This study aimed to identify meal and snack patterns and assess their association with sleep timing in schoolchildren. This is a cross-sectional study carried out in 2018/2019 with 1333 schoolchildren aged 7–14 years from public and private schools in Florianópolis, Brazil. Previous-day dietary intake data for breakfast, mid-morning snack, lunch, mid-afternoon snack, dinner and evening snack were collected using a validated online questionnaire. Sleep timing was measured by the midpoint of sleep and classified as quartiles (very early, early, late and very late). Latent class analysis was performed to identify meal and snack patterns, and multinomial logistic regression was used to assess associations. Students with very late sleep timing were less likely to consume the ‘coffee with milk, bread and cheese’ breakfast pattern compared with very early group. Also, the former were more likely to consume the ‘mixed’ breakfast pattern (healthy and unhealthy foods) compared with very early students. The latter were more likely to eat the ‘Brazilian traditional, processed meat, egg and fish’ lunch pattern to the late students and less likely to consume the ‘pasta and cheese’ lunch pattern compared with the students with later sleep timing. Students with later sleep timing were more likely to eat ultra-processed food at mid-afternoon snacks compared with early group. The study findings suggest that morning preference appears to promote healthier breakfast, lunch and afternoon snack patterns, whereas later sleep timing may pose challenges in maintaining healthy patterns at these meals/snacks.

The primary aim of this study was to examine the association between snack nutritional quality, overall diet quality and adiposity among Australian adolescents. The secondary aim was to assess the distribution of discretionary foods (i.e. energy-dense and nutrient-poor foods and beverages) and intakes from the five food groups at different levels of snack nutritional quality. Dietary data collected from nationally representative adolescents (12–18 years old) during a 24-h dietary recall in the National Nutrition and Physical Activity Survey were analysed (n 784). Snacks were defined based on participant-identified eating occasions. Snack nutritional quality was assessed using the Nutrient Profiling Scoring Criterion (NPSC), whereas diet quality was evaluated using the Dietary Guideline Index for Children and Adolescents. Adiposity was assessed through BMI Z-score waist circumference and waist:height ratio (WHtR). Higher nutritional quality of snacks, as assessed by the NPSC, has been associated with higher diet quality among both boys and girls (P < 0·001). However, there is no association between snacks nutritional quality with BMI Z-score, waist circumference and WHtR. Among both boys and girls, the consumption of fruits, vegetables and legumes/beans at snacks increased with improvement in snack nutritional quality. Conversely, the consumption of discretionary foods at snack decreased with improvement in snack nutritional quality. In conclusion, improved snack quality was associated with better diet quality in adolescents. However, there was no association between snack nutritional quality and adiposity. Future, snack nutrition quality indices should consider optimum snack characteristics related with adiposity and diet quality.

