, the subjects were kept awake for 24 h in a metabolic unit and were served an isocaloric meal (continuation of respective diet) every 4-h. Blood samples were taken throughout the 24-h period. Results: Insulin and leptin responses to meal intake differed with respect to time of day (p ≤ 0.05). Time of day affected glucagon, thyroid stimulating hormone (TSH), free thyroxin (fT4), total triiodothyronine (tT3), cortisol, chromogranin A (CgA) and pancreatic polypeptide (PP) concentrations (p ≤ 0.05). Meal intake decreased cortisol concentration after meals at 0800, 1200 and 0400 but not at 1600, 2000 and 0000 h. The PP's postprandial increase was greater during 0800-1600 h compared to 2000-0800 h. With the HC meals, lower glucagon and CgA concentrations (p ≤ 0.05), and a tendency for lower tT3 concentrations (p = 0.053) were observed compared to the HF meals. Conclusion: Insulin, PP, TSH, fT4, cortisol and leptin responses to meal intake differed with respect to time of day. The decreased evening/nocturnal responses of cortisol and PP to meal intake indicate that nocturnal eating and night work might have health implications.