School lunch nutritional adequacy: what is served, consumed and wasted.

OBJECTIVE: To determine nutritional adequacy of school lunch and to assess the impact of food waste on nutrient intake of primary schoolchildren. DESIGN: The weighing method was used for evaluating initial servings and plate waste for lunch. Energy and nutritional contents of meals served, consumed and wasted were estimated using the software Food Processor Plus. The mean nutritional value of food served and consumed was compared with dietary guidelines. SETTING: Portuguese public primary schools in the city of Porto. PARTICIPANTS: All 525 fourth-grade children, aged from 9 to 10 years old, attending to twenty-one public primary schools. RESULTS: Overall, school lunches served did not meet the dietary guidelines for energy and nutrients, as only 12·5 % of the evaluated meals were adequate for energy, 33·5 % for proteins, 11·9 % for carbohydrates and 57·1 % for lipids. The majority of meals served were below the age-specific lower limit, namely for energy (83·7 %) and carbohydrates (86·8 %). The only exception, also unbalanced, was observed for proteins, as 42·4 % of lunches served exceeded the recommended upper limit. Furthermore, lunches served and consumed by children did not meet the dietary guidelines for fibre and for the micronutrients evaluated. Children wasted 26 % of the energy content provided in lunches, corresponding to 91·5 kcal, 25 % of proteins and 29 % of carbohydrates supplied. CONCLUSIONS: The lunches served and consumed by children at school canteens failed to meet nutritional standards. These results are not only a consequence of inadequate food portions served but also a result of the high plate waste values observed.

Strategies to reduce plate waste in primary schools - experimental evaluation.

OBJECTIVE: To determine and compare the effect of two interventions in reducing the plate waste of school lunches. DESIGN: A between-group analysis was conducted among children from three primary schools: (i) a group receiving intervention A, designed for children and focusing on nutrition education and food waste; (ii) a group receiving intervention B, intended for teachers and focusing on the causes and consequences of food waste; and (iii) a control group with no intervention. For each child, physical weighing of individual meals and leftovers was performed on three non-consecutive weeks at baseline (T0), 1 week (T1, short term) and 3 months (T2, medium term) following the intervention. Plate waste was recorded for a total of 1742 lunches during 14 d over eight different menus. SETTING: Portuguese public primary schools in the city of Porto. SUBJECTS: All fourth-grade children (n 212) attending the three preselected schools. RESULTS: After intervention A focusing on nutrition education designed for children, a decrease in soup waste was observed compared with the control group. The effect was greater at T1 (-11·9 (se 2·8) %; P<0·001) than at T2 (-5·8 (se 4·4) %; P=0·103). The plate waste of identical main dishes decreased strongly at T1 (-33·9 (se 4·8) %; P<0·001). However, this effect was not found at T2 (-13·7 (se 3·2) %; P<0·001). After intervention B involving teachers, plate waste decreased at T2 (-5·5 (se 1·9) % for soup; -5·4 (se 2·4) % for identical main dishes). CONCLUSIONS: Nutrition education designed for children was more effective in the short than the medium term. Thus, this kind of intervention was not effective in reducing food waste in the medium term. In contrast, an intervention focusing on teachers revealed better results in the medium term than in the short term.

Cross-Classification Analysis of Food Products Based on Nutritional Quality and Degree of Processing.

This study aims to compare the classification of foods available in the Portuguese market using Nutri-Score and NOVA classifications and to analyse their ability to discriminate the fat, saturated fat, sugar, and salt content of foods. A sample of 2682 food products was collected. The nutritional quality of foods was established using the Nutri-Score, classifying them into five categories (from A to E). The NOVA classification was used to classify foods according to the degree of food processing into unprocessed/minimally processed foods, processed culinary ingredients, processed foods, and ultra-processed foods (UPF). The nutritional content of food products was classified using a Multiple Traffic Light label system. It was observed that 73.7% of UPF were classified as Nutri-Score C, D, and E, 10.1% as Nutri-Score A, and 16.2% as Nutri-Score B. Nutri-Score was positively correlated with NOVA classification (ρ = 0.140, p < 0.001) and with the Multiple Traffic Lights system (ρTotal Fat = 0.572, ρSaturated Fat = 0.668, ρSugar = 0.215, ρSalt = 0.321, p < 0.001). NOVA classification negatively correlated with the Multiple Traffic Lights system for total fat (ρ = -0.064, p < 0.001). Our findings indicate the presence of many UPFs in all Nutri-Score categories. Since food processing and nutritional quality are complementary, both should be considered in labelling.