Snacking is a common eating behaviour among adolescents accounting for more than a quarter of their total energy intake but the relationship between snacks and overall diet quality remains unclear(1). Hence, the aim of this study was to examine characteristics of snacks among Australian adolescents (12-18 years) according to their level of diet quality. This secondary analysis uses one day of 24-hour dietary recall data from the 2011 - 2012 National Nutrition and Physical Activity Survey (n = 935). Snacks were defined based on participant-identified eating occasions(2). The Dietary Guideline Index for Children and Adolescents (DGI-CA) was used to assessed adherence to the Australian Dietary Guidelines(3), with the highest tertile of the DGI-CA score indicating high adherence. The means (95% confidence intervals [CI]) for daily snack frequency and snack energy density (ED; kJ/g) were estimated for boys and girls, using linear regression, adjusted for age, area-level disadvantage, and energy misreporting. The differences in means and proportions across tertiles of DGI-CA scores were tested by using F- and Chi square-tests, respectively. The results show no significant differences in the mean frequency of snacks across tertiles of DGI-CA scores in either boys (lowest tertile mean = 2.2, 95% CI [2.0, 2.4] snacks/day, highest tertile = 2.1 [1.9, 2.3]) or girls (lowest tertile = 1.9 [1.7, 2.1] snacks/day, highest tertile = 2.2 [1.9, 2.4]). The mean ED of snacks decreased as DGI-CA scores increased in both boys (lowest tertile = 8.42, 95% CI [7.1, 10] kJ/g, highest tertile = 6.32 [5.4, 7.4] kJ/g) and girls (lowest tertile = 8.99 [7.8, 10.3] kJ/g, highest tertile = 5.92 [5.1, 6.9] kJ/g). As DGI-CA scores increased, the proportion of both boys and girls consuming discretionary foods at snacks (such as soft drinks) decreased, while foods from the five food groups (such as apples) increased (p-values < 0.05). In conclusion, snack ED, but not frequency, and the types of foods consumed by adolescents at snacks varied by a level of diet quality. Snack ED decreased with increasing diet quality and adolescents with higher diet quality had higher intakes of foods from the five food groups and lower intakes of discretionary foods at snacks. Encouraging the consumption of lower-ED foods from the five food groups at snacks presents an opportunity to enhance adolescent diet quality. Future studies should explore snack-specific strategies to improve overall diet quality of adolescents.

Sleep deprivation, which is a decrease in duration and quality of sleep, is a common problem in today’s life. Epidemiological and interventional investigations have suggested a link between sleep deprivation and overweight/obesity. Sleep deprivation affects homeostatic and non-homoeostatic regulation of appetite, with the food reward system playing a dominant role. Factors such as sex and weight status affect this regulation; men and individuals with excess weight seem to be more sensitive to reward-driven and hedonistic regulation of food intake. Sleep deprivation may also affect weight through affecting physical activity and energy expenditure. In addition, sleep deprivation influences food selection and eating behaviours, which are mainly managed by the food reward system. Sleep-deprived individuals mostly crave for palatable energy-dense foods and have low desire for fruit and vegetables. Consumption of meals may not change but energy intake from snacks increases. The individuals have more desire for snacks with high sugar and saturated fat content. The relationship between sleep and the diet is mutual, implying that diet and eating behaviours also affect sleep duration and quality. Consuming healthy diets containing fruit and vegetables and food sources of protein and unsaturated fats and low quantities of saturated fat and sugar may be used as a diet strategy to improve sleep. Since the effects of sleep deficiency differ between animals and humans, only evidence from human subject studies has been included, controversies are discussed and the need for future investigations is highlighted.

This study examined differences in food groups consumed at eating occasions by the level of adherence to dietary guidelines in Australian adults (≤19 years) and whether consumption differed with respect to age, sex and education levels. Secondary analysis of the 2011–2012 National Nutrition and Physical Activity Survey (n 9054) was performed, using one 24-h dietary recall with self-reported eating occasions. Dietary Guideline Index scores were used to assess adherence to the 2013 Australian Dietary Guidelines. Mean differences (95 % CI) in servings of the five food groups and discretionary foods at eating occasions were estimated for adults with higher and lower diet quality, stratified by sex, age group and education. Using survey-based t-tests, differences of at least half a serving with P values < 0·05 were considered meaningful. Compared with adults with lower diet quality, women and men aged 19–50 years with higher diet quality consumed more serves of vegetables at dinner (mean difference (95 % CI), women; 1·0; 95 % CI (0·7, 1·2); men: 0·9; 95 % CI (0·6, 1·3)) and fewer serves of discretionary foods at snacks (women: −0·7; 95 % CI (−0·9, −0·5); men: −1·0; 95 % CI (−1·4, −0·7). Other food groups, such as grains, dairy products and alternatives, meats and alternatives, were not significantly different between adults with lower and higher diet quality, across any eating occasions and age groups. Discretionary food intake at lunch, dinner and snacks was consistently greater among adults with lower diet quality, regardless of education level. Our findings identify dinner and snacks as opportunities to increase vegetable intake and reduce discretionary food intake, respectively.

Epidemiological evidence on the association between eating frequency and overall diet quality does not represent a consistent picture. This cross-sectional study examined the associations of meal frequency and snack frequency with diet quality, using different definitions of meals and snacks. Based on 4-d weighed dietary record data obtained from 639 Japanese adults aged 20–81 years, all eating occasions were divided into meals or snacks based on either the participant-identified or time-of-day definitions. Diet quality was assessed by the Healthy Eating Index-2015 (HEI-2015) and Nutrient-Rich Food Index 9.3 (NRF9.3). One additional meal per d increased the HEI-2015 total score by 3·6 and 1·3 points based on the participant-identified and time-of-day definitions, respectively. A higher meal frequency was also associated with higher values of some of the HEI-2015 component scores (total vegetables, greens and beans, and total protein foods), irrespective of how meals were defined. Additionally, one additional participant-identified snack per d increased the HEI-2015 total score by 0·7 points. The frequency of participant-identified snacks also showed positive associations with some of the HEI-2015 component scores (total fruits, whole fruits, total vegetables, greens and beans, dairy products, and Na). However, the frequency of time-of-day defined snacks was not associated with the total scores of HEI-2015, although there were some associations for its components. Similar findings were obtained when the NRF9.3 was used. In conclusion, higher meal frequency was consistently associated with higher diet quality, while associations between snack frequency and diet quality varied depending on the definition of snacks.

Food and energy intake can be effectively lowered by changing food properties, but little is known whether modifying food shape is sufficient to influence intake. This study investigated the influence of cracker shape and cheese viscosity on ad libitum intake of cracker–cheese combinations. Forty-four participants (thirteen males, 23 (sd 3) years, BMI 21 (sd 2) kg/m2) participated in four late afternoon snack sessions (2 × 2 randomised crossover design). Iso-energetic crackers were baked into flat squares and finger-shape cylindrical sticks and combined with a cheese dip varying in viscosity. Approximately eighty crackers and 500 g cheese dip were served in separate large bowls. Participants consumed crackers with cheese dip ad libitum while watching a movie of 30 min. Dipping behaviour and oral processing behaviour were measured simultaneously by hidden balances under the cheese bowls and video recordings. Cracker intake (28 (sem 1) crackers) of cracker–cheese combinations was not influenced by cracker shape. Cheese intake of cracker–cheese combinations was 15 % higher for flat-squared than finger-shape crackers (131 kJ, P = 0·016), as a larger amount of cheese was scooped with flat-squared crackers (2·9 (sem 0·2) v. 2·3 (sem 0·1) g cheese per dip, P < 0·001) and showed higher eating rate and energy intake rate (P < 0·001). Eating rate over snacking time decreased by reducing bite frequency (P < 0·001) while cheese dip size remained fairly constant (P = 0·12). Larger energy intake from condiments was facilitated by increased cracker surface, and this did not trigger earlier satiation. Changing food carrier surface may be a promising approach to moderate energy intake of often high energy dense condiments, sauces and toppings.

Adolescents’ snack choices could be altered by increasing the reinforcing value (RV) of healthy snacks compared with unhealthy snacks. This study assessed whether the RV of fruit increased by linking it to a reward and if this increased RV was comparable with the RV of unhealthy snacks alone. Moderation effects of sex, hunger, BMI z-scores and sensitivity to reward were also explored. The RV of snacks was assessed in a sample of 165 adolescents (15·1 (sd 1·5) years, 39·4 % boys and 17·4 % overweight) using a computerised food reinforcement task. Adolescents obtained points for snacks through mouse clicks (responses) following progressive ratio schedules of increasing response requirements. Participants were (computer) randomised to three experimental groups (1:1:1): fruit (n 53), fruit+reward (n 60) or unhealthy snacks (n 69). The RV was evaluated as total number of responses and breakpoint (schedule of terminating food reinforcement task). Multilevel regression analyses (total number of responses) and Cox’s proportional hazard regression models (breakpoint) were used. The total number of responses made were not different between fruit+reward and fruit (b −473; 95 % CI −1152, 205, P=0·17) or unhealthy snacks (b410; 95 % CI −222, 1043, P=0·20). The breakpoint was slightly higher for fruit than fruit+reward (HR 1·34; 95 % CI 1·00, 1·79, P=0·050), whereas no difference between unhealthy snacks and fruit+reward (HR 0·86; 95 % CI 0·62, 1·18, P=0·34) was observed. No indication of moderation was found. Offering rewards slightly increases the RV of fruit and may be a promising strategy to increase healthy food choices. Future studies should however, explore if other rewards, could reach larger effect sizes.