The SHED Index: A Validation Study to Assess Sustainable HEalthy Diets in Portugal.

This study aims to adapt and validate the Sustainable HEalthy Diet (SHED) Index for the Portuguese adult population, which was developed to assess sustainable and healthy eating patterns. Data were collected using a web-based questionnaire administered through interviews with 347 individuals aged between 18 and 65 years old. The SHED Index evaluates 30 items, allowing for the assessment and scoring of sustainable and healthy eating patterns. The higher the SHED Index score, the more sustainable and healthier the diet. A semi-quantitative food frequency questionnaire was used to assess the participants' dietary intake. The criterion validity was examined by testing the relationship between the SHED Index score and adherence to the Mediterranean Diet. Reproducibility was assessed by determining agreement and reliability with test-retest. Construct validity was confirmed based on established criteria. A higher SHED Index score was associated with moderate to high adherence to the Mediterranean diet, while it was inversely related to the proportion of animal-sourced foods in the overall food intake (r = -0.281, p < 0.001). Good reliability and agreement were found for the SHED Index score. Our findings suggest that the SHED Index is a valid and reliable tool for assessing sustainable and healthy diets in the Portuguese adult population.

Factors influencing food waste during lunch of fourth-grade school children.

This study aims to explore the factors that influence plate waste at lunches served in primary schools. Data was collected for all fourth-grade children attending 21 primary schools from the city of Porto (Portugal) (n = 463). Plate waste was evaluated by the weighing method and factors influencing plate waste were collected by observation of menu and canteen characteristics and through the application of a questionnaire to children aiming to evaluate factors related to preferences and dietary patterns. Logistic regression was performed to identify predictors of plate waste. It was observed that fish menus and composed dishes showed a higher tendency for increased plate waste. However, this effect was not observed when adjusted for other variables. Soups without pulses and blended soups were less likely to be discarded by children. The presence of the teacher during meals and the possibility for children to leave the canteen whenever they wish, protected both the main dish and the soup from being wasted. A higher number of children in the canteen was associated with increased soup waste. As expected, children more pleased with the sensory characteristics of the main dish and soup were less likely to waste food. Children who consumed high-saturated fat content mid-morning snacks were more likely to waste soup. The main factors associated with plate waste were related to the presence of teachers during the mealtime, school meal policies and the meals' sensory characteristics. Additionally, soup waste was determined by its composition, mid-morning snacks and the number of children in the canteen.

Determination of plate waste in primary school lunches by weighing and visual estimation methods: a validation study.

The aim of this study was to validate the visual estimation method for aggregated plate waste of main dish at Portuguese primary school canteens. For this purpose plate waste at school lunch was measured for 505 individual servings, using weighing individual servings and plate waste and visual estimation method by a 6-point scale, as developed by Comstock et al. (1981). A high variability of initial serving weights was found with serving sizes ranging from 88.9 to 283.3g and with a coefficient of variation ranging from 5.5% to 24.7%. Mean plate waste was 27.5% according to the weighing method. There was a significant bias in the conversion of the visual waste estimations to actual waste, being overestimated by an average of 8.0 g (ranging from -12.9 g to 41.4 g). According to Bland and Altman plot, the mean difference between methods was of 8.0 g and the amplitude interval was 102.6g. The study showed that the visual estimation method is not as accurate as the weighing method in assessing nonselective aggregated plate waste at primary school canteens. Our findings are thus very important on considering plate waste assessment, since the wide variation on initial servings introduces a relevant bias when considering standard portions or a random sample of initial servings. Although, greater convenience, time-saving and the possibility to monitor plate waste of large groups, make the visual estimation method an important method to assess plate waste at school canteens, these results highlighted the need of portions standardization and control of initial servings to allow for its use.