This cross-sectional study examined how energy density (ED) of meals and snacks are associated with overall diet quality and adiposity measures in 1617 British children aged 4–18 years from the 1997 National Diet and Nutrition Survey. On the basis of data from 7-d weighed dietary record, all eating occasions were divided into meals or snacks on the basis of time (meals: 06.00–09.00, 12.00–14.00 and 17.00–20.00 hours; snacks: all others) or contribution to energy intake (EI) (meals: ≥15 %; snacks: <15 %). ED of meals and snacks was calculated on the basis of food only. Overall diet quality was assessed using the Mediterranean diet score (range 0–8). Irrespective of the definition of meals and snacks, ≥67 % of EI was derived from meals, whereas ED of meals was lower than ED of snacks (mean: 8·50–8·75 v. 9·69–10·52 kJ/g). Both ED of meals and ED of snacks were inversely associated with total intakes of vegetables, fruits, dietary fibre and overall diet quality and positively associated with total intakes of fat. However, the associations were stronger for ED of meals. The change in the Mediterranean diet score with a 1-unit increase of ED (kJ/g) was −0·35 to −0·30 for ED of meals and −0·09 to −0·06 for ED of snacks (all P<0·0001). After adjustment for potential confounders, all measures of ED of meals and snacks did not show positive associations with adiposity measures. In conclusion, although both ED of meals and ED of snacks were associated with adverse profiles of overall diet quality (but not adiposity measures), stronger associations were observed for ED of meals.

This cross-sectional study examined how energy density (ED) in meals and snacks is associated with overall diet quality, BMI and waist circumference (WC). On the basis of the data from 7-d weighed dietary record, all eating occasions were divided into meals or snacks based on time (meals: 06.00–10.00, 12.00–15.00 and 18.00–21.00 hours; snacks: others) or contribution to energy intake (EI) (meals: ≥15; snacks: <15%) in 1451 British adults aged 19–64 years. Irrespective of the definition of meals and snacks, both meal ED and snack ED (kJ/g; calculated on the basis of solid food only) were inversely associated with overall diet quality assessed by the healthy diet indicator (regression coefficient (β)=−0·29 to −0·21 and −0·07 to −0·04, respectively) and Mediterranean diet score (β=−0·43 to −0·30 and −0·13 to −0·06, respectively) in both sexes (P≤0·002), although the associations were stronger for meal ED. After adjustment for potential confounders, in both men and women, meal ED based on EI contribution showed positive associations with BMI (β=0·34; 95% CI 0·06, 0·62 and β=0·31; 95% CI 0·01, 0·61, respectively) and WC (β=0·96; 95% CI 0·27, 1·66 and β=0·67; 95% CI 0·04, 1·30, respectively). In addition, meal ED based on time was positively associated with WC in men (β=0·59; 95% CI 0·07, 1·10) and snack ED based on time was positively associated with BMI in women (β=0·15; 95% CI 0·04, 0·27). In analyses in which only acceptable EI reporters were included, similar results were obtained. In conclusion, the findings suggest stronger associations of meal ED with overall diet quality, BMI and WC compared with snack ED.